TOXICOLOGY AND APPLIED PHARMACOLOGY 19, 276-360 (1971) 

Study of Intra- and Interlaboratory Variability in the 

Results of Rabbit Eye and Skin Irritation Tests 

CARROL S. WEIL AND ROBERT A. SCALA 

Mellon Institute, Carnegie-Mellon University, 

Pittsburgh, Pennsylvania 15213, 

and 

Esso Research and Engineering Company, 

Medical Research Division, Linden, Nen, Jersqv 07036 

Received October 12, 1970 

Study of Intra- and Interlaboratory Variability in the Results of Rabbit 

Eye and Skin Irritation Tests. WEIL, C. S., and SCALA, R. A. (1971). Toxicol. 

Appl. Pharmacol. 19, 276-360. Twenty-five laboratories supplied data for a 

joint study of the variability of test results. Each laboratory was to test skin 

and eye irritation by a reference and by a nonreference method for each of 

12 materials. 

The reliability and reproducibility of experimental findings are sub.ject to the influence of 

the particular procedure employed in conducting the test as well as to variability among 

the scientists who interpret the results. Many laboratories of toxicology have attained a 

degree of internal consistency through the use of their own unique experimental designs. 

There is little information on the consistency of results among laboratories, each of 

which has used its own design. Most of the available data refer to the acute oral test. A 

fundamental question is whether these individualized procedures are more or less 

reliable in the measurement of effect than an arbitrary or reference procedure. The 

promulgation of such fixed methods by government regulatory agencies implies that 

reliability and reproducibility are attained only by standardization. This assumption 

was tested for the acute oral test in a cooperative study reported by Weil and Wright 

(1967). They found no need for such standard techniques and concluded that competent 

laboratories will generally be in good agreement even though methods may vary. 

Since Draize’s initial publication (Draize et al., 1944) of methods for studying skin 

and mucous membrane irritants, there have been many reports of methods for eye and 

skin testing; interpretations of the results of such tests; interspecies comparisons; and, 

for eye irritants, a series of color plates to aid in grading responses. A selected bibliography of such papers accompanies this study. Among the criteria for inclusion were 

reports of methodology in man or experimental animals and the results of studies on 

cosmetic products and topical drugs. Specifically excluded were studies on sensitization, 

clinical case reports, and screening studies of industrial chemicals. 

No published report has been found which contains data on eye and skin irritation 

from reference materials using reference and nonreference procedures. A collaborative 

program was set up to examine these variables in a sizable number of established laboratories; the present report describes the results of these inter- and intralaboratory comparisons. 

276 
INTERLABORATORY EYE AND SKIN COMPARISONS 277 

METHODS 

After a preliminary survey of potentially interested investigators, it was agreed to test 

eye and skin irritation by a reference and a nonreference method, the latter being the 

method commonly used in each individual laboratory. Invitations were sent to over 50 

laboratories in the United States, Canada, and England to join in the program. This 

original list included governmental, consulting, food, chemical, cosmetics, and 

toiletries laboratories known to conduct eye and skin irritation testing on experimental 

animals. Thirty-one laboratories accepted and 25 provided data in at least a portion of 

the program. The participating laboratories are listed in Table 1 along with a tabulation 

by laboratory type showing to which phase of the collaborative program each contributed data. The listing in Table 1 is alphabetical. However, each laboratory was ranTABLE 1 

LABORATORIES THAT PARTICIPATED IN THE COLLABORATIVE 

EYE AND SKIN IRRITATION TEST PROGRAM 

Type” Laboratory 

C 

I 

I 

T 

T 

T 

G 

T 

I 

I 

G 

C 

I 

C 

C 

C 

C 

C 

C 

T 

I 

G 

T 

T 

C 

AME, Inc. 

American Cyanamid Company 

Atlas Chemical Industries, Inc. 

Applied Biological Sciences Laboratories, Inc. 

Avon Products, Inc. 

Bristol-Myers Products 

Bureau of Occupational Safety and Health, DHEW, PHS 

Colgate-Palmolive Company 

The Dow Chemical Company 

Eastman Kodak Company 

Food and Drug Directorate, DNHW, Canada 

Food and Drug Research Laboratories, Inc. 

General Foods Corporation 

Gulf South Research Institute 

Hazleton Laboratories, Inc. 

Hill Top Research, Inc. 

Huntingdon Research Centre, England 

Industrial Bio-Test Laboratories, Inc. 

International Research and Development Corporation 

Lever Brothers Company 

Mellon Institute; Carnegie-Mellon University 

Pesticides Regulation Division, USDA, ARC 

The Procter & Gamble Company 

Revlon Research Center, Inc. 

WARF Institute, Inc. 

Eye test 

NonReference reference 

Skin test 

NonReference reference 

n Symbol Type of laboratory method method method method 

C Consultant 9 6 8 6 

I Food or industrial chemical 6 5 6 6 

T Toilet goods and cosmetics I 5 5 5 

G Governmental 2 1 3 2 

24 li 22 19 
278 WEIL AND SCALA 

domly assigned a code number which has been used in the tabulation and discussion of 

the data. 

An ad hoc Steering Committee’ prepared the reference methods for eye and skin testing. The laboratories were urged to follow precisely the procedures. Practical considerations precluded any attempt to control the source of the experimental animals. 

A. Reference Methodfor Eye Irritation Test 

Animals. Six male albino rabbits in good health, weighing at least 2.0 kg each, were 

used for each material. The eyes were free of defects and irritation, and 24 hr prior to 

application of test material the eyes were stained with an aqueous 5 7; solution of sodium 

fluorescein. The stain was allowed to contact the eyes for 20 set and was flushed 

thoroughly with distilled water at room temperature, The eyes were then examined for 

possible cornea1 lesions not otherwise visible. Three left and 3 right eyes were used for 

each sample. The animals were housed singly and free of any extraneous material which 

might cause irritation. 

Application. The lower lid was pulled away from the eye to form a cup into which 0.1 

ml of material was instilled. The lid was held open for a few seconds, then raised to close 

with the upper lid. The 2 lids were held gently together for a few seconds before the 

animal was released. The eyes were not washed following instillation. 

Scoring and eraluation. The eyes were examined and the degree of irritation recorded 

at 1, 24, and 72 hr and 7 days after application of the sample. Observations on any 

animal were discontinued after 24 or 72 hr if the eyes were free of irritation. Fluorescein 

staining was done at 24 and 72 hr and 7 days on the eyes of animals not previously negative. The grading of eye irritation was according to the scale of Draize et al. (1944). 

Injuries such as pannus, keratoconus, and sloughing of cornea1 epithelium were not 

included in the Draize system and were recorded separately. The scale for scoring irritation and a data sheet for one sample are included in the appendix. 

B. Reference Method,for Skin Irritation Test 

Animals. Eight male albino rabbits in good health and weighing at least 2.0 kg each 

were used for each group of 4 materials. Immediately prior to applying the materials 

the hair was removed from the backs of the animals with electric clippers in such a way 

as to avoid abrasions. The clipped area was wide enough to accommodate 4 gauze pads 

without overlapping. The animals were placed in restraint at the time the materials were 

applied and they remained immobilized during the 24-hr exposure period. 

Application. Four gauze patches, each 1” x 1” cut from nonsterile, 12-ply material, 

were fixed to the application sites on each animal by means of l/2-inch adhesive tape 

applied in the shape of an X. The test material was applied by injecting 0.5 ml from a 

syringe and needle into the estimated center of the gauze pad. Uniform contact of sample 

with skin was ensured by pressing the pad firmly against the skin with the thumb. Four 

materials were applied to the intact skin of 8 rabbits according to the following scheme, 

which permits variation of actual sites: 

Rabbit numbers 1,2 3,4 56 7,8 

Compounds 12 21 34 43 

34 43 12 21 

’ The membership of the Steering Committee was Steven Carson, Kenneth J. Olson, Donaid L. 

Opdyke, Robert A. Scala, Fred H. Snyder, and Carrol S. Weil. 
INTERLABORATORY EYE AND SKIN COMPARISONS 279 

Thus compound 1 was in position 1 for rabbits 1 and 2, in position 2 for rabbits 3 and 4, 

etc. The trunk of each rabbit was wrapped with an impervious Saran film supplied by 

the Dow Chemical Company and held in place longitudinally with tape. The covering 

was loose enough to permit insertion of 4 fingers of the hand horizontally between the 

cuff and the animal. The ends of the covering were left open. 

Scot-&q and evaluation. Twenty-four hr after application the patches were removed, 

and 30 min later the skin sites examined. The examination was repeated 48 hr later (72 hr 

after application). Scoring of the reactions was based on the amount of erythema, 

edema, and necrosis found. Necrosis was defined in this instance as “chemical 

denaturation of tissue sufficiently severe to result in fibrotic replacement (scar tissue). 

Superficial eschar which heals without scar is not classified as necrosis.” The skin reaction scores of each animal in each category at 24 and 72 hr after application were added. 

The total score for all 8 rabbits was divided by 16 to yield a Primary Irritation (PI) score 

for a given material. The scoring scale and a sample score sheet are in the appendix. 

C. Nonreference Methods 

Each laboratory was also asked to test the materials according to the procedures they 

used routinely for eye and skin irritation. In reporting those data, the laboratories were 

requested to provide information on species and strain of animal, sex, age and/or weight 

range, method of application, scale of irritation response, score assigned to any given 

response, and any other pertinent data. Samples tested by these nonreference methods 

were to be ranked by the laboratory on the basis of their irritation with the most 

irritating given a rank of 1, the next most irritating a rank of 2, etc. A similar ranking 

was to be made by each laboratory for eye and skin data using the reference methods. 

D. Statistical Procedures 

Generally, nonparametric procedures were used for inter- or intralaboratory (or 

between-sample) comparisons. Median scores for eye injury or primary irritation scores 

for skin irritation were ranked, usually assigning a rank of 1 for the most severe, 2 for 

the next most severe, . . . and N for the least severe reaction. These ranks were then 

summed for each laboratory (or for each sample). The significance of the sums of ranks 

was compared to the limits calculated by the method presented by Thompson and 

Willke (1963). 

In the repeat tests in 2 laboratories, the results of the 2 technicians in each laboratory 

were compared by the signed rank sum test (Wilcoxon et al., 1963). The Spearman rank 

correlation coefficient was used to intercompare results of the reference and nonreference procedures (Snedecor and Cochran, 1967). 

E. Mater& 

Initially 12 materials, primarily constituents of cosmetics, were selected for inclusion 

in the study. As the collaborative testing progressed, it was clear that some materials 

were completely nonirritating. This lack of irritancy would reduce the power of the 

collaborative test to discriminate between methods or laboratories on the basis of irritation scores. Therefore, 4 of the original materials were dropped and 4 industrial chemicals of pretested irritancy were added to the program. Each test material was from a 
280 WEIL AND SCALA 

single lot, and aliquots were repacked and shipped under code from a single point to all 

participants. 

The materials used and the identifying code are listed in Table 2. Samples B, C, D, and 

H were later dropped as nonreactive and replaced by Samples M, N, 0, and P. The 

identification of the samples was not available to the participants. 

TABLE 2 

MATERIALS USED IN COLLABORATIVE 

EYE AND SKIN IRRITATION TESTS 

Code Material 

A 

B 

C 

D 

E 

F 

G 

H 

I 

J 

K 

L 

M 

N 

0 

P 

Ethanol, 95 “/‘, 

Propylene glycol 

Formaldehyde, 2 7: 

Glycerin 

Isopropyl myristate 

Triethanolaminelauryl sulfate, 46 7; aqueous 

Cream peroxide, 20 volume 

Aluminum chlorhydroxide, 50 % aqueous 

Triethanolamine 

Ethoxylated lauryl alcohol 

Decaethoxy oleyl ether 

Linoleic diethanolamide 

n-Butyl alcohol 

Methyl ethyl ketone 

Methyl isobutyl ketone 

Ethylene glycol monoethyl ether 

RESULTS 

A. Low-Differentiating Materials 

It was noted, when the results from the first group of laboratories had been received, 

that some materials had a consistently low order of eye and/or skin irritation reaction. 

This lack of irritation was not surprising, on reconsideration, as the initial 12 materials 

were chosen, as stated before, to be typical of those used by the cosmetic or toilet-goods 

industries. The data from all laboratories tended to agree on these, and their inclusion 

in the correlations resulted in significant correlations that often disappeared if their 

results were removed (Tables 56 and 57, for example). At first the results of B, C, D, and 

H were removed. Later E, I, and 0 for the eye as well as A and P for the skin tests were 

deleted. The latter 3 for the eye test or 2 for the skin test are the compounds still included 

in the 9 uer.sus 12 materials for the eye test and the 10 versus 12 materials for the skin test 

compared in Tables 56 and 57; the results will be discussed in Section E. 

The eye and skin reactions on the reference tests, found in each laboratory for these 

low-differentiating materials, are presented in Table 62. These primarily negative data 

were not included in the majority of the succeeding comparisons and discussions. 
TABLE 3 

EYE-MEDIANS AND SCORES OF INDIVIDUAL RABBITS TREATED WITH 95 “,I ETHANOL 

24 Hr-rabbit number 

- 

72 Hr-rabbit number 7 Days-rabbit 

Laboratory 

No. 1 2 3 45 6 12 3 4 5 6 I 

--__ - --___ - __--- 

63 25 65 8 51 25 65 6 

47 49 59 4 66 19 9 19 

55 57 38 4 10 26 28 24 

40 50 50 14 48 16 21 38 

17 29 39 15 59 20 13 8 

37 35 37 36 19 11 41 15 

25 32 20 18 33 23 4 24 

55 45 30 9 14 14 40 18 

35 37 15 7 37 17 4 4 

37 37 37 0 6 30 4 0 

19 33 35 2 16 9 9 4 

23 15 23 11 19 8 17 2 

28 5 0 35.5 10 31 0 0 

28 15 22 12 2 39 23 9 

13 17 21 39 43 41 0 63 

19 19 36 2 9 22 15 38 

9 16 15 0 9 9 9 5 

23 13 2 8 9 7 13 6 

100 4 40 7 2 2 26 7 

17 21 8 22 2 4 4 6 

9 43 43 6 6 16 0 11 

64 2 0 0 2 2 0 

10 0 6 2 0 0 2 0 

029 0 0 4 0 0 49 

29 38 59 41 

1 23 49 41 

4 32 30 62 

14 40 58 38 

12 39 44 39 

25 39 35 35 

9 37 35 30 

31 25 26 30 

22 13 35 15 

13 0 12 2 

23 15 18 28 

16 19 21 25 

18 22 22 19 

I1 19 11 27 

24 15 17 21 

7 2 11 15 

10 33 18 22 

27 20 15 18 

2 26 4 4 

5 27 8 8 

21 9 9 II 

30 4 6 6 

19 12 4 4 

8 5 4 0 

61 2 

57 2 

24 2 

38 0 

59 6 

9 4 

13 15 

7 0 

9 0 

50 0 

31 4 

17 2 

0 0 

2 0 

59 53 

110 0 

7 0 

2 4 

14 0 

2 2 

7 0 

0 0 

0 0 

0 0 

2 3 4 

-.~~~ ~__ ~- 

10 I1 30 

57 0 0 

0 4 5 

12 0 0 

21 6 6 

2 2 9 

5 10 0 

0 0 0 

44 0 0 

4 2 2 

4 4 0 

2 2 4 

0 2.5 0 

0 4 12 

57 59 0 

0 35 16 

0 5 5 

0 0 0 

0 0 49 

0 2 4 

0 0 5 

0 0 0 

0 0 0 

0 0 0 

- __-~- 

Median of labor
TABLE 4 

EYE-MEDIANS AND SCORES OF INDIVIDUAL RABBITS TREATED WITH 46 :,I AQUEOUS TRIETHANOLA

(MATERIAL F) 

24 Hr-rabbit number 72 Hr-rabbit number 7 Days-rabbit 

Laboratory ~ ~~ -~ -~ - ~ .~--- 

.___ ~_____ ~ 

No. 12 3 4 5 6 12 3 4 5 61 2 3 4 

-~ __.~~~ 

21 76 76 80 78 76 74 53 61 21 21 

4 70 58 46 54 94 94 62 79 39 46 

29 58 65 65 70 63 61 52 57 66 62 

14 60 60 58 58 60 60 56 48 58 56 

10 42 40 51 51 48 57 35 16 31 26 

2 25 54 52 40 48 50 9 50 57 45 

7 42 42 46 50 48 50 32 36 51 55 

1 57 45 35 55 47 45 47 41 55 43 

12 30 41 46 43 59 43 20 66 39 57 

22 41 39 30 32 37 34 37 35 35 35 

23 33 24 33 29 35 35 12 12 22 24 

9 26 32 34 30 34 30 22 32 41 20 

31 26 33 28 35 33 28 46 43 28 33 

25 23 29 35 27 26 31 11 6 24 13 

11 28 25 26 11 33 37 30 11 11 15 

27 24 24 14 19 24 24 24 24 9 14 

5 19 22 27 31 6 26 2 6 6 29 

18 18 21 20 16 17 17 25 23 17 4 

16 8 18 14 14 18 18 0 20 16 6 

19 15 15 19 19 17 15 15 13 19 17 

13 37 12 12 39 18 2 28 2 2 24 

24 11 8 31 37 19 12 33 35 31 35 

30 17 15 I5 12 19 15 22 33 37 20 

8 9 9 8 18 18 11 2 2 20 45 

28 66 5 0 0 14 

101 54 2 73 27 9 

54 51 59 28 45 28 

34 56 56 19 36 56 

24 28 33 4 9 4 

18 47 0 16 4 36 

22 51 5 34 36 55 

47 45 27 2 55 39 

59 59 46 82 35 18 

35 30 22 22 28 33 

53 24 0 0 5 7 

22 27 0 59 35 0 

30 30 46 18 11 28 

15 21 0 2 0 2 

37 41 31 2 7 7 

19 14 24 15 4 0 

2 22 0 2 4 31 

14 15 15 42 2 0 

61 110 0 16 4 2 

10 15 8 8 10 15 

48 452 6 0 2 

35 23 55 27 19 28 

22 30 13 39 20 4 

10 30 0 0 16 65 

Median of labora
TABLE 5 

EYE-MEDIANS AND SCORES OF INDIVIDUAL RABBITS TREATED WITH 20-VOLUME CREAM 

24 Hr-rabbit number 72 Hr--rabbit number 7 Days-rabbit 

3 4 5 61234561234 No. 

- 

29 90 63 88 90 79 

8 84 86 55 86 82 

1 82 86 62 86 55 

25 68 79 78 86 90 

16 17 79 81 8 85 

7 70 70 70 72 40 

12 66 64 84 11 90 

9 55 61 57 59 59 

21 52 56 56 56 54 

18 54 69 61.5 54 34 

10 59 59 39 43 39 

24 41 63 59 35 35 

19 48 50 48 70 33 

11 37 45 41 51 71 

14 56 60 36 56 26 

23 11 22 0 53 61 

13 57 48 6 0 46 

22 21 37 4 55 17 

31 51 13 23 53 31 

27 21 31 31 66 2 

5 26 29 29 26 17 

4 0 6 23 23 23 

30 30 11 11 11 2 

2 0 11 4 23 6 

_-- .-~ ~-__-~ 

37 90 38 86 86 80 14 65 24 78 82 

82 78 84 47 84 60 86 78 69 37 82 

82 78 71 62 84 55 82 2 2 72 72 

92 84 4 29 64 68 68 22 2 0 44 

110 6 47 49 4 65 45 4 12 43 0 

72 64 84 82 92 38 92 82 84 87 97 

22 82 14 80 0 84 2 80 7 78 0 

12 53 59 53 53 55 12 5 9 7 5 

22 42 68 53 70 72 6 49 49 49 49 

17 6.5 12.5 15 4.5 2.5 0 24 0 33 8 

59 47 37 18 32 31 33 9 31 7 24 

57 37 55 55 51 35 53 53 41 51 53 

48 48 48 46 50 26 46 42 42 42 42 

47 73 71 71 75 75 77 65 67 67 32 

26 54 76 34 54 7 46 54 78 12 54 

51 0 0 0 45 55 47 2 6 0 45 

26 44 22 0 0 42 55 0 4 0 

7919 9 2 20 0 77 12 5 2 20 

26 28 4 18 23 23 19 23 0 6 23 

11 29 64 64 64 0 4 10 65 60 60 

26 11 37 25 4 11 24 2 21 26 

25 0 2 21 14 19 16 0 0 17 1

9 12 19 7 4 4 9 17 63 7 

80504090000 

Median of lab
TABLE 6 

EYE-MEDIANS AND SCORES OF INDIVIDUAL RABBITS TREATED WITH 

ETHOXYLATED LAURYL ALCOHOL (MATERIAL J) 

Laboratory __ 

No. 1 

21 59 

14 60 

4 24 

29 41 

12 41 

2 55 

23 38 

1 32 

10 55 

9 30 

22 28 

31 29 

11 31 

5 20 

8 47 

19 43 

24 8 

25 10 

16 21 

30 16 

7 11 

18 2 

27 26 

13 30 

24 Hr-rabbit number 72 Hr-rabbit number 

- -__ ~ _. 

2 3 4 5 6 12 3 4 5 61 

7 Days-rabbit 

-~ ____ 

2 3 4 

49 81 83 79 79 30 14 31 36 35 24 5 2 4 5 

58 56 60 58 58 58 36 29 60 58 58 24 4 2 58 

53 57 57 9 51 21 57 77 7 21 5 7 83 85 

36 28 43 71 67 5: 34 32 43 88 108 35 6 9 47 

39 59 41 43 41 33 37 59 59 59 33 22 7 26 55 

4 28 28 52 57 42 0 37 15 100 79 10 0 9 0 

39 39 41 35 35 57 20 43 11 14 37 46 2 41 5 

35 23 48 40 35 23 24 19 29 17 28 2 0 0 0 

26 30 33 35 41 37 24 32 48 20 57 39 7 20 38 

0 34 32 43 37 7 0 26 19 61 43 0 0 21 4 

28 6 33 37 35 33 53 0 35 62 31 22 37 0 33 

26 28 31 33 19 53 74 38 73 33 5 38 38 26 28 

24 28 2 37 28 29 28 41 65 51 34 7 53 66 81 

25 25 27 27 31 18 37 20 29 22 33 9 32 20 36 

45 15 35 2 4 45 11 10 25 11 37 6 4 0 21 

11 43 33 14 9 28 9 43 21 9 5 10 9 14 9 

19 33 37 17 28 35 43 49 61 46 34 33 35 45 86 

21 23 36 15 21 39 43 45 6 4 2 39 37 61 0 

19 23 19 19 17 13 15 19 7 4 23 4 4 0 0 

16 11 13 13 8 32 31 37 41 26 35 54 69 67 49 

11 26 16 14 11 9 11 9 9 14 11 7 4 2 9 

11 11 11 7 13 5 18 18 9 0 23 0 25 25 0 

19 2 17 0 0 0 0 0 0 0 0 0 0 0 0 

12 0 2 4 10 37 37 0 59 63 63 2 0 0 53 

Median of labora
TABLE 7 

EYE-MEDIANS AND SCORES OF INDIVIDUAL RABBITS TREATED WITH DECAETHCIXY OLEYL 

24-Hr-rabbit number 

Laboratory -___ 

72-Hr-rabbit number 

NO. 12 3 4 5 6 12 3 4 5 6 1 

4 

29 

12 

19 

14 

31 

5 

16 

22 

9 

24 

7 

1 

10 

30 

2 

13 

21 

23 

11 

25 

18 

8 

27 

63 99 59 81 79 79 41 0 30 99 37 0 15 

41 43 41 14 37 36 63 60 30 8 14 90 49 

19 14 63 39 29 45 21 8 10 48 19 70 16 

26 43 55 19 17 38 13 24 36 17 8 15 0 

28 18 30 62 26 50 18 11 21 60 14 36 0 

52 52 8 13 28 28 42 37 12 4 37 52 18 

24 18 22 22 26 20 43 39 24 43 41 43 40 

30 23 21 21 18 19 19 3.5 26 35 20 70 2 

10 10 35 32 35 10 13 2 6 28 60 4 2 

21 28 17 10 37 19 17 36 4 8 33 21 0 

21 15 13 6 23 17 45 45 43 12 41 41 

30 13 13 16 18 11 30 11 13 1: 16 11 16 

13 10 13 15 37 15 11 8 11 6 30 13 4 

29 42 8 13 13 11 17 22 9 5 

22 13 13 13 17 10 13 17 2: 16 3: 1: 6 

8 12 15 13 49 4 63 26 17 11 29 9 14 

12 14 0 6 12 12 8 12 0 6 2 0 0 

12 12 12 10 12 12 4 6 8 4 6 14 9 

8 41 22 10 14 10 6 26 6 12 4 10 2 

32 6 39 6 10 6 74 6 55 4 10 4 68 

6 6 39 8 4 13 0 4 33 17 6 85 2 

45 5 8 6 6 12 13 13 28 22 13 10 6 

2 6 11 2 6 2 9 56 4 35 8 14 25 

4 4 4 4 4 4 5 4 4 4 4 4 0 

7 Days-rabbit 

105 34 30 

47 2 0 

6 8 10

24 22 IO 

4 4 36 

40 4 

55 28 34 

70 4 63 

0 0 53 

43 2 

41 61 

9 9 1

0 0 

2 2 

35 43 2

II 13 1

2 0 

0 0 

7 4 

4 35 

2 31 

6 29 

100 0 

0 2 

-- ~~~. 

Median of labor
286 WEIL AND SCALA 

W 

m 

d 
TABLE 9 

EC EYE-MEDIANS AND SCORESOF INDIVIDUAL RABBITSTREATED WITH IPBCJTYLALCOHOL

24-Hr-rabbit number 72 Hr-rabbit number 7 Days-rabbit 

Laboratory ~ ~~___ ~ ____- 

._~___. ~~ 

No. 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 

4 37 77 77 75 83 83 38 38 53 31 31 7 28 37 11 26 

14 50 60 60 58 52 58 38 42 48 56 58 58 24 19 19 54 

31 57 47 9 72 55 55 63 14 4 72 35 30 53 0 0 42 

2 80 92 4 45 43 57 15 36 4 2 90 82 20 0 0 0 

10 55 43 6 45 57 59 53 44 4 14 44 47 20 14 - 5 

12 46 46 46 46 39 34 44 66 44 66 35 42 6 8 8 42 

11 35 32 35 35 37 35 31 28 39 4 59 11 2 24 2 0 

25 37 33 35 33 35 33 8 33 29 33 28 31 2 26 2 2 

22 37 32 39 32 0 35 35 28 57 30 0 35 2 0 5 6 

9 32 33 37 35 33 30 15 20 35 16 33 9 5 35 45 0 

29 34 36 32 37 32 30 26 28 26 33 31 24 17 17 17 9.

1 45 28 23 28 33 33 60 23 16 14 21 19 24 2 0 0 

23 39 29 31 27 26 31 11 5 7 0 0 0 2 0 0 0 

27 24 2 24 29 2 28 7 2 29 22 2 4 0 0 0 0 

5 25 22 17 22 22 22 20 17 13 16 15 6 7 2 2 2 

24 23 21 21 21 19 6 33 31 37 33 33 0 2 2 0 2 

18 26 19 16 17 18 16 6 6 8 23.5 0 1 0 0 0 26 

13 6 16 16 16 10 16 2 10 12 12 52 10 4 2 2 4 

16 19 8 16 8 14 22 43 2 10 6 26 17 5 0 0 0 

19 17 6 45 29 10 0 0 0 4 6 0 0 0 0 2 2 

8 15 8 6 10 15 13 26 2 0 6 6 4 0 0 0 0 

30 11 9 12 2 2 42 2 0 0 7 0 0 0 0 0 0 

21 6 2 6 0 6 6 6 0 6 2 6 6 0 0 0 0 

7 4 2 0 2 4 2 2 0 0 2 2 2 0 0 0 2 

Median of labora
TABLE 10 

EYE-MEDIANS AND SCORES OF INDIVIDUAL RABBITS TREATED WITH METHYL ETHYL KE

24 Hr-rabbit number 72 Hr-rabbit number 7 Days-rabbit 

Laboratory 

No. 12 3 4 5 6 12 3 4 5 6 12 3 4 

14 21 50 48 60 60 60 9 36 36 58 62 21 0 19 19 36 

4 37 41 38 63 63 63 31 11 18 21 20 36 12 10 7 11 

10 46 53 53 16 35 2 14 44 16 9 16 0 0 7 - 7 

12 39 37 46 39 39 39 35 39 57 23 44 44 8 13 13 6 

11 35 33 33 30 23 34 21 26 19 30 4 13 2 21 2 2 

29 38 32 36 23 34 32 30 34 34 23 32 34 4 16 14 2 

2 48 9 63 8 61 16 7 7 37 0 7 9 4 0 5 0 

19 29 35 49 27 20 47 19 2 21 11 2 12 7 0 2 0 

31 57 25 9 27 47 35 18 25 4 4 9 9 0 0 0 0 

22 35 8 35 0 25 35 29 2 35 0 25 33 2 0 0 0 

5 27 27 22 22 20 22 22 13 11 6 13 22 9 7 2 0 

9 29 21 22 18 18 34 20 7 16 9 11 16 14 14 10 0 

24 17 15 21 21 17 17 31 13 19 35 11 4 2 0 2 0 

13 6 14 16 16 16 16 10 10 12 12 10 2 2 2 

30 15 13 15 15 15 15 1; 31 19 33 13 8 2 0 2 

4 

0 

1 8 18 11 11 11 6 2 2 0 7 2 2 0 0 0 0 

23 9 11 11 29 34 10 0 0 0 12 7 0 0 0 0 2 

25 6 13 8 35 4 13 2 35 2 11 2 4 2 0 0 2 

8 10 4 4 10 20 25 0 0 0 4 15 4 0 0 0 0 

16 8 8 23 8 10 10 2 0 21 4 6 2 0 0 0 0 

21 15 6 10 6 6 6 10 10 12 12 6 6 0 0 0 0 

18 4 12 8 2 6 4 0 0 6 0 2 10 2 0 0 

7 2 2 0 2 0 2 0 2 0 0 0 2 0 0 0 0 

27 2 31 4 2 2 2 0 26 2 0 2 0 0 33 0 0 

--. 

Median of labora
TABLE 11 

EYE-MEDIANS AND SCORES OF INDIVIDUAL RABBITS TREATED WITH ETHYLENE GLYCOL MONOET

24 Hr-rabbit number 72 Hr-rabbit number 

Laboratory 

No. 12 3 4 5 6 12 3 4 5 6 

- 

4 61 59 63 63 26 26 51 26 14 43 11 7 

I 18 47 40 45 64 45 4 35 29 21 41 16 

12 39 46 46 44 46 39 25 39 35 35 64 35 

14 34 38 26 52 46 46 26 14 19 36 46 34 

29 34 21.5 27 36 36 6 4 2 21 22 38 4 

22 10 30 20 30 35 32 10 28 13 30 35 30 

11 34 26 2 29 6 33 2 35 2 17 4 4 

23 27 37 18 27 22 30 17 6 5 0 7 15 

31 25 30 25 27 37 9 13 4 13 27 45 0 

5 22 17 25 17 29 31 13 6 I1 0 11 11 

2 18 9 65 0 32 28 0 0 9 0 5 0 

8 10 18 25 6 35 25 0 16 49 0 4 0 

10 35 11 14 9 26 28 9 2 2 2 7 9 

9 11 15 20 20 32 17 0 0 0 0 25 0 

13 32 16 12 17 12 16 56 12 6 6 6 32 

18 17 14 17 18 10 10 0 

11 1: 

4 19 8 4 

25 33 15 13 10 37 15 9 15 4 2 

16 14 12 12 16 10 4 12 12 12 12 6 2 

19 11 11 11 6 13 11 0 0 5 0 9 0 

24 11 10 8 10 15 17 0 33 8 2 24 32 

27 18 4 7 11 10 21 2 2 2 2 0 2 

21 4 4 8 0 0 6 0 0 0 0 0 0 

30 2 2 0 4 2 2 0 0 0 0 0 0 

7 2 0 0 2 2 0 2 0 0 2 2 0 

7 Days-rabbit 

1 2 3 4 

27 

0 

6 

0 

2 

2 

2 

0 

0 

4 

0 

0 

0 

0 

0 

0 

2 

0 

0 

0 

0 

0 

0 

0 

12 7 0 

12 0 0 

23 18 8 

12 0 9 

0 2 0 

0 0 13 

4 2 2 

2 0 2 

0 4 22 

4 6 0 

0 0 0 

5 54 0 

0 0 0 

0 0 0 

2 0 2 

6 0 6 

2 0 0 

0 0 0 

0 0 0 

4 0 0 

0 0 0 

0 0 0 

0 0 0 

0 0 0 

- 

Median of labor
TABLE 12 

MINIMUM-MAXIMUM SCOREFOREYESOF INDIVIDUALRABBITS-% HR REFERENC

Laboratory - -~ 

- 

No.” A F G J 

14 

29 

4 

12 

1 

10 

31 

22 

2 

9 

11 

23 

25 

21 

5 

19 

16 

24 

7 

13 

18 

8 

27 

30 

Any 

laboratory 

38-58 58-60 26-60 56-60 

25-65 58-70 37-90 28-71 

3C62 46-94 O-25 9-57 

17-44 30-59 1 l-90 39-59 

23-59 35-57 55-86 2348 

9-33 40-57 39-59 26-55 

25-55 26-35 13-53 19-33 

13-37 30-41 4-79 637 

4-100 25-54 &23 4-57 

20-37 26-34 12-61 O-43 

11-28 1 l-37 37-71 2-37 

15-35 24-35 &61 35-41 

35-39 23-35 68-92 IO-36 

9-43 74-80 22-56 49-83 

8-27 631 17-29 20-3 1 

o-12 15-19 33-70 9-43 

15-25 8-18 8-l 10 17-23 

13-21 8-37 35-63 8-37 

2-36 42-50 40-72 11-26 

o-37 2-39 o-57 O-30 

o-28 1621 17-62 2-13 

O-29 8-18 55-86 247 

2-23 14-24 2-66 O-26 

2-6 12-19 2-30 8-16 

O-100 2-80 o-1 10 O-83 

Material 

K L 

18-62 40-68 

14-43 32-53 

59-99 24-65 

14-63 39-63 

10-37 31-59 

8-42 4&57 

8-52 24-53 

lo-35 29-39 

449 44-63 

lo-37 26-37 

6-39 14-39 

841 30-39 

6-39 1 l-37 

10-12 32-76 

18-26 20-24 

17-55 22-53 

18-30 19-25 

6-23 19-34 

1 l-30 O-11 

o-14 6-39 

645 7-16 

2-11 2-14 

all 4 7-26 

13-22 13-25 

o-99 O-76 

M 

52-60 

30-37 

37-83 

3446 

23-45 

6-59 

9-72 

o-39 

4-92 

30-37 

32-37 

26-39 

33-37 

o-6 

17-25 

o-45 

8-22 

6-23 

o-4 

6-16 

16-26 

6-15 

2-29 

2-42 

O-83 

a Laboratories ordered by sum of ranks of 24-hr medians as in Table 26. 
INTERLABORATORY EYE AND SKIN COMPARISONS 

B. Eye Test-Reference Procedure 

291 

For quantitative comparisons, medians of the scores were calculated for the 6 rabbits 

treated and read for eye irritation. The scores at 24 hr, at 72 hr, and at 7 days for the 

individual rabbits as well as the medians of these totals for all 6 rabbits at each time 

period for materials A, F, G, J, K, L, M, N, and P are presented in Tables 3-l 1 for the 

24 laboratories that participated in the reference eye test. The order, from top to bottom 

in each table, is in severity of the median total score at 24 hr. Thus in Table 3, Material A, 

the highest median score at 24 hr was 50 for laboratory 29, and the lowest was 2 for 

laboratory 8; the results of laboratory 29 were, therefore, presented first and those of 

laboratory 8 last. 

TABLE 13 

RANGEOF SCORESFOR EYESOF INDIVIDUAL RABBITS-24-HR REFERENCE 

PROCEDURE" 

Range for material 

Laboratory 

No.~ 

_-~ - 

14 

29 

4. 

12 

1 

IO 

31 

22 

2 

9 

11 

23 

25 

21 

5 

19 

16 

24 

7 

13 

18 

8 

27 

30 

20 2 34 4 44 28 8 39 

40 12 53 43 29 21 7 15 

32 48 25 48 44 41 46 26 

27 29 79 20 49 24 12 9 

36 22 31 25 27 28 22 12 

24 17 20 29 34 17 53 52 

30 9 40 14 44 29 63 48 

24 11 75 31 25 10 39 35 

96 29 23 53 45 19 88 53 

17 8 49 43 27 11 7 16 

17 26 34 35 33 25 5 11 

20 11 61 6 33 9 13 25 

4 12 24 26 33 26 4 31 

34 6 34 34 2 44 6 9 

19 25 12 11 8 4 8 7 

12 4 37 34 38 31 45 29 

10 10 102 6 12 6 14 15 

8 29 28 29 17 15 17 6 

34 8 32 15 19 11 4 2 

37 37 57 30 14 33 10 10 

28 5 45 II 39 9 10 10 

29 10 31 45 9 12 9 21 

21 10 64 26 0 19 27 29 

4 7 28 8 9 12 40 2 

J 

- 

K L M 

__- 

N 

___. 

P 

__~~~ 

26 

30 

37 

7 

46 

26 

28 

25 

65 

21 

32 

19 

27 

8 

14 

7 

12 

9 

2 

20 

8 

29 

17 

4 

a Maximum minus the minimum (Table 12). 

b Laboratories ordered by sum of ranks of 24-hr medians as in Table 26. 

Variations among these total scores for individual rabbits differed considerably in the 

different laboratories. The maximum possible score for eye injury is 110. At 24 hr with 

material A, Table 3, the range in totals for individual rabbits was 4 to 100 in laboratory 2 

while at the same time period it was only 35 to 39 in laboratory 25 and 2 to 6 in laboratory 30. Similarly, the range of 2 to 110 was recorded at 72 hr in laboratory 7 (Table 3) 
292 WEIL AND SCALA 

while a range of 0 to 2 was recorded in both laboratories 19 and 30. It should be noted 

that the median for the 72-hr group in laboratory 7 was 18.5, relatively unaffected by the 

maximum score of 110. The arithmetic mean for these 6 scores would have been 3 1. 

The minimum and maximum scores for each material for each laboratory at the 24-hr 

reading period are recorded in Table 12. The overall minimums and maximums for 

each material are presented at the bottom of this table. The smallest range was 0 to 63, 

for material N. The largest range was 0 to 110, the lowest and the highest possible scores, 

for material G. Some laboratories recorded low and very high scores, e.g., laboratory 2 

had scores ranging from 0 to 100 and laboratory 16 from 4 to 110. Other laboratories 

had much smaller ranges, e.g., laboratory 5 had no score over 31 and laboratory 30 had 

no score over 42. 

TABLE 14 

RANK AND SUM OF RANKS OF RANGES LISTED IN TABLE 13 

Rank of range for material 

Laboratory 

No.” A F G J K L M N P 

14 15.5 24 13 24 4 6.5 17.5 4 9.5 

29 2 10.5 7 4.5 12 1 I 19.5 13.5 5 

4 7 120 2 4 2 4 9 3 

12 11 4 2 16 1 10 13 19.5 21 

1 4 8 16.5 15 13.5 6.5 9 15 2 

10 12.5 9 23 11.5 8 14 3 2 9.5 

31 8 17 10 18 4 5 2 3 7 

22 12.5 12.5 3 9 15 20 7 5 11 

2 1 4 22 1 2 12.5 1 1 I 

9 18.5 18.5 8 4.5 13.5 18.5 19.5 I2 12 

11 18.5 6 13 6 10 9 22 16 4 

23 15.5 12.5 5 22.5 10 21.5 I2 10 14 

25 23.5 10.5 21 13.5 10 8 23.5 6 8 

21 5.5 21 13 7.5 23 I 21 19.5 19.5 

5 17 7 24 19.5 22 24 17.5 21 16 

19 20 23 1 I 7.5 7 4 5 7.5 22 

16 21 15 1 22.5 19 23 11 13.5 17 

24 22 4 18.5 11.5 17 15 10 22 18 

7 5.5 18.5 15 17 16 18.5 23.5 23.5 24 

13 3 2 6 10 18 3 14.5 17.5 13 

18 10 22 9 19.5 6 21.5 14.5 17.5 19.5 

8 9 15 16.5 3 20.5 16.5 16 11 6 

27 14 I5 4 13.5 24 12.5 8 7.5 15 

30 23.5 20 18.5 21 20.5 16.5 6 23.5 23 

Sum of ranks 

With Without 

G G 

118 105 

85 78 

52 32b 

97.5 95.5 

89.5 73 

92.5 69.5 

74 64 

95 92 

45.5” 23.5’ 

125 II7 

104.5 91.5 

123 118 

124 103 

131 118 

168 144 

107 96 

143 142 

138 119.5 

161.5 146.5 

87 81 

139.5 130.5 

113.5 97 

113.5 109.5 

172.5 154 

a Laboratories ordered by sum of ranks of 24-hr medians as in Table 26. 

b Outside limits for 8 samples; c(,,.,,~ = 41.8 to 158.2. 

c Outside limits for 9 samples; c(,,.,,~ = 50.5 to 174.5. 

The ranges are listed in Table 13. They were ranked for each material from 1 for the 

largest range to 24 for the smallest. These ranks and their sums are presented in Table 14. 

For example, for material A, laboratory 2 had a range of 96 and was given a rank of 1, 

while laboratories 25 and 30 had ranges of 4; both were given ranks of 23.5. It was noted 
INTERLABORATORY EYE AND SKIN COMPARISONS 293 

that unusual results occurred with material G (20-volume cream peroxide). For example, other than for G, laboratory 4 had no ranks higher than 9 while the rank for G 

was 20. Similarly, laboratory 2 ranked 22 for G while it ranked 1 for 5 other samples, 

and 2 and 4 for two others. Therefore, the ranks for each laboratory were summed with 

and without that for material G. The ranks and sums of ranks for the minimum or 

maximum scores are presented in Tables 15 and 16. Again, the rank of 1 was given to the 

largest absolute value for each, 2 to the next largest, etc. A list is presented in Table 17 of 

the laboratories which had unusually low or high sums of ranks. A low sum of ranks 

indicates generally large ranges or high minimums or maximums. 

TABLE 15 

RANK, AND SUM OF RANKS, OF MINIMUM SCORE FOR EYES OF ANY 

RABBIT-24-HR REFERENCE PROCEDURE’ 

Sum of ranks 

Rank for sample 

Laboratory ___~- With Without 

No.* AFGJKLMNPG G 

14 1 2.5 10 1 3 2.5 1 5 2.5 28.5” 18.Y 

29 4.5 2.5 6.5 5 6.5 5.5 6.5 3.5 16 56.5 50 

4 3 4 22.5 13.5 1 11.5 2 1.5 2.5 61.5 39d 

12 8 8.5 16 3 6.5 4 3 1.5 1 51.5 35.5d 

1 6 7 2.5 7 11.5 7 9 16 4.5 70.5 68 

10 14.5 6 5 6 15 2.5 15.5 21 12.5 98 93 

31 4.5 10.5 14 9 15 11.5 12 11.5 12.5 100.5 86.5 

22 11.5 8.5 18 17 11.5 9 22.5 23.5 10 131.5 113.5 

2 17 12 22.5 18 21.5 1 18 13.5 22.5 146 123.5 

9 7 10.5 15 23 11.5 10 6.5 8 8 99.5 84.5 

11 13 19 6.5 20 18.5 17 5 3.5 20 122.5 116 

23 9.5 13 22.5 4 15 8 8 11.5 4.5 96 73.5 

25 2 14 1 12 18.5 19 4 18.5 10 99 98 

21 14.5 1 11 2 11.5 5.5 22.5 16 22.5 106.5 95.5 

5 I6 23 12.5 8 3 14 10 6.5 6 99 86.5 

19 22.5 16 9 13.5 5 13 22.5 6.5 16 124 115 

16 9.5 21 17 10 3 15.5 13 13.5 18.5 121 104 

24 11.5 21 8 15.5 18.5 15.5 15.5 9 14 128.5 120.5 

7 19 5 4 11 9 24 22.5 23.5 22.5 140.5 136.5 

13 22.5 24 22.5 23 24 22 15.5 16 7 176.5’ 154 

18 22.5 15 12.5 20 18.5 20.5 11 21 10 151 138.5 

8 22.5 21 2.5 20 23 23 15.5 18.5 16 162 159.5d 

27 19 17 19.5 23 21.5 20.5 19.5 21 18.5 179.5’ 160* 

30 19 18 19.5 15.5 8 18 19.5 10 22.5 150 130.5 

(1 Minimum score from Table 12. 

b Laboratories ordered by sum of ranks of 24-hr medians as in Table 26. 

c Outside limits for 9 samples; ~~~~~ = 50.5 to 174.5. 

* Outside limits for 8 samples; o(,,.,,~ = 41.8 to 158.2. 

Those with significantly low sums in 1 or more of these 3 categories were Iaboratories 

2, 4, 12, and 14, while laboratory 29 had nearly significant minimum and maximum 

sums. One of these, laboratory 4, was low in all 3 categories; thus laboratory 4 displayed 

a tendency to have unusually high ranges and to have high minimum and high maximum 
294 WEIL AND SCALA 

scores for the reference eye test. Three of the laboratories, 14, 12, and 29, had fairly consistently high minimums and maximums while laboratory 2 had high ranges and 

maximums. 

TABLE 16 

RANK, AND SUM OF RANKS, OF MAXIMUM SCORE FOR ANY RABBIT24-HR REFERENCE PROCEDURE, EYES” 

Rank for sample 

Laboratory _ ~~~~~~ -- ~~ 

No.* A F G J K L M N P 

14 5 4 16 3 3 2 4 3 4 

29 2 3 3.5 2 8 9 13.5 8 9 

4 3 1 23 5.5 1 3 2 1 3 

12 7 5 3.5 4 2 4.5 6 7 5 

1 4 6.5 5.5 8 13.5 6 7.5 19 2 

10 15 6.5 17 7 9 7 5 5 11 

31 6 15 20 17 5 9 3 4 7 

22 11 10 7 14 15 12.5 10.5 9.5 11 

2 1 8 24 5.5 6 4.5 1 2 1 

9 11 17 14.5 10.5 13.5 15.5 13.5 12 14.5 

11 17.5 12.5 9 14 11.5 12.5 13.5 12 13 

23 14 15 14.5 12 10 12.5 10.5 12 7 

25 9 15 2 16 11.5 15.5 13.5 9.5 7 

21 8 2 19 1 22 I 23 21.5 22 

5 19 18 22 18 18 21 18 15 16 

19 23 21.5 10 10.5 4 9 7.5 6 21 

16 20 23.5 1 22 16.5 19.5 20 17 20 

24 22 12.5 12 14 19 17 19 18 19 

7 13 9 8 20.5 16.5 24 24 24 24 

13 11 11 18 19 21 12.5 21 20 14.5 

18 17.5 20 13 24 7 22 17 23 18 

8 16 23.5 5.5 9 23 23 22 16 11 

27 21 19 11 20.5 24 18 16 14 17 

30 24 21.5 21 23 20 19.5 9 21.5 23 

s Maximum score from Table 12. 

0 Laboratories ordered by sum of ranks of 24-hr medians as in Table 26. 

c Outside limits for 9 samples: OL~J,~ =50.5 to 174.6. 

d Outside limits for 8 samples; a0.05 = 41.8 to 158.2. 

Sum of ranks 

With Without 

G G 

~___ .-~-~- 

44’ 2gd 

58 54.5 

42.5’ 19.5d 

44” 40.5d 

72 66.5 

82.5 65.5 

86 66 

100.5 93.5 

53 2gd 

122 107.5 

115.5 106.5 

117.5 103 

99 97 

119.5 100.5 

165 143 

112.5 102.5 

159.5 158.5d 

152.5 140.5 

163 155 

138 120 

161.5 148.5 

149 143.5 

160.5 149.5 

182.5’ 161.5d 

At the other extreme were the laboratories with unusually high sums of ranks, denoting low ranges, minimums, or maximums. As can be seen in Table 17, some of these 

laboratories were low in 2 or more of the 3 categories, some in only one. None had 

significantly high sums for the range, but laboratories 5 and 30 approached this. 

Laboratories 8, 13, and 27 had unusually high sums (consistently low values) for the 

minimums and laboratories 16 and 30 had unusual maximums. Furthermore, the 

maximums for laboratories 5, 7, 18, and 27 were quite high, indicating a trend toward 

lower than usual maximum scores. Laboratory variability will be further illustrated in 

the discussion of median scores. 
INTERLABORATORY EYE AND SKIN COMPARISONS 295 

Many other examples of unusual variation in the eye test results may be seen in the 

tables. For example, the tendency for eye healing to occur-for the scores at 72 hr and 

7 days to be lower than those at 24 hr-was toward healing in 22 of the 24 laboratories 

for material A (Table 3). However, the opposite trend occurred for laboratories 7 and 

24. The overall medians for all laboratories were 21.2, 9.8, and 2.0 at 24 hr, at 72 hr, 

and at 7 days, respectively. Those for laboratory 24 for these same periods were 17,42, 

and 57. Similarly, no healing trend for material F (Table 4) was apparent for laboratories 12 and 24 while laboratory 21 had median scores of 76,41, and 7.5. For material L 

(Table 8) the 24- and 48-hr and 7-day medians were 47,64, and 76 for laboratory 12 as 

opposed to 56, 26.5, and 7 for laboratory 2. 

TABLE 17 

SIGNIFICANT AND NEAR-SIGNIFICANT SUMSOF RANKSFOR RANGE, 

MINIMUM,• R MAXIMUM-24-HR REFERENCE PROCEDURE,EYES~ 

Range Minimum Maximum 

Laboratory 

No. 

2 

4 

14 

12 

29 

With Without 

G G 

45Sb 23.5h 

52 32b 

With Without 

G G 

61.5 39b 

28.5b 18.5& 

51.5 35.5b 

56.5 50 

With Without 

G G 

53 29b 

42.5b 19.5” 

44* 28b 

44* 40.5b 

58 

30 172.5 154 1 82.5b 

5 168 165 

7 

13 176.5b 154 

27 179.5b 16Ob 

8 1 59.Sb 

18 

16 

a Near-significant = within 10 points of pertinent 95 % limits listed. 

b With G, c10.05 limits = 50.5 to 174.5. Without G, a,,05 limits = 41.8 to 158.2. 

161.5b 

155 

149.5 

148.5 

158.5’ 

- 

It must be recalled that these median scores are those for the 50th percentile of the 6 

rabbits used and further that the score for each individual rabbit is the sum of 3 components. The maximum possible score for any eye at any period is 110; this is the sum of 

the following maximums: cornea-degree of opacity and area involved, 80; iris-congestion, injection, etc., 10; and conjunctivae-redness, chemosis, discharge, 20. Examples of how the medians of the laboratories differed in these 3 components of the 

total eye score may be seen in Table 18. Here the results of the laboratories are presented 

in the order of overall severity of action (see Table 26), which will be discussed later. 

Laboratory 14 had the lowest overall sum of ranks indicating the highest general readings for severity of action while laboratory 30 had the highest sum of ranks. In Table 18, 

for material G, different laboratories rated median cornea1 damage from 0 (laboratory 

2) to 70 (laboratory 25). Fifteen laboratories scored 5 to 10 for iris involvement, while 9 

had medians of 0. Thirteen laboratories had median conjunctival scores above 10; 

I1 had median scores of 10 or below. 
TABLE 18 

MEDIAN VALUES FOR CORNEA, IRIS, AND CONJUNCTIVA COMPONENTS OF SCORE. REFERENCE M

Laboratory 

Material G Material K 

No.“ Cornea Iris Conjunctivae Total Cornea Iris Conjunctivae Total Co

14 30 

29 60 

4 10 

12 40 

1 60 

10 30 

31 15 

22 15 

2 0 

9 40 

11 30 

23 22.5 

25 70 

21 40 

5 5 

19 40 

16 60 

24 30 

7 60 

13 30 

18 30 

8 60 

27 17.5 

30 5 

10 

7.5 

5 

10 

10 

5 

5 

5 

0 

5 

5 

5 

0 

0 

5 

0 

5 

5 

0 

0 

0 

10 

0 

0 

6 

18 

8 

14 

12 

14 

7 

11 

6 

13 

8 

7 

11 

15 

15 

8 

15 

13 

10 

6 

20 

13 

6 

6 

46 10 

83.5 20 

23 60 

65 1s 

82 0 

51 5 

28.5 20 

29 7.5 

7 2.5 

58 5 

46 0 

41 0 

82 0 

55 0 

26 5 

48 12.5 

80 0 

49 0 

70 7.5 

36 0 

50 0 

83 0 

26 0 

11 5 

10 9 29 4

5 16 39 2

5 14 79 3

5 14 34 2

5 10 14 2

0 8 13 4

0 8 28 2

2.5 10 21 2

0 9 12.5 4

0 12 20 

0 8 8 

0 11 12 

0 7 7 

0 12 12 

5 12 22 

5 17 32 

5 17 21 

5 11 16 

0 8 14.5 

0 12 12 

0 6 6 

0 4 4 

0 4 4 

0 9 13 

e Laboratories ordered by sum of ranks of 24-hr mediar,s as in Table 26. 
TABLE 19 

EYE-MEDIAN SCORE-REFERENCE PROCEDURE 

Laboratory 

No. 

Median scorea at 

___~- 

24 Hr 12 Hr 7 Days 

1 48 19 1 

2 15 7 0 

4 46.5 24 2 

5 12.5 4 2 

7 17 18.5 24.5 

8 2 0 0 

9 31 20.5 7.5 

10 17 9 5 

11 20.5 10.5 2 

12 39 17.5 6 

13 24.5 5 2 

14 45 29.5 0 

16 22 14 2 

18 20.5 5 0 

19 5 0 0 

21 10 6.5 2.5 

22 25 8 0 

23 23.5 9 4 

24 17 42 57 

25 36 17 3 

21 16.5 7.5 0 

29 50 38 10.5 

30 5 0 0 

31 30 14 0 

24 Hr 72 Hr I Days 24 Hr 72 Hr 

- 

46 

49 

64 

24 

47 

10 

31 

49.5 

21 

43 

15.5 

60 

16 

17.5 

16 

76 

35.5 

33 

15.5 

28 

24 

64 

15 

30.5 

~-~ ___-~ __~ -~~ 

46 14.5 82 74.5 

46 10 7 2 

58 34.5 23 15 

6 3 26 17.5 

43.5 20.5 70 83 

15 7 83 81 

24.5 1 58 53 

27 7 51 32.5 

22.5 19 46 14 

58 50.5 65 47 

14 4 36 32 

56 45 46 50 

18 10 80 46 

16 8.5 54 5.5 

15 8 48 41 

41 1.5 55 60.5 

35 22 29 14 

23 6 41 45 

34 27.5 49 52 

14 2 82 66 

16.5 2 26 46.5 

55.5 28 83.5 83 

26 9.5 11 8 

31.5 24 28.5 23 

7 D

3

1

8

7

2

6

3

4

1

4

4

1

5

2

3

5

1

0 Maximum possible score = 110. 
TABLE 19-Continued 

Material 

K L M 

Median score” at 

Laboratory ___ ___- 

-__. .___ 

No. 24 Hr 72 Hr 7 Days 24 Hr 72 Hr 7 Days 24 Hr 72 Hr 7 Days 

1 

2 

4 

5 

7 

8 

9 

10 

11 

12 

13 

14 

16 

18 

19 

21 

22 

23 

24 

25 

27 

29 

30 

31 

- 

14 11 0 39 44 14.5 30.5 20 1 

12.5 21.5 11 56 26.5 7 51 25.5 4.5 

79 68 32 52 27 27 77 34.5 18.5 

22 42 41.5 22 19.5 28.5 22 15.5 2 

14.5 14.5 10 5.5 5.5 3 2 2 0 

4 11.5 0 8 15 6.5 11.5 5 0 

20 19 5 32 31 20 33 18 17 

13 8.5 2 52.5 45.5 18 50 44 14 

8 8 3 35 35 21.5 35 29.5 2 

34 20 12 47 64 76 46 44 17 

12 5 1 12 5 2 16 11 2 

29 19.5 4 58 57 37 59 52 25.5 

21 30.5 37.5 22 26.5 28 15 13.5 0 

6 13 9 10 9 5.5 17.5 6 0.5 

32 16 9 30 29.5 10.5 13.5 0 0 

12 6 0 47.5 28.5 28 6 6 0 

21 9.5 1 32.5 23 20.5 33.5 32.5 1 

12 8 2 35.5 35.5 24.5 30 2.5 0 

16 42 40 21 17 9 21 33 I 

7 11.5 2 35 35 26.5 34 30 2 

4 4 0 20 21 0 24 5.5 0 

39 45 26.5 43 39.5 37 33 27 13 

13 17.5 23 14 9.5 19 10 0 0 

28 37 29 42 33 29 55 32.5 2.5 

24Hr 72

-~. ~~ 

11 

32 

52 2

22 1

2 

10 

21.5 1

40.5 1

33 2

39 4

16 1

55 3

9 

5 

32 1

6 1

30 2

11 

17 1

10.5 

2 

33 3

15 1

31 

a Maximum possible score = 110. 
INTERLABORATORY EYE AND SKIN COMPARISONS 299 

For material K, 11 laboratories had median scores of 0 for cornea1 damage at 24 hr, 

while laboratory 4 scored 60 for this. Thirteen laboratories had 0 for iris injury; 11 rated 

some discernible damage to the iris. Sixteen laboratories found iris damage from 

material L, 8 found none; 14 had conjunctival scores above 10; 10 laboratories had 

medians below 10. 

TABLE 20 

EYE-RANKS AND SUMS OF RANKS-24-HR MEDIAN 

Laboratory 

No. 

Material 

A F G J K L M N P 

With Without 

G G 

1 2 8 3.5 8 13 8 12 16.5 2.5 73.5 70 

2 19 6 24 6 16 2 4 7.5 11 95.5 71.5 

4 3 2.5 22 3 1 4 1 2 1 39.5” 17.5” 

5 20 16.5 20.5 14 7 16.5 15 11 10 130.5 110 

7 16 7 6 21 12 24 24 23.5 24 157.5 151.5 

8 24 24 2 15 23.5 23 21 19 12 163.5 161.5* 

9 7 12 8 10 10 13.5 10.5 12 14 97.0 89 

10 16 5 11 9 14.5 3 5 3 13 79.5 68.5 

11 13.5 15 14.5 13 20 10.5 7 5.5 7 106.0 91.5 

12 5 9 7 5 3 6 6 4 2.5 47.5” 40.5* 

13 10 21.5 17 24 18 21 18 14 15 158.5 141.5 

14 4 4 14.5 2 5 1 2 1 4 37.5” 23* 

16 12 19.5 5 19 8.5 16.5 19 20 18 137.5 132.5 

18 13.5 18 10 22 22 22 17 22 16 162.5 152.5 

19 22.5 19.5 13 16.5 4 15 20 7.5 19 137.0 124 

21 21 1 9 1 18 5 23 21 22 121.0 112 

22 9 10 18 11 8.5 12 9 10 6 93.5 75.5 

23 11 11 16 7 18 9 13 16.5 8 109.5 93.5 

24 16 21.5 12 16.5 11 18 16 13 20.5 144.5 132.5 

25 6 14 3.5 18 21 10.5 8 18 17 116.0 112.5 

27 18 16.5 20.5 23 23.5 19 14 23.5 20.5 178.5” 158 

29 1 2.5 1 4 2 7 10.5 5.5 5 38.5” 37.5* 

30 22.5 23 23 20 14.5 20 22 15 23 183.0” 160* 

31 8 13 19 12 6 13.5 3 9 9 92.5 73.5 

Sum of ranks 

a Outside limits; q,.05 = 50.5 to 174.6. 

b Outside limits; CQ.,,~ = 41.8 to 158.2. 

The median scores are recorded in Table 19 for eye injury for each of the 24 laboratories for the 9 pertinent materials for the 3 time periods in which reactions were noted. 

These medians were ranked in Tables 20,21, and 22 for each sample at each time period 

from 1 for the highest score, 2 for the next highest, and so forth. 

The coefficients of rank correlation, all positive, between median scores for each of 

the laboratories for the 9 materials at the 3 reading periods are given in the accompanying tabulation. 
300 WEIL AND SCALA 

Material 

- 

A 

F 

G 

J 

K 

L 

M 

N 

P 

24-Hr 

7&r 

24-Hr 

OS. 

7-day 

72-HI 

7-Y& 

Median of median scores; 

all the laboratories 

24 72 

Hr Hr 

7 

Days 

0.764” 0.298 

0.753” 0.363 

0.772“ 0.558 

0.467 0.015 

0.736” 0.631 

0.802b 0.577 

0.832* 0.842’ 

0.799” 0.745” 

0.678” 0.702” 

0.584 21.2 9.8 2.0 

0.776” 30.8 26.5 9.8 

0.814’ 48.5 46.8 21.8 

0.661 28.2 29.5 16.0 

0.888* 14.2 15.2 7.0 

0.643 32.8 27.8 20.2 

0.829’ 30.2 19.0 1.5 

0.632 19.2 10.8 0.8 

0.662 20.8 7.8 0.0 

n Two-tailed critical values for 0.05 > P > 0.01 = 0.666. 

b Two-tailed critical values for 0.01 > P > 0.001 = 0.798. 

c Two-tailed critical values for P -e 0.001 = 0.892. 

These correlations indicate that with some materials, e.g., M, N, and P, readings at 

24 hr would be sufficient. The later readings, at 72 hr and at 7 days, were well correlated 

with the 24-hr readings. Note that at 7 days the overall median scores for M, N, and P 

were close to zero. For 8 of the 9 materials (all but J), the 72-hr readings were correlated 

with those at 24 hr. Note that, generally, the coefficients of correlation between the 7-day 

and 72-hr readings were as great as or greater than those between the 7-day and 24-hr 

readings. With the good correlation between scores at 24 and at 72 hr, there does not 

appear to be sufficient reason to read the reactions at 72 hr. 

Generally, the ranking of materials, within any laboratory, was similar whether the 

24-hr median or the median of all 3 periods was used. In 19 of the 24 laboratories using 

the reference procedure, significant rank correlation occurred (Table 56). In the 5 

laboratories with nonsignificant correlation, only 2, laboratories 5 and 18, were quite 

low. Various reasons for this can be determined on scrutiny of the data on individual 

samples. For example, the trend for increased injury with time for material K in 

laboratory 5 was abnormal, compared to most other laboratories, and was also a prime 

reason for the poor intralaboratory correlation between 24-hr median and median of 

medians. 

The ranks for each laboratory were summed for the 9 pertinent samples, as well as 

for these without material G (for the reasons previously discussed). Tables 20, 21, 22, 

and 23 give these ranks and their sums at 24 hr, at 72 hr, at 7 days, and for the median of 

the scores for these 3 time periods. The statistically significant sums (P c 0.05) and those 

close to significance-arbitrarily selected as sum of ranks within 10 points of the critical 

sums-are presented in Table 24. 

Laboratories 12, 14, and 29 had consistently low sums of ranks at all time periods, 

while laboratory 4 had a very low sum of ranks only at 24 hr. This indicates that this 

latter laboratory recorded unusually high eye injury scores at 24 hr, but that their scores 

at 48 hr and at 7 days were not unusual compared to the scores reported by the other 

laboratories. 
INTERLABORATORY EYE AND SKIN COMPARISONS 301 

Similarly, laboratory 27 had consistently high sums of ranks at all time periods, indicating low eye injury scores. Similar trends were apparent for laboratories 8 and 18, 

while laboratory 7 was close to significance and laboratory 30 was statistically significant only at 24 hr; laboratory 13 approached significance only in the median of the 

medians category. 

TABLE 21 

EYE-RANKS AND SUMS OF RANKS-72-HR MEDIAN 

Sum of ranks 

Material 

Laboratorv -.-.-----___- ~~ ___ With Without 

A F G J K L M N P G G 

- 

No. 

1 6 5.5 4 15 17 4 12 19.5 4 87.0 83.0 

2 17 5.5 24 2 7 14.5 11 16 22 119.0 95.0 

4 4 1.5 20 18 1 13 4 5 5 71.5 51.5 

5 21 24 19 14 3.5 18 14 11 10 134.5 115.5 

7 7 7 1.5 23 13 23 22 23.5 19 139.0 137.5 

8 23 20.5 3 19 15.5 20 20 19.5 17.5 158.0 155.0 

9 5 14 8 16.5 10 10 13 8.5 22 107.0 99.0 

10 13.5 12 16 10 19 3 2.5 10 14 100.0 84.0 

11 12 16 5 8 20.5 7.5 9 6 15.5 99.5 94.5 

12 8 1.5 11.5 3.5 8 1 2.5 I 1 38.0” 26.5b 

13 19.5 22.5 17 3.5 23 24 16 13.5 12 151.0 134.0 

14 3 3 10 I 9 2 1 2 2 33.0” 23.0b 

16 10.5 17 14 21 6 14.5 15 17.5 9 124.5 110.5 

18 19.5 19 23 22 14 22 17.5 22 15.5 174.5 151.5 

19 23 20.5 11.5 20 12 11 23.5 12 22 155.5 144.0 

21 18 8 7 12 22 12 17.5 13.5 22 132.0 125.0 

22 15 9 21 11 18 16 6.5 4 3 103.5 82.5 

23 13.5 15 15 13 20.5 6 21 23.5 13 140.5 125.5 

24 1 10 9 7 3.5 19 5 8.5 6 69.0 60.0 

25 9 22.5 6 16.5 15.5 7.5 8 17.5 11 113.5 107.5 

27 16 18 13 24 24 17 19 21 17.5 169.5 156.5 

29 2 4 1.5 5 2 5 10 3 8 40.5” 39.0b 

30 23 13 22 9 11 21 23.5 7 22 151.5 129.5 

31 10.5 11 18 6 5 9 6.5 15 7 88.0 70.0 

’ Outside limits; Q.,,~ = 50.5 to 174.6. 

b Outside limits; CQ.~~ = 41.8 to 158.2. 

All of the laboratories that showed significant or near-significant divergence on the 

median basis (Table 24) also showed significant or near-significant divergence on the 

range, minimum, or maximum basis (Table 17). While 3 additional outlying laboratories are in the latter table, the best method of discrimination of divergent laboratories 

is on the basis of their medians. 

The median scores (for any material in each laboratory) that were the lowest or highest 

are presented, along with the median of the medians, in Table 25. As with the range 
302 WEIL AND SCALA 

between individual rabbits, previously discussed, the range in median readings in some 

laboratories was extremely low. For example, the range from the maximum to minimum medians for laboratory 5 was only 4 (from 22 to 26) as contrasted to a range of 8 1 

(from 2 to 83) for the medians of laboratory 8. The range for 75 ‘4 of the laboratories 

was 30 or more; therefore, those laboratories that had small ranges in sample medians, 

especially laboratories 5, 30, and 22, were unusual. 

TABLE 22 

EYE-RANKS AND SUMS OF RANKS-Y-DAY MEDIAN 

Laboratory 

No. A F G J K L M N P 

With Without 

G G 

1 15 10 9 23.5 22.5 16 14 19 18 147.0 138.0 

2 20 11.5 23.5 15 9 19 7 8 18 131.0 107.5 

4 12 3 22 17 4 8 2 5 5 78.0 56.0 

5 12 21 15 5 1 5 10.5 7 4 80.5 65.5 

7 2 8 1 18 10 22 20.5 19 18 118.5 117.5 

8 20 17.5 2 20 22.5 20 20.5 19 18 159.5 157.5 

9 4 24 21 13.5 13 13 3.5 3.5 18 113.5 92.5 

10 6 17.5 13 10 17 15 5 6 18 107.5 94.5 

11 12 9 3 2 15 11 10.5 9.5 7.5 79.5 76.5 

12 5 1 11 9 8 1 3.5 3.5 1 43.0” 32.0b 

13 12 20 23.5 8 19.5 23 10.5 9.5 10 136.0 112.5 

14 20 2 6.5 7 14 2.5 1 1 3 57.0 50.5 

16 12 11.5 16 22 3 6.5 20.5 19 18 128.5 112.5 

18 20 14 18 13.5 11.5 21 16 13 6 133.0 115.0 

19 20 15 8 16 11.5 17 20.5 11.5 18 137.5 129.5 

21 9 16 6.5 20 22.5 6.5 20.5 19 18 138.0 131.5 

22 20 7 19 11 19.5 12 14 19 2 123.5 104.5 

23 7 19 17 20 17 10 20.5 19 10 139.5 122.5 

24 1 5 4.5 4 2 18 14 19 18 85.5 81.0 

25 8 22.5 12 12 17 9 10.5 11.5 18 120.5 108.5 

27 20 22.5 10 23.5 22.5 24 20.5 19 18 180.0” 1 70.0b 

29 3 4 4.5 3 6 2.5 6 2 10 41.0” 36.5b 

30 20 13 20 1 7 14 20.5 19 18 132.5 112.5 

31 20 6 14 6 5 4 8 19 7.5 89.5 75.5 

Material 

Sum of ranks 

0 Outside limits; OL~.~~ =50.5 to 174.6. 

b Outside limits; o(o.~~ = 41.8 to 158.2. 

Also presented in Table 25 are the materials associated with minimum, maximum, and 

median values for each laboratory. It is notable that, in 15 of the 24 laboratories, 

material G was the material associated with their maximum median. Contrariwise, 

material G was the minimum for laboratories 2 and 4. In 13 laboratories, materials K 

and/or N were ranked minimum. However, they were ranked maximum by laboratories 

4 and 30. Consistency in the ability to discern the relative degree of irritancy of materials 

is important if the test is to be useful. The data in Table 25 clearly indicate that, with 
INTERLABORATORY EYE AND SKIN COMPARISONS 303 

TABLE 23 

EYE-RANKS AND SUM OF RANKS-MEDIAN OF MEDIANS 

Sum of ranks 

Laboratory __ 

Material 

-__- ~- With Without 

No. AFGJKLMNPG G 

1 6 5.5 4 14 14 5 12 18 4 82.5 78.5 

2 17 5.5 24 4.5 13 14.5 10 15 20 123.5 99.5 

4 4 1 20 16.5 1 13 4 5 5 69.5 49.5 

5 21 24 19 13 2 17 14 11 9 130.0 11l.U 

7 7 7 1.5 22 12 23 22 24 19 137.5 136.0 

8 24 23 3 18 23.5 22 20 19 17 169.5 166.5* 

9 5 13 8 15 8 10 13 7.5 21 100.5 92.5 

10 13.5 12 16 8 17 3 3 9.5 14 96.0 80.0 

11 12 15 5.5 6 18.5 7.5 8 6 15.5 94.0 88.5 

12 8 4 11.5 3 6 1 2 1 1 37.5” 26.0* 

13 19.5 21.5 17 23 22 24 16 13 12 168.0 151.0 

14 3 2 10 1 7 2 1 2 2 30.0” 20.0* 

16 10.5 17.5 13 20 4 14.5 15 16.5 8 119.0 106.0 

18 19.5 17.5 22 21 16 21 17.5 21 15.5 171.0 149.0 

19 22.5 19.5 11.5 19 11 11 23 12 22 151.5 140.0 

21 18 8 7 9.5 21 12 17.5 23 23 139.0 132.0 

22 15 9 21 9.5 15 16 5.5 4 3 98.0 77.0 

23 13.5 14 14 11.5 18.5 6 21 22 13 133.5 119.5 

24 1 11 9 4.5 10 19 11 7.5 10 83.0 74.0 

25 9 21.5 5.5 16.5 20 7.5 7 16.5 11 114.5 109.0 

27 16 16 15 24 23.5 18 19 20 18 169.5 154.5 

29 2 3 1.5 2 3 4 9 3 7 34.5” 33.p 

30 22.5 19.5 23 7 9 20 24 9.5 24 158.5 135.5 

31 10.5 10 18 11.5 5 9 5.5 14 6 89.5 71.5 

’ Outside limits; ao.05 = 50.5 to 174.6. 

* Outside limits; ~,.~s = 41.8 to 158.2. 

TABLE 24 

SIGNIFICANT AND NEAR-SIGNIFICANT SUMS OF RANKS FOR 

MEDIAN SCORE-EYE REFERENCE TE.W 

Median of 

24-Hr 48-Hr 7-Day medians 

____- --~ 

Laboratory With Without With Without With Without With Without 

No. G G G G G G G G 

33.0* 23.0* 

.~ 

14 37.5* 23.0* 57.0 50.5 30.0* 20.0* 

29 38.5* 37.5* 40.5b 39.0* 41.0* 36.5* 34.5* 33.0* 

4 39.5* 17.5b 51.5 

12 47.56 40.5* 38.0* 26.5* 43.0* 32.0* 37.5* 26.0b ~__ ~- 

13 

.___ 

168.0 151.0 

7 151.5 

18 152.5 174.5 151.5 171.0 149.0 

8 161.5” 148.2 157.5 169.5 166.5* 

27 178.5* 158 169.5 156.5 180.0b 170.0b 169.5 154.5 

30 183.0* 160.0* 

’ Near-significant = within IO points of pertinent 95 % limits listed. 

b With G; czo.05 limits = 50.5 to 174.5. Without G; cz0,05 limits =41.8 to 158.2. 
304 WEIL AND SCALA 

this test, certain materials are rated severely irritating by some laboratories and relatively non-irritating by others. The intralaboratory ranking of samples will be further 

discussed in the Results sections D, E, and F. 

The statistical parameters associated with the ranks of the 24-hr medians are summarized in Table 26. The laboratories are listed in order of lowest to highest sum of ranks, 

i.e., in order of those that read the highest, or most severe, to those with the lowest, or 

least severe, reactions. The 25th and 75th percentiles, Qi and Qj, are indications of 

variability, while the median, Q2, is an efficient measure of the midpoint. These are also 

presented in Table 26 and in Fig. 1. The measure, semi-interquartile range (SIQR), 

TABLE 25 

EYE: MAXIMUM-, MEDIAN-, AND MINIMUM-MEDIAN SCORES FOR ANY MATERIAL, 

%-HR REFERENCE METHOD 

Median scores Materials with these median scores 

Laboratory -~ ~~ -~ -__- __ 

No. Maximum Median Minimum Range” Maximum Median Minimum 

1 82 32.8 11 71 G 

2 56 19 7 49 L 

4 79 52 23 56 K 

5 26 22 22 4 GL 

7 70 7.8 2 68 G 

8 83 9 2 81 G 

9 58 26.5 18.5 39.5 G 

10 52.5 27 13 39.5 L 

11 46 27 8 38 G 

12 65 40 34 31 G 

13 36 13.8 7 29 G 

14 60 45.5 29 31 F 

16 80 15.5 9 71 G 

18 54 10.5 5 49 G 

19 48 14.8 5 43 G 

21 79 8 4 75 J 

22 35.5 29.5 21 14.5 F 

23 41 25.2 11 30 G 

24 49 16.5 10.5 38.5 G 

25 82 18 7 75 G 

27 26 10 2 24 G 

29 83.5 36 30.5 53 G 

30 15 10.5 2 13 F,N 

31 55 28.5 26 29 M 

J, M N 

P,A G 

LN G 

KLM,N K,L,M,N 

I,L M,N 

F+N,L A 

A+F,N P 

J,P K 

F,P K 

J,A+N K 

F,K+L J 

GA K 

F, M N 

J, L N 

F, M A 

A,M+N P 

N+P,G K 

P,A N 

A+N,K P 

P,J K 

P,J N 

K,M+N P 

GM P 

G,J P 

4 (Maximum-minimum). 

(Q3-Q,)/2, was extremely large for some laboratories; it was higher than 5 for laboratories 2,7, and 21. For 75 % of the laboratories the SIQR was 4.8 or less-the lower this 

measure, the greater the consistency in relative rank for the 9 samples as compared 

with the other laboratories. For example, laboratory 4 had the lowest SIQR, 1.2. This 

laboratory ranked 1 to 4 on 8 of the 9 samples; material G was the outlier. By contrast, 
TABLE 26 

EYE REFERENCE METHOD PARAMETERS 

Laboratory Sum of ranks 

No. and 

Web With G Without G 

14c 37.5’ 23.0d 

29C 38.5’ 37.56 

4c 39.5’ 17.F 

12T 47.5” 40.5d 

1T 73.5 70.0 

1oc 79.5 68.5 

311 92.5 73.5 

22c 93.5 75.5 

2G 94.5 71.5 

91 97.0 89.5 

111 106.0 91.5 

23T 109.5 93.5 

251 116.0 112.5 

21G 121.0 112.0 

5c 130.5 110.0 

19c 137.0 124.0 

16T 137.5 132.5 

24T 144.5 132.5 

71 157.5 151.5 

13T 158.5 141.5 

18C 162.5 152.5 

8T 163.5 161.5d 

271 178.5’ 158.0 20.5 17.2 23.2 3.0 14 to 23.5 

3oc 183.0’ 160.0d 22.0 17.5 23.0 2.8 14.5 to 23 

QZ 

Median 

4.0 1.5 

4.0 1.5 

2.5 1.0 

5.0 3.5 

8.0 3.0 

9.0 4.0 

9.0 7.0 

10.0 8.8 

7.5 5.0 

10.5 9.0 

13.0 7.0 

11.0 8.5 

14.0 7.0 

18.0 3.0 

15.0 10.5 

16.5 10.2 

18.0 10.2 

16.0 12.5 

21.0 9.5 

18.0 14.5 

18.0 14.8 

21.0 13.5 

Rank 

SemiQ1 

interquartile 

QS range 

4.5 1.5 

6.2 2.4 

3.5 1.2 

6.5 1.5 

12.5 4.8 

13.8 4.9 

13.2 3.1 

11.5 1.4 

17.5 6.2 

12.8 1.9 

14.8 3.9 

16.2 3.8 

18.0 5.5 

21.5 9.2 

18.2 3.8 

19.8 4.8 

19.2 4.5 

19.2 3.4 

24.0 7.2 

21.2 3.4 

22.0 3.6 

23.8 5.2 

- 

Range 

1 to 14.5 

1 to 10.5 

1 to 22 

2.5 to 9 

2 to 16.5 

3to16 

3 to 19 

6to18 

2 to 24 

7 to 14 

5.5 to 20 

7to18 

3.5 to 21 

1 to 23 

I to 20.5 

4 to 22.5 

5 to 20 

11 to 21.5 

6 to 24 

10 to 24 

10 to 22 

2 to 24 

a Ranks of 24-hr medians. 

b See Table 1. 

c Outside limits; t(0.05 = 50.5 to 174.6. 

d Outside limits; CQ.~~ = 41.8 to 158.2. 
306 WEIL AND SCALA 

laboratory 21 had a SIQR of 9.2; its rank for 2 samples was 1 while for 4 materials it 

ranked 21 or higher (out of the 24 laboratories and, therefore, the 24 possible ranks). 

There is no significant correlation between relative sum of ranks for median score at 

24 hr and the SIQR at that time. Ranking the latter, for the 21 laboratories that ran 

both the eye and skin tests, from 1 for the lab with the largest SIQR to 21 for that with 

the smallest, the coefficient of rank correlation was -0.324. However, the correlation 

coefficient between the severity-of-action rank and the rank for the size of the range 

between the maximum and minimum score for the eyes of individual rabbits was 

+0.606. Therefore, the laboratories that tended to read low in severity of reaction also 

tended to have lower variability between the readings for individual rabbits, 

-7T 

20- 

18- 

16- 

14L 

5 2 12- 

10- 

abRANK 

1 Ql FIRST QUARTILE 

2 Qz SECOND QUARTILE 

3 43 THIRD QUARTILE 

3 

1 

3 ‘1 

I I I i ?j 

? 

[I 

EYE 

1 

b-a0 o) FIDUCIAL LIMITS 4 

I I I I, I I I I I I I I ,I I I I I 

10 2" 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 

SUM OF RANKS 

FIG. 1. Sum of ranks, median, and variability-Eye, 24-hr reference procedure. 

It is notable, and probably to be expected, that the relative position of the laboratories in sum of ranks (or median score) was generally unrelated to the type of laboratory. Consultant laboratories (C) were in 3 of the 4 lowest and 2 of the 4 highest sums of 

ranks; 38x, of the participating laboratories were C. One toilet goods or cosmetic 

laboratory (T) was in the lowest and 1 was in the highest 4; the other high sum-of-ranks 

laboratory was a food or industrial chemical company (I). In variability, 3 of the 4 lowest 

SIQRs were associated with a C and one with a T laboratory. Two of the laboratories 

with unusually high variability in rank in relation to the other laboratories (high SIQRs) 

were I and 2 were governmental (G)-the only 2 governmental laboratories among the 

24 participants in the eye test. 
INTERLABORATORY EYE AND SKIN COMPARISONS 

C. Skin Test-Reference Procedure 

307 

The total irritation scores, a summation of the erythema, edema, and necrosis reactions noted at 24 hr plus those at 72 hr for each rabbit, of the materials E, F, G, I, J, 

K, L, M, N, and 0 are presented in Tables 27-36. The order, from top to bottom in each 

table, is in severity of the primary irritation (PI) score for that material. The PI is the 

average skin irritation score for the 8 rabbits used for each material: the higher the 

score, the more severe the reaction. As for the eye test, there was considerable variation 

TABLE 21 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND 

PRIMARY IRRITATION SCORES WITH ISOPROPYL MYRISTATE (MATERIAL E) 

Laboratory - 

No. 1 2 3 

13 2 6 9 

2 4 4 8 

11 5 6 6 

14 3 4 5 

5 5 5 5 

19 3 3 4 

25 2 2 3 

8 2 2 3 

31 0 0 3 

7 2 3 3 

9 1 2 2 

24 1 2 2 

26 1 1 1 

12 0 1 2 

10 0 1 1 

4 0 0 1 

22 0 0 0 

23 0 0 0 

30 0 0 0 

18 0 0 0 

21 0 0 0 

21 0 0 0 

Ordered rabbit No.” 

4 

-~ 

11 

8 

6 

5 

5 

5 

4 

3 

4 

4 

3 

2 

1 

2 

2 

1 

1 

0 

0 

0 

0 

0 

- 

5 6 7 

11 15 19 

9 9 9 

6 7 7 

6 7 7 

6 6 6 

5 6 7 

4 5 5 

4 4 5 

4 5 6 

4 4 4 

4 4 4 

3 3 3 

2 3 3 

3 3 3 

2 2 3 

2 2 2 

1 1 2 

1 1 1 

1 1 2 

0 0 0 

0 0 0 

0 0 0 

No. 

with 

8 necrosis 

-b 4b 

9 0 

7 0 

10 0 

7 0 

8 0 

9 1 

I 0 

8 0 

5 0 

4 0 

4 0 

8 0 

4 0 

4 0 

3 0 

2 0 

4 0 

2 0 

1 0 

1 0 

0 0 

Primary 

irritation 

score 

5.2 

3.8 

3.1 

2.9 

2.8 

2.6 

2.1 

1.9 

1.9 

1.8 

1.5 

1.2 

1.2 

1.1 

0.9 

0.7 

0.4 

0.4 

0.4 

0.1 

0.1 

0.0 

’ Rabbits ordered by degree of severity of reaction. 

b One rabbit died. 

among the laboratories between the total scores for individual rabbits. The minimum 

and maximum score for each laboratory for each material is presented in Table 37 and 

the range between these scores in Table 38. The laboratories are listed in order of highest 

to lowest PI score, to be discussed later. The maximum possible total score for a rabbit, 

either for the 24- or for the 72-hr reading, is the sum of maxima of 8 for erythema, 8 for 

edema and 30 for necrosis. All except 2 of the laboratories recorded minimum scores of 

zero; these 2 had minimums of 1. The maximum score for the laboratories, however, 

varied considerably-from 6 for laboratory 21 to 46 for 4 laboratories: 11, 12, 13, and 

14 
308 WEIL AND SCALA 

With the minimums being practically zero, the ranges of scores are practically synonymous with the maximums (Table 38). These ranges were ranked from 1 to 22, as 22 

laboratories participated in the reference skin test; the rank of 1 was given, for each 

material, to the laboratory with the largest range, 2 to the next largest, etc. Therefore, a 

relatively low sum of ranks indicates consistently high ranges, high variability between 

minimums and maximums, or high irritation scores. 

TABLE 28 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND 

PRIMARY IRRITATION SCORES WITH 46 % AQUEOUS TRIETHANOLAMINE 

LAURYL SULFATE (MATERIAL F) 

Laboratory - 

No. 1 

12 21 

31 31 

2 21 

13 20 

25 4 

10 23 

23 7 

11 6 

22 8 

14 5 

9 6 

26 6 

8 2 

27 5 

24 5 

19 6 

5 6 

4 3 

7 2 

30 1 

18 0 

21 0 

Ordered rabbit No.” 

2 3 4 5 

29 30 35 43 

31 31 31 32 

24 25 28 33 

23 23 25 28 

6 19 20 40 

23 24 26 26 

13 14 27 28 

8 9 10 21 

14 15 15 17 

6 10 14 18 

12 14 15 16 

8 9 9 11 

6 9 10 11 

5 7 8 8 

7 8 8 8 

6 7 7 8 

6 6 7 8 

3 4 4 5 

2 4 4 4 

2 3 3 3 

0 0 0 0 

0 0 0 0 

6 7 

-__ 

46 46 

32 33 

33 35 

34 46 

43 43 

30 31 

28 30 

32 36 

28 28 

20 20 

16 16 

11 12 

11 12 

9 10 

9 9 

8 9 

8 8 

6 6 

5 6 

4 4 

1 1 

0 0 

No. 

__- with 

8 necrosis 

---__~ ~ 

46 8 

33 8 

38 8 

-b 7* 

44 6 

31 8 

30 5 

44 4 

32 8 

22 6 

16 0 

13 0 

13 0 

12 0 

9 0 

10 0 

11 0 

6 0 

6 0 

5 0 

6 0 

0 0 

Primary 

irritation 

score 

18.5 

15.9 

14.8 

14.2 

13.7 

13.4 

11.1 

10.4 

9.8 

7.2 

6.9 

4.9 

4.6 

4.0 

3.9 

3.8 

3.8 

2.3 

2.1 

1.6 

0.5 

0.0 

0 Rabbits ordered by degree of severity of reaction. 

* One rabbit died. 

The significant, and near-significant, sums of ranks are presented in Table 39. One 

laboratory, number 13, had a significantly low sum of ranks. With 8 of the 10 materials, 

laboratory 4 ranked 6th or lower of the 22 laboratories. While 3 other laboratories 

(11,12, and 14) had nearly significantly low sums of ranks, only one (21) was at or near 

significance for high sum. The ranges were the highest, or tied with other laboratories 

for the highest, for 9 of the 10 pertinent materials. Examination of the scores of the 

individual rabbits for each sample, except that for M (Tables 27-33,35, and 36) shows 

that laboratory 21 had scores of zero for every rabbit for each of the 9 materials. Even 
INTERLABORATORY EYE AND SKIN COMPARISONS 309 

with material M, only 3 of the 8 spots had minimal reactions, 1. Thus of the 80 spots 

(10 materials, 8 rabbits each) 77 were completely negative. 

As mentioned earlier, the total skin irritation scores are the sums of those for 

erythema, edema, and necrosis. The total scores for the 8 rabbits for these 3 components 

at the 2 time periods (24 and 72 hr) for 2 materials, F and K, are presented in Table 40 as 

an example of the variation between laboratories. The maximum total scores for the 8 

rabbits for either time period are 32 for erythema, 32 for edema, and 120 for necrosis. 

TABLE 29 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND 

PRIMARY IRRITATION SCORES WITH 20-VOLUME CREAM PEROXIDE (MATERIAL G) 

Laboratory 

No. 

31 

13 

9 

26 

12 

14 

10 

11 

5 

19 

8 

25 

24 

23 

22 

2 

4 

30 

27 

7 

18 

21 

1 

0 

2 

2 

1 

2 

2 

1 

0 

0 

1 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

- 

2 

2 

3 

2 

4 

2 

2 

1 

0 

1 

1 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Ordered rabbit No.” 

3 

5 

4 

4 

5 

3 

3 

2 

1 

2 

1 

1 

1 

0 

0 

1 

0 

0 

0 

0 

0 

0 

0 

4 5 6 7 

___--~ 

6 6 8 19 

4 7 10 16 

5 5 8 8 

5 5 6 6 

4 4 5 6 

4 4 4 5 

2 3 4 4 

2 2 3 3 

2 2 3 3 

1 2 2 4 

1 2 2 3 

1 1 2 2 

1 1 2 2 

0 0 1 2 

1 1 1 1 

0 0 1 1 

0 0 0 1 

0 0 0 1 

0 0 0 0 

0 0 0 0 

0 0 0 0 

0 0 0 0 

No. 

with 

8 necrosis 

20 2 

-b 2” 

8 0 

8 0 

8 0 

7 0 

5 0 

8 0 

4 0 

5 1 

3 0 

3 0 

2 0 

3 0 

2 0 

1 0 

1 0 

1 0 

1 0 

0 0 

0 0 

0 0 

Primary 

irritation 

score 

4.1 

3.3 

2.6 

2.5 

2.1 

1.9 

1.4 

1.2 

1.1 

1.1 

0.8 

0.6 

0.5 

0.4 

0.4 

0.2 

0.1 

0.1 

0.1 

0.0 

0.0 

0.0 

a Rabbits ordered by degree of severity of reaction. 

b One rabbit died. 

For material F, laboratory 21 had scores of 0, 0, and 0 and laboratory 18 scores of 1, 1, 

and 0 at 24 hr as compared with 28,25, and 85 for laboratory 12 and 28,26, and 80 for 

laboratory 3 1. Similar variability is apparent at 72 hr and for both time periods for 

material K. Recovery was apparent (lower scores) at 72 hr in some laboratories, while 

others had much more severe reaction at the latter than at the former period; e.g., 

laboratory 23 had scores of 0 to 75 (material F) and 0 to 120 (material K) for necrosis 

at 24 and 72 hr, respectively. Differences such as these for erythema, edema, and 

necrosis, as well as for the 2 time periods, should be remembered; the primary irritation 
310 WEIL AND SCALA 

scores, to be discussed hereafter, are summations of all of these and, therefore, mask 

these individual variations. 

Note also, in Table 40, as well as in Tables 27-36, that many laboratories never recorded scores for necrosis. Therefore, the primary irritation scores are presented in 2 

manners-with and without the necrosis component-to indicate whether absence of 

such scoring affected the interlaboratory ranks. 

TABLE 30 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND PRIMARY 

IRRITATION SCORES WITH TRIETHANOLAMINE (MATERIAL 1) 

Laboratory -~- 

No. 1 

13 2 

7 2 

23 2 

12 1 

10 2 

26 2 

5 0 

14 1 

19 1 

31 0 

30 0 

8 0 

4 1 

24 0 

11 0 

22 1 

25 0 

9 0 

27 0 

2 0 

18 0 

21 0 

2 

3 

2 

2 

2 

2 

3 

1 

1 

2 

0 

0 

0 

1 

0 

0 

1 

0 

0 

0 

0 

0 

0 

Ordered rabbit No.” 

3 

3 

2 

2 

2 

2 

3 

1 

1 

2 

0 

0 

I 

1 

1 

0 

1 

0 

0 

0 

0 

0 

0 

4 

8 

5 

3 

2 

3 

3 

2 

1 

2 

0 

1 

1 

1 

1 

0 

1 

1 

0 

0 

0 

0 

0 

5 

9 

5 

3 

4 

4 

4 

3 

3 

2 

2 

1 

2 

2 

2 

1 

1 

1 

0 

0 

0 

0 

0 

6 7 8 

No. Primary 

with irritation 

necrosis score 

22 30 -0 2b 5.5 

5 18 19 2 3.6 

3 3 15 1 2.1 

4 7 10 0 2.0 

6 6 6 0 1.9 

4 5 6 0 1.9 

3 4 5 0 1.2 

3 4 5 0 1.2 

3 3 4 0 1.2 

4 4 6 0 1.0 

1 2 9 1 0.9 

2 3 4 0 0.8 

2 2 3 0 0.8 

2 3 3 0 0.8 

3 3 5 0 0.8 

1 2 3 0 0.7 

1 1 3 0 0.4 

1 2 2 0 0.3 

0 2 2 0 0.2 

0 0 0 0 0.0 

0 0 0 0 0.0 

0 0 0 0 0.0 

a Rabbits ordered by degree of severity. 

b One rabbit died. 

The PI scores, with necrosis included, for each laboratory for each pertinent material 

are presented in Table 41, and those without necrosis in Table 42. The 8 laboratories 

which never recorded necrosis scores were 4, 5, 8, 9, 21, 24, 26, and 27. The maximum 

possible PI score, including necrosis, is 24; that without necrosis would be 8. While 

laboratory 21 recorded a PI of 0, laboratory 12 had a PI of 22.6, both for material L. 

Eleven laboratories had PI scores (Table 41) less than 5 for material F while 8 of the 22 

had scores higher than 10. Even for the nonnecrosis totals (erythema and edema only) 

(Table 42), laboratory 18 had a score of 0.5 versus 6.4 for laboratory 23 for F; 4 laboratories rated L at 2.0 or lower zwsus 3 at 7.2 or higher (out of a maximum PI score of 8). 

Note that, with material L, all of the 14 laboratories that read necrosis on any sample 
INTERLABORATORY EYE AND SKIN COMPARISONS 311 

recorded necrosis with this; but no necrosis was recorded in the other 8 laboratories 

even with this sample. Ten of the 14 reporting necrosis saw it on all of the 8 rabbits 

examined (Table 33). Six of the laboratories reported necrosis on half or more of the 

samples, making the practically completely and unexplainable negative results (no 

erythema, edema, or necrosis) of laboratory 21 even more remarkable. 

TABLE 31 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND PRIMARY 

IRRITATION SCORES WITH ETHOXYLATED LAURYL ALCOHOL (MATERIAL J) 

Ordered rabbit No.” 

Laboratory __-____ 

No. - 1 2 3 4 5 6 7 8 

No. 

with 

Primary 

irritation 

necrosis score 

25 5 6 17 19 19 20 22 23 6 8.2 

23 6 IO 13 14 16 19 20 25 6 7.7 

14 1 4 6 20 20 21 21 22 5 7.2 

13 5 9 9 9 17 18 28 -b 3b 6.8 

11 6 7 8 8 9 11 12 25 1 5.4 

9 7 9 9 10 11 12 13 13 0 5.2 

22 4 4 9 9 10 13 14 15 6 4.9 

31 1 2 5 5 5 7 10 11 0 4.3 

31 4 6 7 9 14 15 15 22 7 4.3 

7 0 1 2 2 4 19 19 21 3 4.2 

12 5 6 7 8 9 9 10 13 0 4.2 

10 4 5 6 7 7 7 9 12 1 3.6 

5 5 5 5 5 6 7 7 9 0 3.1 

8 4 5 5 6 6 7 7 7 0 2.9 

24 4 5 5 6 6 6 7 8 0 2.9 

30 3 3 4 5 6 7 7 7 0 2.6 

4 2 3 3 4 4 5 8 10 0 2.4 

2 3 3 4 4 4 4 5 7 0 2.1 

19 2 3 4 4 4 5 5 6 0 2.1 

27 0 2 2 2 4 6 6 9 0 1.9 

18 0 1 2 2 2 3 3 5 0 1.1 

26 1 1 1 1 2 2 2 3 0 0.8 

21 0 0 0 0 0 0 0 0 0 0.0 

’ Rabbits ordered by degree of severity. 

* One rabbit died. 

The ranks and sum of ranks, with and without the necrosis component, are presented 

in Tables 43 and 44, with the significant and near-significant sums presented in Table 45. 

With or without necrosis, laboratories 11, 12, and 14 reported consistently low sums 

(severe reactions) and laboratories 18 and 21 had high sums (low PI scores). Other 

laboratories with high sums of ranks were 27 and 30 on the with-necrosis basis, and 22 

with necrosis excluded. It is notable that while all of those with high sums recorded 

necrosis on some or all of the samples, 3 of the 5 with low sums also recognized, and 

scored, necrosis on 2 to 4 of the samples. 

The collaborative testing procedure clearly indicated that some laboratories consistently rated materials more irritating while other laboratories just as consistently rated 

the same materials less irritating than the ma,jority of the participating laboratories. 
312 WEIL AND SCALA 

The interlaboratory relative sums of ranks of PI, with and without necrosis, are presented in Table 46. The coefficient of rank correlation was higher than +0.85, a 

statistically significant figure. The laboratories that ranked 1, 2, 3, and 4 with necrosis 

scores ranked 1,3,2, and 4 without necrosis; those which ranked 19.5, 19.5,21, and 22 

with necrosis ranked 21, 19, 18, and 22, respectively, without scores for necrosis. Thus, 

even though some laboratories did not score necrosis on any spot for any material, while 

at least 1 score of necrosis was seen for 8 of the 10 samples, those which tended to have 

high PI scores with necrosis also rated relatively high when scores for necrosis (when 

present) were subtracted. 

TABLE 32 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND PRIMARY 

IRRITATION SCORES WITH DECAETHOXY OLEYL ETHER (MATERIAL K) 

- 

Laboratory - 

No. I 

23 24 

31 6 

13 11 

22 9 

14 11 

9 9 

12 7 

26 7 

10 6 

11 6 

7 1 

5 5 

4 4 

2 4 

25 4 

24 4 

19 4 

30 4 

8 4 

18 2 

27 0 

21 0 

2 3 4 5 6 7 

25 25 25 25 26 27 

16 28 29 29 29 32 

12 19 21 21 22 23 

10 10 14 15 15 25 

12 12 12 13 14 16 

9 10 11 11 12 12 

9 10 10 10 11 12 

7 8 8 8 9 9 

6 6 7 8 9 10 

6 8 8 8 9 9 

2 3 5 5 5 19 

6 7 7 8 8 8 

5 6 6 7 8 9 

5 6 6 7 8 8 

4 5 5 6 7 8 

4 5 5 6 6 7 

4 4 5 5 6 7 

4 4 4 5 5 6 

4 4 4 5 6 6 

2 2 3 3 5 9 

1 2 3 5 6 7 

0 0 0 0 0 0 

Ordered rabbit No.” No. Primary 

with irritation 

8 necrosis score 

27 8 12.8 

32 7 12.6 

-b 5b 9.2 

25 8 1.7 

16 8 6.6 

12 0 5.4 

14 0 5.2 

11 0 4.2 

13 0 4.1 

11 0 4.1 

20 2 3.8 

9 0 3.6 

9 0 3.4 

8 0 3.2 

9 0 3.0 

7 0 2.8 

8 0 2.7 

8 0 2.5 

6 0 2.4 

9 2 2.2 

8 0 2.0 

0 0 0.0 

’ Rabbits ordered by degree of severity. 

b One rabbit died. 

Certain unexplained anomalies occurred which kept some laboratories from having 

outlying sums of ranks. Samples M, N, 0, and P were sent to the laboratories several 

months later than the first 12 materials. Therefore, in most laboratories which had completed the first 12, they were tested later. Laboratory 13 had relative ranks of no higher 

than 4 in samples A to L, while it ranked 12 to 19.5 on M, N, and 0 (Tables 43 and 47) 

resulting in a sum of ranks of 69.5 (95 “/, lower limit is 55.1). Laboratory 3 1 had ranks of 

no higher than 10 for the first 12 samples, but ranks of 19 and 19.5 on N and 0. For the 
INTERLABORATORY EYE AND SKIN COMPARISONS 313 

first batch of 12 samples, by way of contrast, laboratory 18 had 6 ranks of 20 or higher, 

but ranked 7.5 to 11.5 for M, N, and 0. These differences may have resulted from 

changes in technicians, in stock of rabbits, in the season of the year, etc. 

TABLE 33 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND PRIMARY 

IRRITATION SCORES WITH LINOLEIC DIETHANOLAMIDE (MATERIAL L) 

Laboratory 

Ordered rabbit number” No. Primary 

--.-___ ___- with irritation 

No. 1 2 3 4 5 6 7 8 necrosis score 

12 41 45 45 46 46 46 46 46 8 22.6 

25 30 35 39 40 41 41 41 42 8 19.3 

13 22 27 29 30 36 36 36 -b 7b 15.4 

10 20 22 25 26 29 37 41 42 8 15.1 

22 25 25 29 30 30 30 31 32 8 14.5 

31 29 29 29 29 29 29 29 29 8 14.5 

11 12 12 13 33 34 34 44 46 5 14.2 

23 14 28 28 29 30 30 30 31 7 13.8 

14 17 18 20 20 21 21 25 28 8 10.6 

2 17 17 18 18 19 19 21 21 8 9.4 

19 10 14 17 18 18 19 26 -= 7’ 8.7 

9 15 16 16 16 16 16 16 16 0 7.9 

18 9 14 14 15 15 16 16 19 8 7.4 

4 IO II 12 13 13 13 13 13 0 6.1 

5 9 10 10 11 11 11 12 12 0 5.4 

27 8 8 9 10 11 11 11 12 0 5.0 

7 1 1 2 6 13 14 20 21 4 4.9 

24 8 9 9 10 10 10 10 11 0 4.8 

30 6 6 6 7 9 10 13 13 2 4.4 

26 6 7 7 8 9 9 11 11 0 4.2 

8 3 3 7 8 8 9 10 11 0 3.7 

21 0 0 0 0 0 0 0 0 0 0.0 

’ Rabbits ordered by degree of severity of reaction. 

’ One rabbit died. 

’ One rabbit injured in fight; skin not read. 

The statistical parameters associated with the PI scores, including the necrosis component when present, are summarized in Table 47 and Fig. 2. The laboratories are 

listed in order of lowest to highest sum of ranks, i.e. in order of those that read the highest 

(most severe) to those with the lowest (least severe) reactions. The 25th and 75th percentiles (Qi and Q& the measures of variability (the range and the SIQR), as well as the 

median ranks are included in Table 47. As for the eye test, the SIQR was quite high for 

some laboratories and low for others. The median SIQR for the skin was 3.5. Laboratory 21 had the lowest SIQR for the skin (0.7) as well as the highest SIQR for the eye test 

(9.2). The 2 laboratories with the highest skin SIQRs (laboratories 13 and 22), with 

ranks of 1.5 for the skin, ranked 12.5 and 20 of 21 laboratories for the eye tests. These 

comparative SIQRs and their ranks are presented in Table 48. The coefficient of rank 

correlation between the eye and skin SIQR was nearly zero ($0.00033). Therefore, there 
314 WEIL AND SCALA 

was no relationship in relative variability in rank between the laboratories on the eye 

and on the skin tests. 

Ordinarily, a low SIQR is more desirable than a high one. It indicates that, for the 

samples tested, the laboratory consistently had low variability around its median rank; 

from its 25th to 75th percentiles (Q1 and QJ. However, while this is true for laboratory 

21, with a median rank of 21.8 and with a Q, and Qj of 20.6 and 22.0, this laboratory 

attained these consistently high ranks by scoring a zero PI reaction for almost every 

rabbit. By contrast, the laboratory with the next smallest skin SIQR, laboratory 24, had 

PI scores ranging from 0.8 to 4.8. 

TABLE 34 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND PRIMARY 

IRRITATION SCORES WITH n-BIJTYL ALCOHOL (MATERIAL M) 

Laboratory - 

No. 1 

- -____- 

12 12 

II 8 

14 3 

10 2 

25 2 

31 0 

31 0 

2 0 

26 3 

23 0 

18 0 

5 3 

4 1 

24 0 

19 I 

9 0 

27 0 

8 0 

7 0 

13 0 

21 0 

30 0 

22 0 

2 

- 

12 

8 

4 

3 

3 

0 

12 

0 

4 

I 

1 

3 

2 

1 

1 

0 

0 

0 

0 

0 

0 

0 

0 

~- 

3 

- 

5 

13 14 15 

9 10 I1 

8 10 13 

3 3 5 

4 5 8 

0 0 0 

16 22 24 

0 1 1 

6 6 7 

2 2 2 

2 2 2 

4 4 4 

2 3 4 

2 3 3 

I 2 2 

0 0 I 

0 1 2 

0 1 1 

0 1 I 

0 0 0 

0 0 0 

0 0 1 

0 0 0 

Ordered rabbit No.” 

6 

- 

22 

21 

14 

25 

17 

0 

24 

I 

8 

3 

2.5 

4 

4 

3 

3 

I 

3 

2 

2 

0 

0 

1 

1 

- 

7 8 

46 46 

21 29 

14 46 

26 34 

25 35 

0 0 

31 32 

25 25 

9 10 

3 24 

6 18 

5 5 

4 4 

3 4 

3 4 

3 12 

3 4 

2 4 

2 2 

2 4 

0 6 

1 2 

1 1 

No. Primary 

with irritation 

necrosis score 

.~__ ~_ ~~~-~ - 

3 11.2 

3 7.3 

4 7.0 

3 6.3 

3 6.2 

0 5.0 

7 5.0 

2 3.3 

0 3.3 

I 2.3 

1 2.1 

0 2.0 

0 1.5 

0 1.2 

0 1.1 

0 1.1 

0 0.8 

0 0.6 

0 0.5 

0 0.4 

0 0.4 

0 0.3 

0 0.2 

e Rabbits ordered by degree of severity of reaction. 

The coefficient of rank correlation between the sum of ranks of PI and the SIQR 

(Table 47) was not significant, +0.401. Nevertheless, the correlation coefficient between 

rank of sum of ranks of the laboratories for relative skin irritation, the PI, and the rank 

of the sum of ranks of the laboratories for range of scores for individual rabbits (presented in Table 39) was +0.847, a very significant correlation. Thus, the laboratories that 

tended to have the highest PI also tended to have the smallest variation between readings 

on individual rabbits. 
INTERLABORATORY EYE AND SKIN COMPARISONS 315 

TABLE 35 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND PRIMARY 

IRRITATION SCORES WITH METHYL ETHYL KETONE (MATERIAL N) 

Laboratory ~~ 

No. 1 2 3 4 5 6 7 

No. Primary 

with irritation 

8 necrosis score 

12 4 4 4 6 7 7 8 12 0 3.2 

14 4 5 5 5 6 6 8 10 0 3.1 

10 0 1 2 2 3 3 13 24 2 3.0 

26 2 2 4 4 4 4 6 9 0 2.2 

11 0 2 2 3 4 5 6 6 0 1.8 

25 0 2 2 2 2 4 5 6 0 1.4 

5 1 1 2 2 2 3 4 4 0 1.2 

24 0 1 1 2 2 2 2 3 0 0.8 

19 0 0 1 1 1 2 2 3 0 0.6 

7 0 0 1 1 1 2 2 2 0 0.6 

2 0 0 0 0 0 0 1 3 0 0.2 

18 0 0 0 0 0 0 0 3 0 0.2 

22 0 0 0 0 0 0 1 1 0 0.1 

23 0 0 0 0 0 0 1 1 0 0.1 

30 0 0 0 0 0 0 1 I 0 0.1 

4 0 0 0 0 0 0 0 1 0 0.1 

8 0 0 0 0 0 0 0 0 0 0.0 

9 0 0 0 0 0 0 0 0 0 0.0 

21 0 0 0 0 0 0 0 0 0 0.0 

27 0 0 0 0 0 0 0 0 0 0.0 

31 0 0 0 0 0 0 0 0 0 0.0 

13 0 0 0 0 0 0 0 0 0 0.0 

Ordered rabbit No.” 

’ Rabbits ordered by degree of severity of reaction. 

D. Intralaboratory Sample Ranks 

The previous sections included discussion of the results where the relative irritancy of 

pertinent samples tested was used to rank the laboratories. Another aspect of these tests 

is the manner in which the laboratories ranked the samples. In other words, relatively, 

do most laboratories rate low-irritating materials differently from those of a higher 

degree of irritancy ? Therefore, for each laboratory, the pertinent materials were ranked 

from 1 to N; the rank of 1 being assigned to the material with the highest irritation score, 

2 to that next most irritating, etc. The ranks were summed for each material and are 

presented for the eye tests in Tables 49,50, and 5 1 and for the skin tests in Tables 52 and 

53. Major differences did occur; e.g., laboratories 2 and 4 rated material G as the least 

irritating of the 9 materials on the eye while 16 laboratories rated G as the most 

irritating. 

The sums of ranks, and designations of deviation from the respective 95 % probability 

limits, are presented in Table 55. With only 9 materials for the eye test (or 8 if material G 

is not used in these tabulations) and with 10 for the skin test, less than 1 of these might be 

expected to be unusually high or low in relative rank if the laboratories did not consistently rate the materials high or low. This expectation was not borne out, however. 
316 WEIL AND SCALA 

Materials F, G, and L were rated consistently as more irritating to the eyes than the 

other materials while, in one or more of the various categories, reference or nonreference, materials A, K, N, and P were ranked as relatively nonirritating to the eyes 

(compared with the other materials tested). 

TABLE 36 

SKIN-REFERENCE METHOD-SCORES OF INDIVIDUAL RABBITS AND PRIMARY 

IRRITATION SCORES WITH METHYL ISOBUTYL KETONE (MATERIAL 0) 

Ordered rabbit No.” Primary 

No. 1 2 3 4 

9 

7 

4 

2 

3 

2 

2 

2 

2 

2 

2 

0 

1 

1 

1 

1 

0 

0 

0 

0 

0 

0 

0 

No. 

5 

with irritation 

6 7 8 necrosis score 

Laboratory __ 

12 6 9 9 

11 3 6 6 

14 2 2 4 

26 2 2 2 

24 1 2 3 

25 1 2 2 

9 0 1 2 

18 0 0 1 

5 1 1 2 

10 0 0 1 

30 1 1 1 

13 0 0 0 

23 0 0 1 

7 0 0 1 

27 0 0 0 

19 0 0 0 

8 0 0 0 

2 0 0 0 

31 0 0 0 

31 0 0 0 

22 0 0 0 

4 0 0 0 

21 0 0 0 

11 11 11 12 0 4.9 

7 8 8 9 0 3.4 

6 7 7 8 0 2.5 

4 5 5 7 0 1.8 

3 3 4 4 0 1.4 

2 3 4 5 0 1.3 

2 4 4 5 0 1.2 

2 2.5 5 7 0 1.2 

2 3 3 4 0 1.1 

3 3 4 5 0 1.1 

2 3 3 3 0 1.0 

0 2 3 9 1 0.9 

1 2 2 3 0 0.6 

1 2 2 2 0 0.6 

1 2 2 3 0 0.6 

1 1 2 2 0 0.4 

1 1 1 2 0 0.3 

0 1 2 2 0 0.3 

0 0 0 0 0 0.2 

0 0 1 4 0 0.2 

0 0 1 1 0 0.1 

0 0 0 0 0 0.0 

0 0 0 0 0 0.0 

a Rabbits ordered by degree of severity of reaction. 

Similarly, F, L, and K were relatively irritating and G, I, N, and 0 relatively nonirritating in the skin test. Therefore, the laboratories, on the whole, ranked the 

materials much more consistently than might have been expected by chance, if the use 

of these methods did not allow a laboratory to show, by its own testing facilities, which 

material was relatively more irritating than the others. Much more agreement on the 

relative ranking of the samples by the laboratories was found than on the relative ranking of the laboratories by the samples (intra- as opposed to interlaboratory ranking). 

It is interesting that material G was the most irritating sample tested on the eye but the 

least irritating on the skin (Table 55). 

Comparisons (Table 54) were made between the correlation of the relative irritation 
TABLE 37 

MINIMUM-MAXIMUM SCORE FOR REFERENCE PROCEDURE SKIN TEST-INDIVIDUAL 

Laboratorv 

- No.” E 

Material 

F G I J K L M 

12 

14 

11 

13 

10 

25 

31 

23 

26 

5 

9 

2 

19 

24 

22 

7 

8 

4 

18 

30 

27 

21 

Any 

laboratory 

O-4 

3-10 

5-7 

2-19 

O-4 

2-9 

O-8 

O-4 

l-8 

5-7 

l-4 

4-9 

3-8 

1-4 

o-2 

2-5 

2-7 

&3 

o-l 

o-2 

O-1 

All 0 

O-19 

21-46 2-8 l-10 5-l 3 7-14 41-46 12-46 

5-22 2-7 l-5 l-22 11-16 17-28 3-46 

6-44 O-8 O-5 6-25 &I1 1246 8-29 

2046 2-l 6 2-30 5-28 11-23 22-36 e-4 

23-31 1-5 2-6 4-12 6-13 20-42 2-34 

4-44 o-3 o-3 5-23 4-9 30-42 2-35 

31-33 O-20 o-6 l-22 6-32 All 29 o-32 

7-30 O-3 2-15 6-25 24-27 14-31 O-24 

6-13 1-8 2-6 1-3 7-l 1 611 3-10 

6-11 o-4 O-l 5-9 5-9 9-12 3-5 

6-16 2-8 O-2 7-13 9-12 15-16 o-12 

21-38 o-1 All 0 3-7 4-8 17-21 O-25 

6-10 l-5 14 2-6 4-8 l&26 1-4 

5-9 o-2 o-3 4-8 4-7 8-11 @4 

8-32 o-2 l-3 4-15 9-25 25-32 O-l 

2-6 All 0 2-19 o-21 l-20 1-21 o-2 

2-l 3 o-3 o-4 4-7 4-6 3-11 O-4 

3-6 o-1 l-3 2-10 4-9 lo-13 l-4 

&6 All 0 All 0 O-5 2-9 9-19 O-18 

l-5 Cl o-9 3-7 4-8 6-13 O-2 

5-12 O-l O-2 o-9 O-8 8-12 O-4 

All 0 All 0 All 0 All 0 All 0 All 0 O-6 

O-46 O-20 O-30 O-28 O-32 046 O-46 

’ Laboratories ordered by sum of ranks for primary irritation as in Table 47. 
318 WEIL AND SCALA 

rank of the materials in each laboratory and the overall interlaboratory rank of the 

same materials. For example, from Table 49 for laboratory 4: 

Material 

Rank in Overall rank in 

laboratory 4 all laboratories 

A 8 6 

F 3 2 

G 9 1 

J 5 5 

K 1 9 

L 6.5 3 

M 2 4 

N 6.5 7 

P 4 8 

TABLE 38 

RANGE OF SCORES FOR REFERENCE PROCEDURE SKIN TESTINDIVIDUAL RABBITS’ 

Laboratory - 

No.~ E 

Range for material 

F G I J K L M N 0 

12 4 25 6 9 8 7 5 34 8 6 

14 7 17 5 4 21 4 11 43 6 6 

11 2 38 8 4 19 5 34 21 6 6 

13 17 26 14 28 23 12 14 4 0 9 

10 4 8 4 4 8 7 22 32 24 5 

25 7 40 3 3 18 5 12 33 6 4 

31 8 2 17 6 21 26 0 32 0 4 

23 4 23 3 13 19 3 17 24 1 3 

26 7 7 7 4 2 4 5 7 7 5 

5 2 5 4 1 4 4 3 2 4 3 

9 3 10 6 2 6 3 1 12 0 5 

2 5 17 1 0 4 4 4 25 3 2 

19 5 4 4 3 4 4 16 3 3 2 

24 3 4 2 3 4 3 3 4 3 3 

22 2 24 2 2 11 16 7 1 1 1 

7 3 4 0 17 21 19 20 2 2 2 

8 5 11 3 4 3 2 8 4 0 2 

4 3 3 1 2 8 5 7 3 1 0 

18 1 6 0 0 5 7 12 18 3 7 

30 2 4 1 9 4 4 7 2 1 2 

27 1 7 1 2 9 8 4 4 0 3 

21 0 0 0 0 0 0 0 6 0 0 

n Range = maximum minus the minimum. 

b Laboratories ordered by sum of ranks for primary irritation as in Table 47. 
TABLE 39 

RANK AND SUM OF RANKS OF RANGES LISTED IN TABLE 38 

Rank of range for material 

Laboratory 

No.“ 

12 

14 

11 

13 

10 

25 

31 

23 

26 

5 

9 

2 

19 

24 

22 

7 

8 

4 

18 

30 

27 

21 

E F 

_-~ .~~ .~__ 

10 4 

4 7.5 

17.5 2 

1 3 

10 11 

4 1 

2 21 

10 6 

4 12.5 

17.5 15 

13.5 10 

7 7.5 

7 17.5 

13.5 17.5 

17.5 5 

13.5 17.5 

7 9 

13.5 20 

20.5 14 

17.5 17.5 

20.5 12.5 

22 22 

G I 

.--__ -... 

J 

5.5 4.5 11 

7 9 3 

3 9 5.5 

2 1 1 

9 9 11 

12 13 7 

1 6 3 

12 3 5.5 

4 9 21 

9 19 17 

5.5 16.5 13 

17.5 21 17 

9 13 17 

14.5 13 17 

14.5 16.5 8 

21 2 3 

12 9 20 

17.5 16.5 11 

21 21 14 

17.5 4.5 17 

17.5 16.5 9 

21 21 22 

K 

7 

14.5 

10 

4 

7 

10 

1 

19 

14.5 

14.5 

19 

14.5 

14.5 

19 

3 

2 

21 

10 

7 

14.5 

5 

22 

L M 

- 

14.5 2 

9 1 

1 8 

6 14.5 

2 4.5 

7.5 3 

21.5 4.5 

4 7 

14.5 11 

18.5 20 

20 10 

16.5 6 

5 17.5 

18.5 14.5 

12 22 

3 20 

10 14.5 

12 17.5 

7.5 9 

12 20 

16.5 14.5 

21.5 12 

a Laboratories ordered by sum of ranks for primary irritation as in Table 47. 

d Outside limits; CG,.~~ = 55.1 to 174.9. 
TABLE 40 

ERYTHEMA, EDEMA, AND NECROSIS COMPONENTS OF TOTAL SCORE FOR MATERIALS F AND K-REFE

Material F 

Total score of 8 rabbits for Total score of 8 

Erythema 

Laboratory ____ --- 

No.” 24Hr 72 Hr 

__~~~ ~___ 

12 28 30 

14 22 20 

11 19 20 

13 16 21b 

10 15 17 

25 17 21 

31 28 SC 

23 30 30 

26 25 16 

5 13 20 

9 28 32 

2 19 28 

19 14 12 

24 17 19 

22 16 18 

7 9 16 

8 23 20 

4 13 16 

18 1 3 

30 7 12 

27 13 22 

21 0 0 

Edema Necrosis 

24 Hr 72 Hr 24 Hr 

~.__ 

85 

0 

40 

20 

40 

60 

80 

0 

0 

E! 

65 

0 

0 

25 

0 

0 

0 

0 

0 

0 

0 

72 Hr 

25 

13 

26 

14 

17 

18 

26 

15 

21 

9 

23 

15 

15 

14 

10 

0 

15 

4 

1 

0 

8 

0 

__ 

28 

10 

22 

27b 

15 

23 

SC 

27 

17 

18 

28 

0 

20 

13 

3 

8 

16 

4 

3 

6 

21 

0 

Primary Erythema Edem

- 

irritation 

score 24 Hr 

100 

50 

40 

95h 

110 

80 

120 

75 

0 

E”o 

110 

0 

0 

75 

0 

0 

0 

0 

0 

0 

0 

18.5 24 

7.2 23 

10.4 19 

14.2 19 

13.4 16 

13.7 8 

15.9 29 

11.1 24 

4.9 22 

3.8 14 

6.9 19 

14.8 16 

3.8 11 

3.9 14 

9.8 16 

2.1 15 

4.6 14 

2.3 16 

0.5 5 

1.6 12 

4.0 4 

0.0 0 

72 Hr 24Hr 

~ ____. 

23 

22 

23 

26” 

20 

22 

s” 

32 

24 

15 

27 

15 

12 

24 

22 

15 

15 

19 

13 

20 

14 

0 

16 

10 

8 

17 

14 

1 

6 

6 

16 

9 

10 

6 

5 

0 

0 

0 

I 

5 

2 

1 

0 

0 

’ Laboratories ordered by sum of ranks for primary irritation as in Table 47. 

b Score is for 7 rabbits as one died or was injured in a fight. 

c “Large scab obscured any possible reading of erythema or edema at 72 hr.” 

d “Superficial eschar which healed without scar.” 
INTERLABORATORY EYE AND SKIN COMPARISONS 321 

TABLE 41 

SKIN-SCORE OF REFERENCE METHOD (WITH NECROSIS SCORE) 

Laboratory 

No. E F 

__ 

G 

2 3.8 14.8 0.2 

4 0.7 2.3 0.1 

5 2.8 3.8 1.1 

7 1.8 2.1 0.0 

8 1.9 4.6 0.8 

9 1.5 6.9 2.6 

10 0.9 13.4 1.4 

11 3.1 10.4 1.2 

12 1.1 18.5 2.1 

13 5.2 14.2 3.3 

14 2.9 7.2 1.9 

18 0.1 0.5 0.0 

19 2.6 3.8 1.1 

21 0.0 0.0 0.0 

22 0.4 9.8 0.4 

23 0.4 11.1 0.4 

24 1.2 3.9 0.5 

25 2.1 13.7 0.6 

26 1.2 4.9 2.5 

27 0.1 4.0 0.1 

30 0.4 1.6 0.1 

31 1.9 15.9 4.1 

- 

Material 

1 J 

0.0 2.1 

0.8 2.4 

1.2 3.1 

3.6 4.2 

0.8 2.9 

0.3 5.2 

1.9 3.6 

0.8 5.4 

2.0 4.2 

5.5 6.8 

1.2 7.2 

0.0 1.1 

1.2 2.1 

0.0 0.0 

0.7 4.9 

2.1 7.7 

0.8 2.9 

0.4 8.2 

1.9 0.8 

0.2 1.9 

0.9 2.6 

1.0 4.6 

K L M N 0 

3.2 9.4 3.3 0.2 0.3 

3.4 6.1 1.5 0.1 0.0 

3.6 5.4 2.0 1.2 1.1 

3.8 4.9 0.5 0.6 0.6 

2.4 3.7 0.6 0.0 0.3 

5.4 7.9 1.1 0.0 1.2 

4.1 15.1 6.3 3.0 1.1 

4.1 14.2 7.3 1.8 3.4 

5.2 22.6 11.2 3.2 4.9 

9.2 15.1 0.4 0.0 0.9 

6.6 10.6 7.0 3.1 2.5 

2.2 7.4 2.1 0.2 1.2 

2.7 8.7 1.1 0.6 0.4 

0.0 0.0 0.4 0.0 0.0 

7.7 14.5 0.2 0.1 0.1 

12.8 13.8 2.3 0.1 0.6 

2.8 4.8 1.2 0.8 0.4 

3.0 19.3 6.2 1.4 1.3 

4.2 4.2 3.3 2.2 1.8 

2.0 5.0 0.8 0.0 0.6 

2.5 4.4 0.3 0.1 1.0 

12.6 14.5 5.1 0.0 0.2 

The rank correlation coefficient for the preceding text table (page 318) is -0.379. The 

significance notation in Table 54 is the opposite of that in the other tables in this presentation. Instead of denoting the laboratories that significantly correlated well with 

the overall intralaboratory ranking of the samples, the laboratories that lacked 

significant correlation are delineated. Considerable differences were seen, in some 

laboratories, depending on whether material G was or was not excluded on the reference 

eye test. For example, laboratories 2 and 31 lacked significant correlation when G was 

included, but correlated very well without G. While many laboratories on the eye test 

lacked significant correlation of relative sample irritation with overall irritation ranking; 

fewer did on the skin test. It is notable that, without G, laboratories 14 and 31 had good 

correlation using the reference eye procedure but lacked significant correlation using 

their nonreference eye tests. Similarly, laboratory 31 correlated well on the reference 

but not on the nonreference skin test. The intercorrelations of reference with nonreference tests within each laboratory will be further discussed later. For laboratory 3 1, 

however, their nonreference eye and skin tests were considerably different from the 

reference procedures. Different volumes were used on the eyes in the nonreference 

procedures, irritation was recorded after uncovered application on the skin, and 

different grading systems were used for both tests. 
TABLE 42 

SKIN-SCORE OF REFERENCE METHOD(WITHOUT SCORE FOR NECROSIS

Laboratory 

No. E F G 

13 3.4” 6.0” 2.2” 

31 1.9 3.4” 1.9” 

10 0.9 4.0” 1.4 

14 2.9 4.1” 1.9 

23 0.4 6.4” 0.4 

25 1.8” 4.9” 0.6 

7 1.8 2.1 0.0 

11 3.1 5.4” 1.2 

22 0.4 2.9“ 0.4 

2 3.8 3.9” 0.2 

12 1.1 6.9” 2.1 

18 0.1 0.5 0.0 

19 2.6 3.8 0.8” 

30 0.4 1.6 0.1 

4 0.7 2.3 0.1 

5 2.8 3.8 1.1 

8 1.9 4.6 0.8 

9 1.5 6.9 2.6 

24 1.2 3.9 0.5 

26 1.2 4.9 2.5 

27 0.1 4.0 0.1 

21 0.0 0.0 0.0 

Material 

~~~ ___~~ ~~ __ 

I J K L M 

3.7” 4.6” 5.6” 7.2” 

1.0 2.6” 2.6” 2.0” 

1.9 2.9” 4.1 4.8” 

1.2 4.1” 3.8” 5.0” 

2.1 4.7” 5.2’ 7.2” 

0.4 2.9” 3.0 4.9” 

1.8” 1.4” 1.9” 1.8” 

0.8 4.4” 4.1 6.8” 

0.7 2.1” 2.4” 2.6” 

0.0 2.1 3.2 1.9” 

2.0 4.2 5.2 7.9” 

0.0 1.1 1.6” 2.4” 

1.2 2.1 2.7 4.1” 

0.6“ 2.6 2.5 3.8” 

Laboratories that scored no necrosis 

0.8 2.4 3.4 6.1 1.5 

1.2 3.1 3.6 5.4 2.0 

0.8 2.9 2.4 3.7 0.6 

0.3 5.2 5.4 7.9 1.1 

0.8 2.9 2.8 4.8 1.2 

1.9 0.8 4.2 4.2 3.3 

0.2 1.9 2.0 5.0 0.8 

0.0 0.0 0.0 0.0 0.4 

0.4 

0.5” 

1.9” 

4.2” 

1.1” 

2.8“ 

0.5 

4.8” 

0.2 

0.9” 

6.9” 

1.2” 

1.1 

0.3 

a Necrosis had been scored on this sample in this laboratory. 
TABLE 43 

SKIN-RANKS AND SUMSOF RANKS OF PRIMARYIRRITATION SCORES(WITH NECR

Laboratory 

Material 

No. E F G I J K L M 

2 2 3 16 21 17.5 14 10 7.5 

4 16 18 18 13.5 16 13 14 12 

5 5 16.5 9.5 8 12 12 15 11 

7 10 19 21 2 9.5 11 17 18 

8 8.5 13 11 13.5 13.5 19 21 17 

9 11 11 3 18 6 6 12 14.5 

10 15 6 7 5.5 11 9.5 3.5 4 

11 3 8 8 13.5 5 9.5 7 2 

12 14 1 5 4 9.5 7 1 1 

13 1 4 2 1 4 3 3.5 19.5 

14 4 10 6 8 3 5 9 3 

18 20.5 21 21 21 20 20 13 10 

19 6 16.5 9.5 8 17.5 17 11 14.5 

21 22 22 21 21 22 22 22 19.5 

22 18 9 14.5 16 7 4 5.5 22 

23 18 7 14.5 3 2 1 8 9 

24 12.5 15 13 13.5 13.5 16 18 13 

25 7 5 12 17 1 15 2 5 

26 12.5 12 4 5.5 21 8 20 7.5 

27 20.5 14 18 19 19 21 16 16 

30 18 20 18 11 15 18 19 21 

31 8.5 2 1 10 8 2 5.5 6 

a Outside limits; CQ.,,~ = 55.1 to 174.9. 
TABLE 44 

SKIN-RANKS AND SUMS OF RANKS OF PRIMARY IRRITATION SCORES (WITHOUT SCOR

Laboratory 

No. 

13 2 4 3 1 3 1 

31 7.5 16 5.5 10 12.5 15 

10 15 10.5 7 4.5 9.5 6.5 

14 4 9 5.5 8 6 8 

23 18 3 14.5 2 2 3.5 

25 9.5 6.5 12 17 9.5 12 

7 9.5 19 21 6 19 20 

11 3 5 8 12.5 4 6.5 

22 18 17 14.5 15 16 17.5 

2 1 12.5 16 21 16 11 

12 14 1.5 4 3 5 3.5 

18 20.5 21 21 21 20 21 

19 6 14.5 10.5 8 16 14 

30 18 20 18 16 12.5 16 

E F G I 

-__ 

4 16 18 

5 5 14.5 

8 7.5 8 

9 11 1.5 

24 12.5 12.5 

26 12.5 6.5 

27 20.5 10.5 

21 22 22 

Material 

J K 

10 5 

21 17.5 

5 2 

17 19.5 

20 14 

1.5 1 

18 9.5 

14 12 

L M N 

3.5 19.5 19.5 

19 17.5 19.5 

11.5 7 7 

8.5 3 2 

3.5 12 14.5 

5 

9.5 

4 

14.5 

11.5 

1 

11.5 

9.5 

15 22 14.5 

Laboratories that scored no necrosis 

18 12.5 14 10 6 8 14.5 

9 8 7 9 7 6 6 

10.5 12.5 9.5 17.5 16 16 19.5 

1 18 1 2 1.5 12 19.5 

13 12.5 9.5 13 11.5 9.5 8 

2 4.5 21 5 13 4 3 

18 19 18 19 8.5 15 19.5 

21 21 22 22 22 21 19.5 

u Outside limits; q,,05 = 55.1 to 174.9. 
INTERLABORATORY EYE AND SKIN COMPARISONS 325 

TABLE 45 

SIGNIFICANT AND NEAR-SIGNIFICANT SUMS OF RANKS FOR RANGE-SKIN REFERENCE TESTY 

Primary irritation scores 

Laboratory 

No. Range 

Including Excluding No. of samples 

necrosis component necrosis component with necrosis 

13 53.0b 8 

14 64.0 53.0b 57.0 5 

12 64.5 44.5” 35.5b 3 

11 65.0 63.0 52.0b 4 

22 169.0 4 

18 165.5 171.0 3 

30 165.5 2 

27 177.0b 0 

21 204.5b 212.5b 214.0b 0 

’ Near-significant = within 10 points of pertinent 95 % limits listed. 

b q.05 limits = 55.1 to 174.9. 

TABLE 46 

COMPARISON OF RANKS WITH AND WITHOUT NECROSIS-REFERENCE SKIN TEST 

Laboratory No. of Sum of ranks ~ 

Relative rank of lab 

No. and samples with With Without With Without 

type”qb necrosis necrosis necrosis necrosis necrosis 

.._~~ .~ 

12T 

14c 

111 

13T 

1oc 

251 

311 

23T 

26G 

5c 

91 

2G 

19c 

24T 

22c 

71 

8T 

4c 

18C 

3oc 

271 

21G 

3 44.5’ 35.5’ 1 1 

5 53.0” 57.0 2 3 

4 63.0 52.0” 3 7 

8 69.5 70.0 4 i 

5 74.0 88.0 5 9 

5 76.0 92.5 6 10 

6 81.5 141.5 7 16 

5 91.0 86.5 8 8 

0 98.5 75.5 9 6 

0 105.5 81.0 10 7 

0 108.5 75.0 11 5 

3 120.0 140.5 12 15 

2 125.5 120.5 13 12 

0 127.5 107.0 14 11 

4 130.5 169.0 15 20 

4 131.0 156.0 16 17 

0 153.5 134.5 17 13 

0 156.5 138.5 18 14 

3 165.5 171.0 19.5 21 

2 165.5 163.0 19.5 19 

0 177.0” 161.5 21 18 

0 212.5” 214.0’ 22 22 

Coefficient of 

rank correlation - 

Concordance 

0.882 0.855 

4.67 5.24 - 

’ Laboratories ordered by sum of ranks for primary irritation as in Table 47. 

b See Table 1. 

c Outside limits; ~~~~~ = 55.1 to 174.9. 
TABLE 47 

SKIN REFERENCE METHOD PARAMETERS 

Laboratory Sum 

No. and of 

type” rank? 

Q2 

Median 

rank Ql Q3 

12T 

14c 

111 

13T 

44.5’ 2.5 1.0 7.6 

53.0” 4.5 3.0 8.2 

63.0 6.0 2.8 8.4 

69.5 3.8 1.8 13.9 

Semiinterquartile 

range, SIQR Range 

3.3 1 to 14 

2.6 2to 10 

2.8 2 to 13.5 

6.0 1 to 19.5 

1oc 74.0 6.5 3.4 9.9 3.2 3 to 15 

251 76.0 6.0 4.2 12.8 4.3 1 to17 

311 81.5 7.0 2.0 12.2 5.1 1 to 19.5 

23T 91.0 8.5 2.8 14.5 

26G 98.5 7.8 4.0 14.4 

5c 105.5 10.2 7.8 12.8 

91 108.5 11.0 6.0 15.4 

2G 120.0 12.2 6.4 17.5 

19c 125.5 12.8 9.1 16.6 

24T 127.5 13.2 11.4 15.2 

22c 130.5 14.5 6.6 18.5 

71 131.0 12.5 9.5 18.8 

8T 153.5 15.2 13.5 19.1 

4c 156.5 15.2 13.4 18.0 

18C 165.5 20.0 11.1 21.0 

3oc 165.5 18.0 13.6 19.2 

271 177.0” 18.5 15.5 19.8 

21G 212.5” 21.8 20.6 22.0 

5.8 1 to 18 

5.2 4 to 21 

2.5 5 to 16.5 

4.7 3 to 19.5 

5.6 2 to 21 

3.8 6 to 17.5 

1.9 5 to 18 

6.0 4 to 22 

4.6 2 to 21 

2.8 8.5 to 21 

2.3 12 to 21.5 

5.0 7.5 to 21 

2.8 11 to 21 

2.2 14to21 

0.7 19.5 to 22 

Un

5 of 10 ran

7 of 10 ra

outside

8 of 10 ran

outside

6 of 8 rank

10 of 12--

’ See Table 1. 

b Based on primary irritation scores with necrosis. 

‘Outside limits; aa.os =55.1 to 174.9. 
INTERLABORATORY EYE AND SKIN COMPARISONS 327 

i-T--1--~ T-T--I I I I I I I I I 1 

FIRST QUARTILE 

Q2 SECOND QUARTILE 

THIRD QUARTILE 

I 

SKIN 

lc---------ao o5 FiD”ClAL LlMITS - 

I I I I I I I I I III I I I I I I I 

30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 

SUM OF RANKS 

FIG. 2. Sum of ranks, median, and variability-Skin reference procedure. 

TABLE 48 

COMPARISON OF SEMI-INTERQUARTILE RANGE (SIQR) 

OF REFERENCE EYE AND SKIN TESTS 

SIQR Rank of SIQR 

Laboratory Eye Skin Eye Skin 

No. test test test test 

21 9.2 0.7 1 21 

7 7.2 4.6 2 8 

2 6.2 5.6 3 4 

25 5.5 4.3 4 9 

8 5.2 2.8 5 14 

10 4.9 3.2 6 12 

19 4.8 3.8 7 10 

11 3.9 2.8 8 14 

5 3.8 2.5 9.5 17 

23 3.8 5.8 9.5 3 

18 3.6 5.0 11 6 

13 3.4 6.0 12.5 1.5 

24 3.4 1.9 12.5 20 

31 3.1 5.1 14 5 

27 3.0 2.2 15 19 

30 2.8 2.8 16 14 

9 1.9 4.7 17 7 

12 1.5 3.3 18.5 11 

14 1.5 2.6 18.5 16 

22 1.4 6.0 20 1.5 

4 1.2 2.3 21 18 

Coefficient of rank correlation +0.00033 
328 WEIL AND SCALA 

Laboratories 21 and 26, both governmental laboratories, also lacked significant 

correlation on their nonreference skin procedures with the overall, all-laboratory, 

sample ranking by the reference procedure. The reference procedure results of laboratory 21 have been previously discussed in some detail. Laboratory 26, like laboratory 3 1, 

discussed above, used uncovered skin and a different scoring system while the nonreference procedure of laboratory 21 was quite similar to the reference test. 

TABLE 49 

EYE-INTRALABORATORY SAMPLE RANK-L%-HR MEDIAN-REFERENCE METHOD 

Laboratory --~ 

No. A 

-__ 

1 

2 

4 

5 

I 

8 

9 

10 

11 

12 

13 

14 

16 

18 

19 

21 

22 

23 

24 

25 

27 

29 

30 

31 

2 3 1 6 8 5 7 9 4 

7 3 9 4 8 1 2 5 6 

8 3 9 5 1 6.5 2 6.5 4 

9 3 1.5 1.5 6.5 6.5 6.5 6.5 4 

3 2 1 5 4 6 7.5 7.5 9 

9 5.5 1 2 8 7 4 5.5 3 

5.5 5.5 1 2.5 8 4 2.5 7 9 

8 4 2 6 9 1 3 5 7 

8 7 1 5 9 2.5 2.5 4 6 

7.5 5 1 6 9 2 3 7.5 4 

2 6 1 9 7.5 7.5 4 4 4 

7 I 6 3.5 9 3.5 2 5 8 

2.5 6 1 5 4 2.5 7 9 8 

2 3.5 1 6 8 7 3.5 9 5 

9 6 1 5 2.5 4 7 2.5 8 

6 2 3 1 5 4 7.5 7.5 9 

8 1 7 4 9 3 2 5.5 5.5 

7 4 1 2 8 3 5 9 6 

5.5 8 1 2 7 3.5 3.5 5.5 9 

2 5 1 6 9 3 4 8 7 

5 2.5 1 7 8 4 2.5 9 6 

3 2 1 5 6 4 7.5 7.5 9 

8 1.5 6 4.5 4.5 3 7 1.5 9 

5 4 6.5 6.5 8 2 1 3 9 

Sum of 

ranks 

F G J 

Material 

K 

139 93.5 65” 109.5 166” 

L 

___ 

95.5 

M N P 

- 

103.5 149.5 158.5 

a Outside limits; Q,.,J~ = 80.5 to 159.5. 

E. Nonreference versus Reference Procedures 

In the previous section, comparisons were made of differences in some laboratories 

between ranking the severity of irritation of the pertinent samples by the reference (R) 

or nonreference (NR) procedure and the overall rank of all laboratories of these 

materials by the reference procedure. In this section, comparisons will be made 

between R and NR in each laboratory where both procedures were run. These 
INTERLABORATORY EYE AND SKIN COMPARISONS 329 

correlations for each such laboratory are presented in Tables 56 and 57 for the eye and 

skin tests, respectively. As in Table 54, the nonsignificant correlations are delineated, 

i.e., those where the rank coefficients of correlation were not different from zero. 

TABLE 50 

EYE-INTRALABORATORY SAMPLE RANK-MEDIAN OF MEDIANSREFERENCE METHOD 

Laboratorv 

Material 

No. - A F G J K L M N P 

1 7 2 1 5 8 3 6 9 4 

2 6.5 1 8 2 5 3 4 6.5 9 

4 5 2 9 6 1 4 3 7 8 

5 9 8 4 2 1 3 5 6 7 

7 3 2 1 5 4 6 7 9 8 

8 9 3 1 2 6 4 5 7 8 

9 5 3 1 4 6 2 7 8 9 

10 7 5 4 3 8 1 2 6 9 

I1 7 5 1 2 8 3 4 6 9 

12 9 2 3 5 8 1 4 6 7 

13 7 2 1 6 9 8 3 4 5 

14 8 3 5 1 9 2 4 6 7 

16 5.5 4 1 5.5 2 3 7 9 8 

18 7 1 3 2 4.5 4.5 6 9 8 

19 9 4.5 1 4.5 3 2 7 6 8 

21 5 2 1 3 6.5 4 6.5 8 9 

22 9 1 7 3 8 6 2 5 4 

23 5 4 1 3 6 2 8 9 7 

24 2 5 1 3.5 3.5 7.5 6 7.5 9 

25 5 6 1 4 8 2 3 9 7 

27 4 3 1 9 6 2 5 8 7 

29 6 2 1 3 5 4 8 7 9 

30 8 3.5 6 1 2 5 7 3.5 9 

31 7 3 6 5 4 2 1 9 8 

Sum of 

ranks 155 77” 69" 89.5 131.5 84 120.5 170.5" 183" 

’ Outside limits; ~~~~~ = 80.5 to 159.5. 

The correlations were almost all significant on the eye and the skin procedures using 

12 samples, rather than the 9 or 10 pertinent ones used in all of the previous discussions. 

Thus, the inclusion of the data on materials E, I, and 0 for the eye and on A and P for 

the skin tests generally decreased discrimination between reference and nonreference 

procedures in the laboratories. The 2 and 1 nonsignificant correlations, using all 12 

materials for eye and skin comparisons, will not be further discussed, as most of the 

same laboratories still had nonsignificant correlations when the data for the lowdifferentiating materials were removed. 
330 WEIL AND SCALA 

TABLE 51 

EYE-INTRALABORATORY SAMPLE RANK-MEDIAN OF MEDIANS-NONREFERENCE METHOD 

Laboratory ____- 

No. 

-_ ._ 

1 

4 

5 

7 

8 

9 

10 

11 

13 

14 

16 

22 

24 

27 

30 

31” 

___- 

Sum of 

ranks 

- 

A F G J 

Material 

-____ 

K L M N P 

5.5 2 1 

6 2.5 9 

9 7 3 

8.5 1.5 8.5 

9 2 1 

5 3 1 

5 3 1 

9 1 7 

8 7 9 

8.5 2 5.5 

5 2 1 

8 4 5 

3 4 1 

8 3 1 

8 5 7 

5 1 7 

7 

4 

2 

3 

6.5 

4 

7 

3 

2 

5.5 

3 

3 

2 

4 

4 

6 

8 

1 

1 

1.5 

5 

7 

8 

8 

3 

8.5 

6 

2 

5 

6 

3 

8 

__. ~__ 

3.5 5.5 

7 2.5 

4 5 

4 6 

4 6.5 

2 6 

2 4 

2 4 

1 4 

5.5 2 

4 7 

1 6 

6 8 

2 5 

2 1 

4 2 

9 

5 

6 

6 

8 

8 

6 

6 

5 

2 

9 

7 

7 

9 

6 

3 

-~ 

3.5 

8 

8 

6 

3 

9 

9 

5 

6 

5.5 

8 

9 

9 

7 

9 

9 

110.5b 50* 68 66 81 54b 74.5 102 114b 

a Read only at 24 hr. b Outside limits; CQ.,,~ = 58.9 to 110.1. 

TABLE 52 

SKIN-INTRALABORATORY SAMPLE RANK-REFERENCE METHOD 

Laboratory 

No. 

- 

2 

4 

5 

7 

8 

9 

10 

11 

12 

13 

14 

18 

19 

21 

22 

23 

24 

25 

26 

27 

30 

31 

-E F 

3 1 

7 4 

5 2 

6 5 

5 1 

6 2 

10 2 

7 2 

10 2 

6 2 

7 2.5 

8 6 

4 2 

6 6 

6.5 2 

8.5 3 

6.5 2 

6 2 

9 1 

8.5 2 

7 4 

7 1 

Material 

G I J K L M N 

8.5 10 6 5 2 4 8.5 

8 6 3 2 1 5 9 

9.5 7.5 4 3 1 6 7.5 

10 4 2 3 1 9 7.5 

6.5 6.5 3 4 2 8 10 

5 9 4 3 1 8 10 

8 7 5 4 1 3 6 

9 10 4 5 1 3 8 

8 9 6 4 1 3 7 

7 5 4 3 1 9 10 

9 10 2.5 5 1 4 6 

9.5 9.5 5 2 1 3 7 

7.5 6 5 3 1 7.5 9 

6 6 6 6 6 1 6 

6.5 5 4 3 1 8 9.5 

8.5 6 4 2 1 5 10 

10 8.5 3 4 1 6.5 8.5 

9 10 3 5 1 4 7 

5 7 10 2.5 2.5 4 6 

8.5 7 4 3 1 5 10 

9.5 6 2 3 1 8 9.5 

6 8 5 3 2 4 10 

- 

0 

7 

10 

9.5 

7.5 

9 

7 

9 

6 

5 

8 

8 

4 

10 

6 

9.5 

7 

5 

8 

8 

6 

5 

9 

Sum of 

ranks 149 56.5” 174.5” 163” 94.5 77.5” 31.5” 118 182” 163.5” 

’ Outside limits; OL,,.~~ = 79.4 to 162.4. 
1NTERLABORATORY EYE AND SKIN COMPARISONS 331 

On the basis of the 9 pertinent samples, the following laboratories lacked significant 

or had negative correlation (Table 56) between their reference and their nonreference 

eye procedures : 

Coefficient of rank correlation Nonreference 

Type of _~__._--- test Draize or 

Laboratory laboratory 24-Hr basis Median of median basis FHSA type 

5 C 0.388 Yes 

7 I 0.046 0.042 Yes 

8 T 0.415 0.579 Yes 

11 I 0.288 0.383 No 

13 T -0.812 -0.617 Yes 

14 C 0.529 Yes 

22 C 0.188 0.000 Yes 

24 T 0.542 Yes 

30 C 0.392 0.462 Yes 

31 I 0.433 No 

TABLE 53 

SKIN-INTRALABORATORY SAMPLE RANK-NONREFERENCE METHOD 

Laboratorv 

Material 

No. ” E F G I J K L M N 0 

4 9 2 8 4 5 3 1 6 7 10 

5 6 2 10 8 3 4 1 5 7 9 

7 5 1.5 10 6 3 4 1.5 9 7 8 

8 5 2 8 7 3 4 1 6 9.5 9.5 

9 8.5 2 7 5 4 3 1 6 10 8.5 

10 9 2 10 8 4 5 1 3 6 7 

11 6 3 9 4 5 2 1 7 8 10 

12 8 2.5 9 10 2.5 5 2.5 2.5 6 7 

13 10 1 6 5 4 3 2 7 8 9 

14 5 3 9 8 2 1 4 7 10 6 

21 7 7 7 3 7 7 7 1.5 1.5 7 

22 5 2 6.5 6.5 3 4 1 8 9.5 9.5 

23 8 1.5 10 9 5.5 3 1.5 4 7 5.5 

24 5 2 9.5 7.5 3 4 1 6 9.5 7.5 

25" 6.5 2.5 8 6.5 4 5 1 2.5 9.5 9.5 

25b 10 1 9 7 5 6 3 2 4 8 

26 4 6 2 6 8.5 1 3 6 8.5 10 

3 21 6 1 9 10 3 4 2 5 8 7 

30 7 5 10 7 3 4 1 7 9 2 

31 7.5 1.5 4 5.5 3 1 2 9 10 5.5 

Sum of 

ranks 137.5 56.5‘ 161" 133 80.5 73 38.5' 109.5 155' 155.5' 

o Guinea pig-FHSA method (21 Code of Federal Regulations). 

b Guinea pig-cuff method (Roudabush et al., 1965). 

c Outside limits; CQ,.~~ = 71.0 to 149.0. 
TABLE 54 

CORRELATIONOF INDIVIDUAL LABORATORY RANKINGOF SAMPLES WITH OVERALL TNTRALABORATORY RAN

Eye test (with sample G) Eye test (without sample 

- ~__ _

Laboratory 

Reference Nonreference Reference Nonre

-- -~___ 

No. and 

-~___- ___--. 

24-Hr Median of Median of 24-Hr Median of Med

type” median medians medians median medians me

--. _. 

Coefficient of rank correlation of sample ranks for individual labora

IT 0.561b 0.733 0.392b 0.381b 0.619” 0

2G 0.300b 0.512b - 0.857 0.970 

4c -0.37gb 0.133b 0.221b -o.133b 0.61gb 0

5c 0.471b 0.283b 0.417b 0.286b 0.214b 0

71 0.529b 0.700 0.533b 0.327b 0.571b 0

8T 0.37gb 0.900 0.438b 0.113b 0.857 0

91 0.800 0.917 0.783 0.714 0.881 0

1oc 0.833 0.667 0.633 0.810 0.738 0

111 0.629 0.817 0.733 0.470b 0.738 0

12T 0.746 0.783 0.637b 0.762 

- 

13T 0.204’ 0.383b 0.283’ -0.137b 0.119b 0

14c 0.688 0.617 0.379b 0.934 0.690 0

16T O.446b 0.746 0.733 0.208b 0.637b 0

18C 0.588b 0.862 

- 0.41 lb 0.899 

19c 0.188b 0.754 --0.161b 0.649 

- 

21G 0.5796 0.929 - 0.518” 0.899 

22c 0.546b 0.183b 0.767 0.899 0.429b 0

23T 0.800 0.800 - 0.714 0.714 

24T 0.558b 0.483b 0.417b 0.36gb 0.262b 0

251 0.767 0.717 - 0.667 o.595b 

26G 

- - - - - 

271 0.854 0.667 0.817 0.792 0.524b 0

29c 0.721 0.883 - 0.613b 0.833 

3oc 0.250b 0.327b 0.567b 0.429b 0.45Sb 0

311 0.454b 0.583b 0.500b 0.667 0.762 0

NS: total No. of labse 15124 8124 lo/16 15124 11/24 

a See Table 1. h Rank correlation coefficient nor signi

c Guinea pig-FHSA method (21 Code of Federal Regulations). d Guinea pig-cuff method (Roudabush 

e Number of laboratofies with nonsignificant correlations: total number of laboratories. 
TABLE 55 

SUMMARY OF RESULTS OF INTRALABORATORY SAMPLE COMPARISONS 

Material 

Eye test (with sample G) Eye test (without sample G) 

Non- - Non- 

Reference reference Reference reference Skin test 

24-Hr M,e,“dii‘,“,;f Ee$hn;f 24-Hr 

median median 

FeddiFl$f M,eeddsof Non- 

Material Reference reference 

Column 1 2 3 4 

Sum of ranks 

5 6 7 8 

Sum of ranks 

A’ 139.0 155.0 110.5b 118.0 

F 93.5 77.0b 50.0b 76.5 

G 65.0 69.0b 68.0 - 

J 109.5 89.5 66.0 92.5 

K 166.00 131.5 81.0 145.0b 

L 95.5 84.0 54.0s 18.5 

M 103.5 120.5 74.5 84.5 

N 149.5 170.5b 102.0 131.5 

Pa 158.5 183.0b 114.0b 137.5 

133.0 

61.0b 

98.0 

42.0b 

- - 

74.5 58.5 

112.5 71.0 

69.0b 45.5 

102.5 65.5 

150.5b 93.0 

161.0* 102.5 

EC 

F 

G 

J 

K 

L 

M 

N 

OC 

1’ 

149.0 137.5 

56.5b 56.5’ 

174.5” 161.0b 

94.5 80.5 

77.5b 73.0 

31.5’ 38.5b 

118.0 109.5 

182.0b 155.0b 

163.5b 155.5b 

163.0b 133.0 

No. of 

labOratOrieS 24 24 16 24 24 16 22 20 

95 7: limits 80 to 160 80 to 160 59 to 110 73 to 143 73 to 143 45 to 99 79 to 163 71 to 149 

n Not used as a pertinent material for skin test. 

b Outside 95 ‘A limits. 

c Not used as a pertinent material for eye test. 

Coefficient of rank correlation: 

column 1 vs. 2 +0.883b 

column 1 vs. 3 +0.750* 

column 2 vs. 3 +0.883” 

column 7 vs. 8 +0.952b 
TABLE 56 

EYE IRRITATION TESTS-SPEARMAN RANK COEFFICIENT OF CORRELATI

(17 LABORATORIES WHICH RAN BOTHTHEREFERENCEAND ANONREFERENCETEST; 24 LA

REFERENCE TEST-9 OR 12 PERTINENT SAMPLES) 

Rank coefficient of correlation 

Nonreference vs. Reference 

Laboratory 

Reference median Reference median 24-Hr median vs. 

No. and 

at 24 hr of medians median of medians 

type’ 9 Samples 12 Samples 9 Samples 12 Samples 9 Samples 12 Samples 

1T 0.842 0.970 0.942 0.960 0.733 0.881 Like 

4c 0.800 0.911 0.846 0.928 0.712 0.879 Draiz

5C 0.388’ 0.741 0.967 0.981 0.28Sb 0.680 

71 0.046b 0.2016 0.042b 0.27Sb 0.971 0.948 

ST o.475b 0.736 0.579b 0.780 0.604 0.834 

91 0.775 0.906 0.983 0.993 0.683 0.867 

1oc 0.833 0.902 0.683 0.839 0.817 0.923 

111 0.28Sb 0.694 0.383b 0.740 0.746 0.888 

13T -0.812” -0.0336 -0.617” 0.131b 0.546b 0.808 

14c 0.786 0.897 0.529b 0.797 0.829 0.928 

16T 0.729 0.879 0.771 0.904 0.854 0.932 

22c 0.188b 0.652 O.OOOb 0.580 0.879 0.942 

24T 0.542b 0.801 0.892 0.955 0.483b 0.776 

271 0.721 0.820 0.650 0.776 0.820 0.925 

3oc 0.392” 0.687 0.462’ 0.670 0.745 0.864 

311 0.879 0.948 0.433b 0.760 0.496b 0.788 

21G 

2G 

12T 

19c 

18C 

23T 

2% 

29c 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

0.896 0.941 

0.688 0.839 

0.746 0.893 

0.842 0.892 

0.292h 0.687 

0.833 0.930 

0.850 0.937 

0.879 0.949 

2 to 

FHSA 

FHSA 

Like 

Like 

Like 

Two d

Diff

FHSA 

Like 

Not r

Draiz

Orgin

1959 

FHSA 

Differ

Dif
TABLE 56-cotztittued 

Rank coefficient of correlation 

Nonreference vs. 

Reference median at 24 hr Reference median of medians 

- 

9 Samples 12 Samples 9 Samples 12 Samples 

25th Percentile Q’ 0.338 0.690 0.408 0.705 

Median Qz 0.642 0.810 0.614 0.788 

75th Percentile Q3 0.793 0.904 0.869 0.942 

ao.05 0.600 0.506 

ao.01 0.783 0.712 

R See Table 1. 

b Correlation not significantly different from zero correlation (P > 0.05). 

’ Significant negative correlation (P < 0.05). 
336 WEIL AND SCALA 

TABLE 57 

SKIN IRRITATION TESTS; SPEARMAN RANK COEFFICIENT OF CORRELATION 

(19 LABORATORIES WHICH RAN BOTH THE REFERENCE AND A NONREFERENCE 

TEST-10 OR 12 PERTINENT SAMPLES) 

Rank coefficient 

Laboratory of correlation 

No. and ~ 

type” 10 Samples 12 Samples Brief description of nonreference test 

4c 

5C 0.970 0.895 

71 0.879 0.930 

8T 0.945 0.955 

91 0.803 0.869 

1oc 0.927 0.918 

111 0.515’ 0.580 

12T 0.836 0.885 

13T 0.830 0.746 

14c 0.621 0.710 

21G 0.779 0.712 FHSA. Covered with parafilm and adhesive tape and 

22c 0.961 0.948 

23T 0.821 0.836 

24T 

251 

26G 

271 

3oc 

311 

25th 

Percentile 

Ql 

Median Qz 

75th Percentile Qs 

a0.05 

a0.01 

0.867 0.918 

0.933 0.928 

0.845 0.691 

0.709 0.743 

0.521’ 0.701 

0.852 0.895 

0.912 0.932 

0.406’ 0.502’ 

0.744 

0.840 0.877 

0.920 0.923 

0.564 0.506 

0.746 0.712 

FHSAb test using 93 to 4 kg; intact and abraded; 

reference $2 to 3 kg 

“Appraisal of Safety of Chem.“-Draize (1959) 

method. Abraded; no plastic cover. 

FHSA 

Rubberized cloth cover; skin rinsed after cover removed 

FHSA intact and abraded. Elastoplast and filter cloth 

cover-snug 

FHSA 

10 repeated applications over 14 days; cotton pad; 

different scoring system 

Abraded, covered with Elastoplast. Similar to FHSA 

FHSA grading but not covered-no sleeve 

Draize (1944). Abraded and nonabraded; polyethylene 

cover 

rubber dam. Read at 24 hr 

FHSA 

Abraded; tape, SARAN, then masking tape-snug, 

more occluded 

Practically identical to reference procedure 

Guinea pig-FHSA method 

Guinea pig-cuff method 

No cover; different scoring system 

Like lab 5 

FHSA 

0.01 ml uncovered; read at 24 hr only; different scoring 

system 

0.711 

a See Table 1. 

b FHSA method (21 Code of Federal Regulations). 

c Correlation not significantly different from zero correlation (P > 0.05). 
INTERLABORATORY EYE AND SKIN COMPARISONS 337 

Thus 10 of the 16 laboratories which ran both the reference and nonreference procedures had some lack of significant correlation. In only 2 of these 10 was the nonreference procedure really different, in method of application and/or in scoring, from 

the reference procedure. Note that, while none of the 3 governmental laboratories is in 

the above list, none of them could have been. Two did not attempt a nonreference test 

(laboratories 2 and 21) and one, laboratory 26, did not attempt either eye procedure. In 

all, 8 laboratories did not try a nonreference test as several of them recognized the close 

similarity between the quantity of material applied and the scoring method of the 

reference procedure and of the Federal Hazardous Substances Act (FHSA) and the 

Draize methods. 

With this similarity in mind, it is, indeed, remarkable that 8 laboratories, listed above, 

did not obtain a significant, positive, correlation in their own laboratory, between their 

nonreference (FHSA or Draize) and their reference procedures. Two of these 8 (laboratories 7 and 22) had practically zero correlation, while laboratory 13 had negative 

correlation. The ranks, at 24 hr, of the 9 pertinent samples for these 3 laboratories 

are repeated in the accompanying tabulation. 

Laboratory 7 Laboratory 22 Laboratory 13 

--__. -__ 

Non Non- NonSample Reference reference Reference reference Reference reference 

A 3 8.5 8 

F 2 1.5 1 

G 1 8.5 7 

J 5 3 4 

K 4 1.5 9 

L 6 4 3 

M 7.5 6 2 

N 7.5 6 5.5 

P 9 6 5.5 

2 

6 

I 

9 

7.5 

7.5 

4 

4 

4 

Coefficient of correlation : 

With G 0.046 

Without G 0.464 

0.188 -0.812 

0.220 -0.732 

The lack of correlation was not associated entirely with sample G, an inconsistent 

sample between laboratories, although it is remarkable that this could have been ranked 

most irritating by the reference tests in laboratories 7 and 13 and least irritating by their 

nonreference, practically identical, procedures. 

For the skin, reference Z)USUS nonreference procedures in the same laboratories, 

attempted by 19 laboratories, only 3 had nonsignificant correlations. This is not unexpected, as the nonreference procedure in most laboratories was the FHSA or Draize 

procedure. The laboratories with nonsignificant correlations were 11, 26, and 31. 

Laboratories 26 and 31 used uncovered application, laboratory 11 used 10 repeated 

applications, and all 3 had different scoring systems from the reference or from FHSA. 
338 WEIL AND SCALA 

Laboratory 13 used FHSA grading, but no cover, and laboratory 25 used two procedures, both with guinea pigs instead of rabbits. In these, as well as in the laboratories 

other than 11, 26, and 3 I, the good correlation indicated the close similarity between 

results of the FHSA and the reference procedures, even though no necrosis was scored 

on the former and no abrasions were used on the latter. This being true, it is, indeed, 

remarkable how some of these same laboratories were outliers when compared by the 

reference procedure to the other laboratories, as previously described. 

F, Degree of Irritation 

The results of the laboratories were compared to determine the degree of homogeneity that they would obtain in rating the tested materials as “irritants” or “nonirritants.” The definitions used for this designation were those of regulations under the 

FHSA Code of FederaI Regulations: for the eye test the number of rabbit eyes 

with “positive” scores and for the skin test a primary irritation index of 5.0 or 

higher. 

The degree-of-irritation ratings on the eye test, in 24 laboratories, are presented in 

Table 58. The nonreference procedure results (Draize-type tests) were used in 16 laboratories and the reference procedure only in 8. In 8 laboratories the personnel presented 

their own irritancy ratings, and these were used. In the other 16, the laboratories presented no degree-of-irritancy rating; therefore, one of the authors rated the recorded 

readings of the individual rabbits as “positive” or “negative.” 

The degree-of-irritancy ratings on the skin test are presented in Table 59. As the reference procedure did not involve abrasion of one-half of the patch areas, only the results 

of the laboratories which used the FHSA test as their nonreference procedure could be 

used. 

In both Tables 58 and 59, the ratings of the materials which were not used in the preceding sections of this report, the low-discriminatory materials, are listed. The frequencies of nonirritant, questionable, or irritant ratings for the eye test and of the degree 

of nonirritancy or irritancy for the skin test are summarized for all materials in Table 60. 

On the eye, only one material, B, was rated the same, nonirritant, in all laboratories. 

However, on the skin, 4 of the 6 low-discriminatory materials (A, B, D, and H) were 

consistently rated nonirritating. 

It is notable that this all-or-none word classification can be determined quite differently in different laboratories. Material N on the eyes was rated nonirritant or 

questionable by 7, but was rated an irritant by 17 laboratories; material 0 was rated an 

irritant by 6 of the 24 laboratories. On the skin, material F was rated A or B (nonirritant) 

by 8, and C by 8 laboratories, a 50: 50 division in ranking as an irritant or not. Material 

L was classified C (a skin irritant with a score above 5) by 1 I laboratories, but classified 

nonirritating (A or B) by 5 laboratories. Similarly, K was rated an eye-irritant by 21 but 

a nonirritant by 3 laboratories. 

Obviously, therefore, as noted in the previous, more quantitative discussions of the 

reference-procedure results, the current FHSA eye and skin tests, as used by a variety of 

laboratories, often did not give similar results. Thus the use of this type of irritant or 

nonirritant category designation, using word-descriptions that have existed for years 

(Draize ratings for eye or skin irritation), can be quite unreliable. 
INTERLABORATORY EYE AND SKIN COMPARISONS 339 
TABLE 59 

DEGREE-OF-IRRITATION RATINGS-SKIN TEST 

LaboraMaterial 

tory E 

No.“ 

F G I J K L M N 0 A B 

Degree-of-irritation rating on nonreference test (FHSA)b 

4 A B A B 

5 B B A A 

7 A B A A 

8 A B A A 

9 A C B B 

10 A B A A 

12 B C B B 

13 A B A B 

14 B C A A 

21 A A A B 

22 A C A A 

23 B C A A 

24 B C A A 

25 A C A B 

27 A C A A 

30 A A A A 

B B C A A A A A 

B B B B A A 

A A B A A 2 A A 

B B B A A A A A 

C C C B A A A A 

B B B A A A 

c c c : C B A A 

c c c B A A A 

c c c : A A A A 

A A A B B A A A 

C B C A A A A A 

B B C B B B A A 

B B C A A A A A 

B B C C C A A A 

B B C A A A A 

B B C A A B A 

a Reference test only run by laboratories 2, 18, and 19. Nonreference test was not similar to FHSA procedure in 

Terms used by laboratories 

b A = combined average of 2.0 or lower or negative or mild 

B = combined average of 2.1 to 4.9 or moderate 

- 

C = combined average of 5.0 or higher or severe or strong (primary irritant by FHSA definition). 
TABLE 60 

FREQUENCY THAT MATERIALS WERE RATED AS EYE OR SKIN IRRITANTS 

Eye 

Material Code 

Non- Questionirritant (Nl) able Irritant (I) 

95 % Ethanol 

Isopropyl myristate 

Triethanolamine lauryl sulfate; 

46 % aqueous 

Peroxide; 20 vol cream 

Triethanolamine 

Ethoxylated lauryl alcohol 

Decaethoxy oleyl ether 

Linoleic diethanolamide 

n-Butyl alcohol 

Methyl ethyl ketone 

Methyl isobutyl ketone 

Ethylene glycol monoethyl ether 

Propylene glycol 

2 % Formaldehyde 

Glycerin 

Aluminum chlorhydroxide; 

50% aq. 

A 3 2 19 

E 22 2 0 

F 1 0 23 

G 

I 

J 

K 

L 

M 

N 

0 

P 

z 

D 

H 

0 I 23 

18 3 3 

4 2 18 

3 0 21 

1 1 22 

2 2 20 

4 3 17 

14 4 6 

3 2 19 

20 0 0 

18 1 1 

19 1 0 

15 4 0 

Skin 

- 

A B 

4 2.1 to 4.9 

NI NI 

16 0 

11 5 

2 6 

14 2 

10 6 

2 9 

2 10 

1 4 

7 6 

11 3 

13 3 

13 3 

14 0 

13 1 

14 0 

14 0 

n Minimum, since “questionable” is rated here as nonirritant. 
342 WEIL AND SCALA 

G. Comparison of Eye and Skin Rating in the Same Laboratories 

It is of interest to compare the laboratories that performed both the reference eye and 

skin tests to determine whether laboratories that ranked relatively high on the one also 

tended to rank high on the other. The relative ranks on both tests are presented in Table 

61. The coefficient of rank correlation, for the 21 laboratories which performed both 

tests, was +0.544, statistically significantly different from zero correlation. Some 

laboratories, therefore, which ranked low (a small rank number indicates relatively 

severe readings) on the eye test (e.g., laboratory 12 ranked 2) also ranked low on the skin 

test (laboratory 12 here ranked l-the most severe reading). Laboratory 27, contrariwise, ranked 20th of 21 laboratories on both the eye and skin test. 

TABLE 61 

COMPARISON OF RELATIVE RANK OF LABORATORIES 

ON BOTH THE EYE AND SKIN TESTS 

Relative rank” 

Relative ranksb if both eye 

and skin tests were run 

Laboratory 

No. Symbol Eye test Skin test Eye test Skin test 

4 C 2” 18 1 17 

12 T 3” 1’ 2 1 

14 C 4” 2” 3 2 

10 C 6 5 4 5 

31 I I 7 5 7 

22 C 8 15 6 14 

2 G 9 12 7 11 

9 I 10 11 8 10 

11 I 11 3 9 3 

23 T 12 8 10 8 

25 I 13 6 11 6 

21 G 14 22” 12 21 

5 C 15 10 13 9 

19 C 16 13 14 12 

24 T 18 14 15 13 

7 I 19 16 16 15 

13 T 20 4 17 4 

18 C 21 19.5 18 18.5 

8 T 22 17 19 16 

27 I 23” 21’ 20 20 

30 C 24” 19.5 21 18.5 

29 C 1C 

1 T 5 

16 T 17 

26 G - 

- 

- - - 

- - 

9 -- 

(I Rank of 1 assigned to the laboratory with the smallest sum of ranks; rank of 1 (for each material) 

assigned to the laboratory with the highest (most severe) score. 

b Coefficient of rank correlation = +0.544; 0.01 > P > 0.001. 

c P < 0.05 for sum of ranks in interlaboratory comparison of reference method. 
INTERLABORATORY EYE AND SKIN COMPARISONS 343 

In 4 laboratories, there was a considerable difference in the relative rank in the eye and 

skin tests : 

Relative rank 

Laboratory Eye test Skin test 

4 1 17 

22 6 14 

21 12 21 

13 17 4 

If the results of these 4 laboratories had been omitted, and the remaining 17 reranked, 

the correlation coefficient would have been raised from +0.544 to +0.899, a considerable 

increase. However, it is notable that, while the majority of laboratories that read relative 

high scores on the one test also tended to read high on the other, this was not universally 

true. 

The scores recorded for the low-differentiating materials are presented in Table 62. 

TABLE 62 

SCORES RECORDED FOR LOW-DIFFERENTIATING MATERIALS ON REFERENCE TESTS 

Material designation 

Laboratory B C D E H I 0 A BCDHP 

No. -_ 

Eye test-24-hr median Skin test 

-___ 

1 

2 

4 

5 

7 

8 

9 

10 

11 

12 

13 

14 

16 

18 

19 

21 

22 

23 

24 

25 

26 

27 

29 

30 

31 

1 622928 

0 200732 

0002256 

--- 6 -- 6 18 

0 0 0 5 0 10 1 

0000203 

0000201 

--- 7- 4 3 

--- 2- 2 2 

0 2 2 2 3 6 26 

0000112 

0 0 0 0 2 3 24 

0000123 

0 14 1 0 6 0 6 

--- O- 6 7 

0000243 

0 1 0 2 2 6 3 

0 1 0 1 4 2 0 

0000235 

2 0 1 o- 2 2 

----__ 

-ioooooo 

0000062 

1 0 1 0 4 8 5 

0000006 

- 

0.0 

0.0 

0.1 

0.0 

0.0 

0.0 

0.0 

0.1 

0.0 

0.0 

0.0 

- 

0.0 

0.4 

0.0 

0.0 

0.1 

0.0 

0.4 

0.0 

0.0 

- 

0.0 

1.0 

- - - 

0.0 0.0 0.0 

0.1 0.0 0.1 

- 

0.0 

0.0 

0.0 0.0 0.0 

0.0 0.0 0.0 

0.4 0.0 0.2 

- 

0.0 

0.0 

0.0 

- - - - 

0.2 0.4 0.4 0.2 

1.3 0.0 0.0 0.4 

0.0 0.0 0.0 2.4 

0.0 0.1 0.0 0.0 

- - - 

0.0 0.0 0.0 

0.0 0.0 0.0 

0.4 0.0 0.0 

0.5 0.2 0.2 

0.5 0.0 0.2 

0.9 0.0 0.1 

0.0 0.0 0.0 

0.0 0.0 0.0 

0.0 0.0 0.0 

0.8 0.0 0.0 

- 

0.1 

- 

0.0 

0.1 

0.0 

0.0 

0.0 

0.0 

0.1 

- 

0.2 

0.0 

0.1 

0.0 

1.0 

0.6 

0.2 

0.3 

0.7 

1.5 

2.6 

1.1 

2.1 

- 

0.2 

0.4 

0.0 

0.0 

0.1 

0.0 

1.0 

1.0 

0.0 

- 

0.6 

0.0 
344 WEIL AND SCALA 

H. Retest, Using Reference Procedures, in Two Laboratories 

Two laboratories were arbitrarily selected and graciously agreed to rerun the 

reference eye and skin tests under the following conditions: 

1. Aliquots of the same samples of the materials used in the first run were tested for 

microbial content, and, found negative, were then used in the rerun. 

2. An independent observer (“0”; one of the Steering Committee) participated in the 

retest in both laboratories. 

3. The skins of the rabbits selected for use were clipped the day before application of 

the materials and were assigned by randomization into 2 groups. An investigator (I) in 

each laboratory (the same one who ran the first test, if possible) treated his rabbits just 

prior to the time the independent observer treated his. 0 observed the investigator, but 

made no comment at the time on his technique. Then 0 treated his rabbits. The I at each 

laboratory treated 12 and 0 treated 12 other rabbits as follows: 

a. Eye test 

1. The reference procedure was used. 

2. I treated 4 eyes (2 right and 2 left) per sample, using materials F, J, K, L, M, and 

N. 

3. 0 also treated 4 eyes (2 right and 2 left) per sample, using the same materials. 

4. The next day, approximately 18 to 24 hr post-treatment, I read, graded, and 

recorded the results of the rabbits he treated, and 0 read, graded, and recorded 

the results of his treated rabbits. Then 0 read, graded, and recorded the Itreated rabbits and I read, graded, and recorded the results of the O-treated 

rabbits. 

b. Skin test 

1. The reference procedure was used. 

2. I treated 6 rabbits for each sample, 4 samples per rabbit, 8 samples altogether: 

E, F, I, J, K, L, M, and N. 

3. 0 also treated his 12 rabbits as in step 2. 

4. The readings and recording of results were independently performed by I and 

0 as in step 4 in the eye retest procedure. 

c. The investigator in each of the 2 laboratories will henceforth be denoted by 

letters other than I; each indicative of whether the same one treated and read in 

each test. 

0 was requested to write his comments on any differences in interpretation of procedure techniques he observed. 

The 2 laboratories selected for retest were laboratories 27 and 12. Reference to Table 

61 indicates that laboratory 27 ranked 23rd of 24 laboratories on the eye test and 21st of 

the 22 laboratories on the skin test, while laboratory 12 ranked 3rd and 1st on the eye 

and skin tests, respectively. Thus, laboratory 27 tended to read results less severely and 

laboratory 12 more severely than the majority of the other laboratories in this collaborative study. 

The results will be discussed separately for each of the eye and skin tests in each of the 

2 laboratories and then the readings in both laboratories will be compared. 
INTERLABORATORY EYE AND SKIN COMPARISONS 345 

1. Eye test-Laboratory 27. The median scores are presented in Table 63 for each of 

the 6 materials applied and/or read by 0, the independent observer, and by R, the same 

technician in laboratory 27 who originally applied the materials and read the results in 

TABLE 63 

SCORES AND COMPARISONSOF REFERENCEEYEPROCEDURE IN LABORATORY 27 

WHERE Two TECHNICIANS APPLIED MATERIALS AND/OR READ RESULTS 

Median score for material 

Applied Read __.- 

Line by by F J K L M N 

1 0” 0 29 18 15.5 25.5 33.5 43 

2 0 R” 38 28 2 40.5 22.5 34 

3 R R 18 21.5 24 20 24.5 16.5 

4 R 0 28.5 31.5 25 23.5 24.5 26 

S’ R R 24 9.5 4 20 24 2 

l-l 0 0 2 4 3 2 1 1 

2-1 0 R 1 2 4 1 4 2 

3-l R R 4 3 2 4 2.5 4 

4-l R 0 3 1 1 3 2.5 3 

Rank for lines 1 to 4 

Rank for lines 1 to 5 

Sum of 

ranksQ 

13 

14 

19.5 

13.5 

Sum of 

rankse 

l-2 0 0 2 4 3 2 1 1 13 

2-2 0 R 1 2 5 1 5 2 16 

3-2 R R 5 3 2 4.5 2.5 4 21 

4-2 R 0 3 1 1 3 2.5 3 13.5 

5-2 R R 4 5 4 4.5 4 5 26.5 

Signed rank test comparisons 

First > second First c second 

(+I (-) Tie 

1 vs. 2 00 US. OR 3 

1 vs. 3 00 vs. RR 4 

1 vs. 4 00 vs. RO 4 

2 vs. 3 OR us .RR 3 

2 vs. 4 OR vs. RO 3 

3 vs. 4 RR vs. RO 0 

3 vs. 5 RR vs. RR 4 

Mean values 

compared where : 

- 0 or R applied 4 

0 or R read 5 

3 0 

2 0 

2 0 

3 0 

3 0 

5 1 

1 1 

2 0 14.5 6.5 2 

1 0 17 4 2 

Sum of signedS 

T ranks - ranks 

cc0.s5 limit for 

smaller sum 

10.5 10.5 

17 4 

12 9 

12 9 

12 9 

0 159 

13 2 

’ 0 designates an independent observer, R an investigator from laboratory 27. 

b Previous results from laboratory 27. 

= ccg,05 = 8 to 22. 

d Rank of 1 given to most severe reading; therefore, smaller sum of ranks is more severe than larger. 

e c(,-,.,,~ = 9 to 27. 

’ Larger sum of signed ranks indicates more severe reading than smaller sum. 

BP cc 0.05. 
346 WEIL AND SCALA 

TABLE 64 

SCORES AND COMPARISONS OF REFERENCE SKIN PROCEDURE IN LABORATORY 27 

WHERE Two TECHNICIANS APPLIED MATERIALS AND/OR READ RESULTS 

Primary irritation score for material 

Applied Read 

Line -by by E F I J K L M N 

56 

l-l 

2-1 

3-l 

4-1 

l-2 

2-2 

3-2 

4-2 

5-2 

0” 

0 

R 

R 

R 

0 

0 

R 

R 

0 

0 

R 

R 

R 

0 

R” 

R 

0 

R 

0 

R 

R 

0 

0 

R 

R 

0 

R 

- 

0.17 1.67 1.17 1.83 2.17 5.50 

1.00 1.67 1.00 2.50 3.33 4.50 

0.67 1.50 1.33 0.67 2.17 17.33 

0.83 3.67 0.83 2.00 1.50 20.33 

0.1 4.0 0.2 1.9 2.0 5.0 

Rank for lines 1 to 4 

4 2.5 2 3 2.5 3 

1 2.5 3 1 1 4 

3 4 1 4 2.5 2 

2 1 4 2 4 1 

Rank for lines 1 to 5 

4 3.5 2 4 2.5 3 

1 3.5 3 1 1 5 

3 5 1 5 2.5 2 

2 2 4 2 5 1 

5 1 5 3 4 4 

0.67 0.00 

0.33 0.00 

1.67 0.83 

1.00 1.50 

0.8 0.0 

Sum of 

ranksc’d 

3 3.5 

4 3.5 

1 2 

2 1 

23.5 

20.5 

19.5 

17.0 

Sum of 

rankse 

4 4 27.0 

5 4 23.5 

1 2 21.5 

2 1 19.0 

3 4 29.0 

1 vs. 2 00 vs. OR 

1 vs. 3 00 us. RR 

1 vs. 4 00 vs. RO 

2 vs. 3 OR vs. RR 

2 vs. 4 OR vs. RO 

3 vs. 4 RR vs. RO 

3 vs. 5 RR vs. RR 

Mean values 

compared where : 

8 13 2 

8 20 4 

8 28 6 

15.5 20.5 6 

12 24 6 

10 26 6 

23 13 6 

0 or R applied 2 5 1 6.5 21.5 4 

0 or R read 4 4 0 22.5 13.5 6 

Signed rank test comparisons 

Sum of signedf 

First > second First c second tc0.05 limit for 

(+I C-1 Tie -t ranks - ranks smaller sum 

- 

’ 0 designates an independent observer, R an investigator from laboratory 27. 

b Previous results from laboratory 27. 

c LQ.05 = 12 to 38. 

d Rank of 1 given to most severe reading; therefore, smaller sum of ranks is more severe than larger. 

‘? c(o.tJ5 =13 to 35. 

f Larger sum of signed ranks indicates more severe reading than smaller sum. 
INTERLABORATORY EYE AND SKIN COMPARISONS 341 

the first test in this laboratory. On line 5 in this table are presented the previous readings 

by R. The median scores were much lower previously than in the retest, especially for 

samples J, K, and N. When lines 1 to 5 were ranked, the sum of ranks (line 5-2) for the 

previous readings were close to being significantly different from all of the others (ranks 

of 4 to 5 for each sample, with the current application and reading by R being a close 

second (line 3-2). Therefore, the tendency was, previously and in the retest, for R to score 

less severely than others. When R applied, and 0 read (line 3), this tendency disappeared. 

Therefore, the difference appeared to be in the reading, not the application. 

The signed rank test was used to more powerfully delineate differences or similarities 

in the paired application and reading procedures. One statistically significant difference 

was found, for RR (applied by Rand read by R) versus RO (applied by Rand read by 0). 

Here, for 5 of 6 materials, R scored the cornea1 injuries less severely than O-the previous overall tendency of this laboratory. The trend (this term, trend or tendency, will 

be used when the results were close to, but not, statistically significant) of lines 1 versus 3 

(00 versus RR) were also in this direction. Similarly 3 uersus 5, the current RR versus 

the previous RR, again indicated that the current results were read as more severe corneal injury than the previous. 

When the scores of the 0 applications were compared with those of the R applications, as well as when the 0 readings were compared with the R readings, the R 

scores were less severe in each case; as stated before, this was the previous tendency of 

this laboratory. 0 did not observe any difference in technique or interpretation of the 

protocols of the reference procedure by R, with the possible exception that 0 noted 

more iritis than did R. 

2. Skirt test-Laboratory 27. The primary irritation scores are presented in Table 64 

for each of the 8 materials applied and/or read by 0 and by R. As in the eye test, the 

previous readings (line 5) tended to be less severe than the current ones (line 3). In the 

signed rank comparisons, the tendency was for the current results to be more severe 

when R applied than when 0 applied. 0 observed a significant departure from protocol 

in the technique of R. The Saran sleeve was left double, placed over the patches and 

taped tightly to the animal by wrapping masking tape completely around the rabbit. 

This would allow drastic exposure to test chemicals, much in excess of that intended in 

the protocol. This obviously occurred in sample L, where necrosis resulted from the R, 

but not from the 0, application. The rabbits treated by 0 were read, for material L, as 

reversible eschar (which 0 remarked would have to be judged later than 24 hr after 

treatment to determine the presence or absence of necrosis; all readings in the retest 

were made only at 24 hr). On the line 1 versus 4 comparison, 00 versus RO, the trend 

was, again, toward more severe readings when R applied. 

3. Eye test-Laboratory 12. The scores and comparisons of the reference eye procedure in laboratory 12, when applications and readings were made by 0 or by N, are 

presented in Table 65. Note that technician N was not the same as the one who previously applied (Q) or read (D) the results in laboratory 12. As mentioned earlier, the 

previous readings of results in laboratory 12 were more severe than in the majority of the 

other laboratories. 

In the retest (on lines l-l to 4-l), NN (N applied and N read) results were definitely 

(statistically significantly) the most severe, with NO (N applied, 0 read) results significantly the least severe; the 00 combination was similar to that for NO. 
348 WEIL AND SCALA 

TABLE 65 

SCORES AND COMPARISONS OF REFERENCE EYE PROCEDURE IN LABORATORY 12 

WHERE Two TECHNICIANS APPLIED AND/OR READ RESULTS 

- 

Median score for material 

Applied Read 

Line by by F J K L M N 

1 0” 0 i6 14.5 8 24.5 18 11 

2 0 N” 34.5 34 12 24 32.5 24.5 

3 N N 34 36 14.5 43 34.5 33 

4 N 0 15.5 7 9 14 8 17 

5b Q D” 43 41 34 47 46 39 

Sum of 

Rank for lines 1 to 4 rankscJ 

l-l 0 0 3 3 4 2 3 4 19 

2-l 0 N 1 2 2 3 2 2 12 

3-l N N 2 1 1 1 1 1 7” 

4-l N 0 4 4 3 4 4 3 22’ 

Sum of 

Rank for lines 1 to 5 ranksf 

-____ ..-.____ --- 

1-2 0 0 4 4 5 3 4 5 25 

2-2 0 N 2 3 3 4 3 3 18 

3-2 N N 3 2 2 2 2 2 13’ 

4-2 N 0 5 5 4 5 5 4 28’ 

5-2 Q D 1 1 1 1 1 1 6” 

Signed rank test comparisons 

l-us. 2 00 vs. ON 

1’~s. 3 00 vs. NN 

1 vs. 4 00 vs. NO 

2 vs. 3 ON vs. NN 

2 vs. 4 ON us. NO 

3 vs. 4 NN vs. NO 

3 vs. 5 NN vs. QD 

Mean values 

compared where : 

Sum of signedg 

First > second First c second ~ o~~.~s limit for 

(+) t-1 Tie + ranks -ranks smaller sum 

1 5 0 1” 20 2 

0 6 0 0’ 21 2 

4 2 0 16 5 2 

1 5 0 1’ 20 2 

6 0 0 21 0’ 2 

6 0 0 21 0’ 2 

0 6 0 0’ 21 2 

0 or N applied 3 3 0 9 12 2 

0 or N read 0 6 0 0’ 21 2 

a 0 designates an independent observer, N an investigator from laboratory 12, Q the previous 

investigator who applied materials, and D the previous reader from this laboratory. 

b Previous results from laboratory 12. 

c ao.05 = 8 to 22. 

d Rank of 1 given to most severe reading; therefore, smaller sum of ranks is more severe than larger. 

;P < 0.05. 

ccO.OS = 9 to 27. 

g Larger sum of signed ranks indicates more severe reading than smaller sum. 
INTERLABORATORY EYE AND SKIN COMPARISONS 349 

In the lines 1 to 5 comparisons (lines l-2 to 5-2), the same trends were present but 

here the previous results (QD) were the most severe, NN being significantly the next 

most severe, and NO significantly least severe, and similar to 00. 

In the signed rank comparisons, many statistically significant differences were seen. 

00 vs. ON-N read more severely 

00 vs. NN-NN results more severe than 00 

ON vs. NN-N read more severely when he applied the materials than when 0 

applied 

ON vs. NO-N read more severely when 0 applied than 0 read when N applied 

NN vs. NO-N applied, but N read more severely than 0 

NN vs. QD-previous results more severe than retest 

Overall, although N did not grade as severely as QD had done previously, he definitely 

graded more severely than did 0, the independent observer. This grading was primarily 

the result of reading the results more severely than 0, not of differences in technique. 

0 observed that N followed the protocol precisely. 

4. Skin test-Laboratory 12. The primary irritation scores and their comparisons are 

presented in Table 66. Note here, as in the eye retest in laboratory 12, a different technician applied and read the skin test results in the retest than in the previous test in this 

laboratory. 

The only significant finding on comparison of sum of ranks was that the previous 

results, QQ, were different from all of the retest ones-for 7 of the 8 chemicals QQ obtained ranks of I-most severe. Note particularly PI scores of 18.5 vs. 4.0 for material 

F; 11.2 US. 0.67 for material M ; 2.0 vs. 0.0 for material I, and 3.2 vs. 0.0 for material N for 

previous results vs. current (retest) results, respectively. 

In the signed rank comparisons, the following were noted: 

00 vs. OF-F tended to read more severely than 0 when 0 applied 

00 vs. FF-FF results were more severe than 00 

OF US. FF-F had more severe readings when he applied than when 0 applied 

FF vs. FO-F read more severely than 0 on rabbits treated by F 

FF vs. QQ-previous laboratory 12 test results were more severe than in retest 

In the overall reading, F definitely read more severely than 0. 0 observed that F 

followed the protocol precisely. 

5. Intercomparisons of retest and previous test scores. Table 67 presents the eye and 

skin test scores for the retest and previous test results in laboratories 27 and 12, as well 

as the scores for 0 in both laboratories during these retests. On the eye test, 0 consistently read higher, more severely, in laboratory 27 than he did in laboratory 12 (columns 

1 vs. 2). The same tendency was present, although here not statistically significant, for 0 

for the skin test (7 US. 8). Contrariwise, N in laboratory 12 had more severe readings 

than did R in laboratory 27 for the eye (columns 3 vs. 4) and skin (columns 7 vs. 10) tests. 

Thus, 0 in laboratory 27 had higher scores than in laboratory 12, but R in laboratory 27 

had lower scores than N in laboratory 12-both being retest results. In previous testing, 

laboratory 27 was consistently less severe than laboratory 12 on both eye and skin tests 

(columns 5 US. 6 and 11 vs. 12). Therefore, while the previous trend of less severe results 
350 WEIL AND SCALA 

TABLE 66 

SCORESAND COMPARISONSOFREFERENCE SKINPROCEDUREIN LABORATORY 12 

WHERE TWOTECHNICIANSAPPLIEDAND/ORREAD RESULTS 

Applied Read 

Primary irritation score for material 

Line by 

1 

2 

3 

4 

9 

1-l 

2-1 

3-l 

4-l 

l-2 

2-2 

3-2 

4-2 

5-2 

--~ 

0” 

0 

F 

F 

Q 

0 

0 

F 

F 

0 

0 

F 

G 

by E F I J K L M N 

0 0.33 -1.17 0.50 1.50 1.33 5.50 1.17 0.17 

F” 0.50 1.00 0.67 1.83 2.00 14.70 1.17 0.00 

F 2.17 4.00 0.00 2.83 3.50 15.00 0.67 0.00 

0 1.00 1.00 0.33 2.50 2.50 5.00 0.67 0.00 

Q 1.1 18.5 2.0 4.2 5.2 22.6 11.2 3.2 

Sum of 

Rank for lines 1 to 4 ranksEed 

04 22 4 4 3 1.5 1 21.5 

F 3 3.5 1 3 3 2 1.5 3 20.0 

F 1 1 4 1 

0 2 3.5 3 2 : 

1 3.5 3 15.5 

4 3.5 3 23.0 

Sum of 

Rank for lines 1 to 5 rankse 

-~~ 

05 33 5 5 4 2.5 2 29.5 

F 4 4.5 2 4 4 3 2.5 4 28.0 

F 1 2 5 2 2 2 4.5 4 22.5 

3 4.5 4 3 3 5 4.5 4 

:21111 111 

31.0 

9.0s 

Signed rank test comparisons 

Sum of signedg 

First > second First c second c(0,05 limit for 

(+I (-) Tie + ranks - ranks smaller sum 

1 vs. 2 00 vs. OF 

1 vs. 3 00 vs. FF 

1 vs. 4 00 vs. FO 

2 vs. 3 OF vs. FF 

2 vs. 4 OF vs. FO 

3 vs. 4 FF vs. FO 

3 vs. 5 FF vs. QQ 

Mean values 

compared where: 

1 5 23 

0 6s 30 

0 15 21 

1 5 23 

2 10 11 

2 19.5 1.5f 

0 1’ 35 

0 or F applied 4 4 0 10 26 6 

0 or F read 2 5 1 3f 25 4 

’ 0 designates an independent observer, F an investigator from laboratory 12, Q the previous 

investigator from this laboratory. 

* Previous results from laboratory 12. P c(,,.05 = 12 to 28. 

d Rank of 1 given to most severe reading; therefore, smaller sum of ranks is more severe than larger. 

e Q.05 = 13 to 35. 

f P < 0.05. 

g Larger sum of signed ranks indicates more severe reading than smaller sum. 
INTERCOMPARISONS OF RETEST AND TEST SCORES IN Two LABORATORIES 

Applied and read by” 

Applied and Applied and 

read by 0” R N R Q>D read by 0” 

Eye test-24-hour median score Skin test-primary 

-- 

Retest First test Ret

Lab. Lab. Lab. Lab. Lab. Lab. Lab. Lab. 

Material 21 12 27 12 27 12 Material 27 12 

Column 

1 2 3 4 5 6 7 8 

.-~. 

F 29 16 18 34 24 43 E 0.17 0.33 

J 18 14.5 21.5 36 9.5 41 F 1.67 1.17 

K 15.5 8 24 14.5 4 34 I 1.17 0.50 

L 25.5 24.5 20 43 20 47 J 1.83 1.50 

M 33.5 18 24.5 34.5 24 46 K 2.17 1.33 

N 43 11 16.5 33 2 39 L 5.50 5.50 

M 0.67 1.17 

N 0.00 0.17 

Signed rank test comparisons 

Sum of signed 

Columns First > second First x second 

No. (+I C-1 Tie + ranks - ranks 

1 vs. 2 6 0 0 21 Ob 

3 vs. 4 1 5 0 ;: 20 

5 vs. 6 0 6 0 21 

7 vs. 8 4 3 1 20.5 7.5 

9 vs. 10 4 4 0 13.5 22.5 

11 vs. 12 0 8 0 Ob 36 

d See Tables 63-66 for definitions of 0, R, N, Q, D, and F. 

b P < 0.05. 
352 WEIL AND SCALA 

in laboratory 27 than in laboratory 12 was duplicated in the retest results with the previous and current technicians in these laboratories (different ones for laboratory 12 for 

the rerun than for the previous test), the independent observer, 0, had the opposite 

trend. It is therefore concluded that the major differences between these two laboratories-which scored at the opposite extremes in the previous tests-could not have been 

primarily produced by differences in the stocks of rabbits used, but was largely the 

result of different grading by the technicians. It is noteworthy that the trained observer, 

0, obtained different readings in different laboratories with these tests. Furthermore, 

the tendency in each laboratory in the retest to read more like the average laboratory and 

less extremely than in the first runs, might have been the result of more careful interpretation of the protocol and definitions involved when the technicians knew they were to 

be observed by an independent technician. 

DISCUSSION AND CONCLUSIONS 

The tests currently used by most laboratories for rating materials for the degree of 

eye or skin irritation are the same as or minor modifications of the Draize, or FHSA, 

procedure. The reference procedures, used by 24 laboratories for the eye and by 22 for 

the skin tests, were also quite similar to the above. 

It was clearly demonstrated that several laboratories were outliers. They consistently 

read either more severely or less severely than most other laboratories. Thus, the tests 

which have been used for over 20 years to decide the degree of eye or skin irritation produce quite variable results among the various laboratories as well as within certain 

laboratories. To use these tests, or minor variations of them, to obtain consistency in 

classifying a material as an eye or skin irritant or nonirritant, therefore, is not deemed 

practical. All the collaborative tests were performed with aliquots of reference samples. 

Considerably more variation would be expected if independently produced samples 

had been used. 

The extreme variation between laboratories cannot be entirely explained by any one 

of the many factors involved. In most cases, judged by the retest performed in 2 of the 

laboratories, the primary reason for differences was in the reading of reactions, as 

opposed to variation in interpretation of and performance of the procedures. The latter, 

however, was also a component of the interlaboratory variability. 

The variability in total eye injury scores or in average primary skin irritation scores 

was also present, as might have been expected, in the reading of the components of these 

scores. Thus, the words used to describe injury of the conjunctiva, the iris, or the lid of 

the eye or to describe erythema, edema, or necrosis of the skin are interpreted differently 

by many different laboratories. A change in the “standard” procedures currently used, 

or in the descriptions or definitions of the degrees of injury, would probably not suffice. 

The most efficient way to have less variability between laboratories, i.e., between individual technicians, would probably be to conduct courses or clinics in methodology. 

These would have to be repeated at frequent intervals to accommodate new technicians 

or new toxicologists. In the meantime, it is suggested that the rabbit eye and skin procedures currently recommended by the Federal agencies for use in delineation of irritancy of materials should not be recommended as standard procedures in any new 

regulations. Without careful reeducation these tests result in unreliable results. 
INTERLABORATORY EYE AND SKIN COMPARISONS 353 

The outlying laboratories, those which read consistently high or low, were distributed practically equally between the consultant, the toilet goods or cosmetic, the food 

or industrial chemical, and the governmental laboratories that took part in this 

collaborative test. Therefore, the suggestion that any one type of laboratory do all of 

the irritation testing is as impractical as the suggestion that any one type of laboratory 

do any of the toxicity tests, e.g., for chronic injury, for carcinogenicity, for teratology, 

for mutagenicity, etc. Unconscious bias or definite tendencies to over- or underread 

reactions or misinterpret the meaning of descriptive terms can be counteracted only by 

having several or many laboratories perform similar tests. It is obvious that this is not 

the time to recommend any standard or reference procedure in this or in most of the 

other phases of degree of hazard testing. The more varied the approach to this, the 

sooner better techniques can be developed which might lead to more uniform results. 

SUMMARY 

1. In testing reference samples by the reference eye or skin irritation procedures, most 

laboratories rated relatively nonirritating materials similarly. These materials were 

eliminated from most of the inter- and intralaboratory comparisons to prevent fictitious 

correlations. 

2. The range in eye or skin irritation scores between individual rabbits was relatively 

large in some laboratories and small in others. 

3. Eye healing with most materials was noted in most laboratories during the 7-day 

observation period; in others the injuries progressed. 

4. The scores for the components of the total score for the eye test (for the injury to 

the cornea, iris, and conjunctivae) also varied considerably among the individual 

rabbits treated and among the 24 laboratories that used the reference procedure. Similarly, the degree of erythema, edema, and necrosis reported on the skin test by 22 laboratories for the 10 materials tested in the reference procedure varied from no reaction to 

severe irritation and tissue damage. 

5. Certain laboratories consistently recorded unusually severe scores (indicated by 

sum of ranks) for the materials tested in the reference eye and/or skin procedures; other 

laboratories reported consistently nonirritating scores (interlaboratory comparison). 

6. Certain materials were rated as the most irritating tested by some laboratories 

and, contrariwise, as the least irritating by others. 

7. The variability (indicated by semi-interquartile range) among the interlaboratory 

ranking was small for some and large for other laboratories. Thus, some laboratories 

varied considerably in relative rating of materials, others generally tended to rate most 

materials more severely than other laboratories, and still others consistently rated 

materials nonirritating. 

8. Generally, the reading of relatively severe eye or skin reactions in particular 

laboratories was correlated with low variability on readings among individual rabbits. 

9. The relative interlaboratory position for severity of or variability among reactions 

recorded was unrelated to the type of laboratory. Some outliers were consultant, some 

toilet goods or cosmetic, some food or industrial chemical, and some were government 

laboratories. 
354 WEIL AND SCALA 

10. More agreement on the relative ranking of the irritation potential of the samples 

was found among the laboratories (intralaboratory comparison) than on the relative 

ranking of the laboratories by their readings of the irritancy of the samples (interlaboratory comparison). Nevertheless, many laboratories lacked significant correlation 

in intralaboratory sample ranking compared with the overall laboratory sample ranks. 

11. More laboratories (10 of 16) lacked significant correlation between reference and 

nonreference procedures on the eye than on the skin tests (3 of 19 laboratories). This 

was true for the eye test in many cases when the reference and non-reference procedures 

were almost, or completely, identical. 

12. The all-or-none, irritant or nonirritant, eye or skin rating of the reference samples 

was determined quite differently in different laboratories. 

13. There was a tendency for a significant correlation between the severity of scoring 

eye and of skin reactions in most of the laboratories. However, some laboratories 

differed considerably in this. 

14. In a retest of two outlying laboratories, the technicians tended to read in the same 

direction as before, but less extremely, while an independent observer who applied and 

read materials in both laboratories had the opposite tendency, i.e., he read less severely 

in the laboratory which, generally, read more severe reactions than most others, and 

vice versa. 

ACKNOWLEDGMENTS 

The authors wish to thank the Collaborative Study Steering Committee for their assistance 

in the design of the procedures. We are also deeply appreciative of the time and effort expended 

by the personnel in each of the laboratories that participated and of the publication support 

supplied by Esso Research and Engineering Company, Linden, New Jersey. 

Cited in Test 

REFERENCES 

21 Code of Federal Regulations 191.1 (g) (2) (3). 

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ROUDABUSH, R. L., TERHAAR, C. J., FASSETT, D. W., and DZIUBA, S. P. (1965). Comparative 

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SNEDECOR, G. W., and COCHRAN, W. G. (1967). StatisticalMethods, 6th ed., pp. 195-196,557. 

Iowa State Univ. Press, Ames, Iowa. 

THOMPSON, W. A., JR., and WILLKE, T. A. (1963). On an extreme rank sum test for outliers. 

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WEIL, C. S., and WRIGHT, G. J. (1967). Intra- and interlaboratory comparative evaluation of 

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WILCOXON, F., KAY, S. K., and WILCOX, R. A. (1963). Critical values andprobability levels 

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Other 

Skin and Eye Irritation 

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INTERLABORATORY EYE AND SKIN COMPARISONS 355 

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LEHMAN, A. J., and DRAIZE, J. H. (1959). Dermal and eye mucosa tolerances for certain surfaceactive agents. Ass. Food Drug OfJic. U.S. Quart. Bull. 23, 150-152. 

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141-146. 

RIEGER, M. M., and BATTISTA, G. W. (1964). Some experiences in the safety testing of cosmetics. 

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356 WEIL AND SCALA 

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INTERLABORATORY EYE AND SKIN COMPARISONS 351 

APPENDIX 

Scale for Scoring Ocular Lesions* 

(1) Cornea 

(A) Opacity-degree of density (area most dense taken for reading) 

No opacity . . . . . . . 

Scattered or diffuse area, details bf iris clearly visible . . . . 

Easily discernible translucent areas, details of iris slightly obscured . . 

Opalescent areas, no details of iris visible, size of pupil barely discernible . 

Opaque, iris invisible 

. 0 

. 1 

. 2 

. 3 

(B) Area of cornea involved ’ ’ ’ ’ ’ ’ ’ ’ ’ ’ 

4 

One quarter (or less) but not zero . 1 

Greater than one quarter, but less than half : : : : : : : 2 

Greater than half, but less than three quarters . . . . . . 3 

Greater than threequarters, up to wholearea . . . . . . . 4 

Score equals A x B x 5 Total maximum = 80 

(2) Iris 

(A) Values 

Normal . . . . . 

Folds above normal, congestion, swelling 

. . 

circumcorneal injection (any or all of 

0 

these or combination of any thereof) i;is still reacting to light (sluggish reaction is positive) . . . . 

No reaction to light, hemorrhage,‘gross destruction (any or all’of these) : 

. 1 

. 2 

Score equals A x 5 Total maximum = 10 

(3) Conjunctivae 

(A) Redness (refers to palpebral and bulbar conjunctivae excluding cornea and iris) . 0 

Vessels normal . . . . . . . . . . 0 

Vessels definitely injected above normal . . . . . . 1 

More diffuse, deeper crimson red, individual vessels not easily discernible . . 2 

Diffuse beefy red . . . . . . . . . . . 3 

(B) Chemosis 

No swelling . . . . . . . . . . . . 0 

Any swelling above normal (includes nictitating membrane) . . . . 1 

Obvious swelling with partialeversion oflids . . . . . . . 2 

Swelling with lids about half closed . . . 

Swelling with lids about half closed to completely closed : 

. . . . 3 

. . . . 4 

(C) Discharge 

No discharge . . . . . . . . . . . 0 

Any amount different from normal (does not include small amounts observed in 

inner canthus of normal animals) . . . . . . . , 1 

Discharge with moistening of the lids and hairs just adjacent to lids . . . 2 

Discharge with moistening of the lids and hairs, and considerable area around 

the eye 

Score equals (A + B i C’) i 2 ’ ’ ’ ’ ’ ’ ‘Total’maximum 12: 

The maximum total score is the sum of all scores obtained for the cornea, iris, and conjunctivae. Total maximum score possible = 110. 

* Draize et al. (1944). 
A.?. DATA SHEET 

Rabbit E),e Irritatiorl Scores Refretlce Procedure 

Sample: 

1 Hour 24 Hours 

Laboratory: 

Date of Application: 

71 Hours 

I. Cornea 

B. Area involved 

B. Chemosis 

Applied by : 

Graded by: 

Round Robin Program for Eye and Skin Irritants 
INTERLABORATORY EYE AND SKIN COMPARISONS 359 

B. 1. Scoring and Evaluation-Reference Skin Test 

The parameters of (1) Erythema, (2) Edema, and (3) Necrosis will be evaluated for each 

chemical on all animals using the following scoring system: 

(1) Erythema 

No erythema 0 

Very slight erythema (barely perceptible) 1 

Well-defined erythema 2 

Moderate to severe erythema 3 

Severe erythema (beet redness) 4 

Total possible erythema score per animal for combined 24- and 72-hour reading 8 

(2) Edema 

No edema 0 

Very slight edema (barely perceptible) 1 

Slight edema (edges of area well defined by definite raising) 2 

Moderate edema (raising approx. 1 mm) 3 

Severe edema (raising more than 1 mm and extending beyond area of exposure 4 

- 

Total possible edema score per animal for both 24- and 72-hour reading 8 

(3) Necrosis* 

No necrosis 0 

Slight necrosis (less than a of exposed area) 5 

Moderate necrosis (+ to 3 of exposed area) 10 

Severe necrosis (more than 3 of exposed area) 15 

Total possible score for both 24- and 72-hour reading 30 

* Necrosis for the purpose of this scoring system is defined as a chemical denaturation of tissue 

sufficiently severe to result in fibrotic replacement (scar tissue). Superficial eschar which heals without 

scar is not classified as necrosis. 
B.2. DATA SHEET 

Rabbit Primary S’kin Irritation Scores--Reference Method 

Sample: 

Laboratory: 

Date of App

Total score 

Sum of tota

Applied by: 

Graded by: 

Round Robin Program for Eye and Skin Irritants