A specimen-collection wipe 2 is suitable for use in testing for the presence of occult blood in fecal matter or other bodily substance. The wipe 2 includes a substrate 4 having a hand-contact surface 11 for manipulating the wipe 2 and an occult-blood detection-test surface 10 for collecting a specimen and supporting it during treatment with an occult-blood indicator fluid. The substrate 4 has a sufficiently low wet strength to permit the wipe 2 to be disposed of in a toilet and preferably has a sufficiently high resistance to seepage to permit the hand-contact surface 11 to remain dry for the duration of the test. The wipe 2 also includes an indicator-activity verification region 14 on which is dispersed a reagent capable of interacting with the occult-blood indicator fluid to provide an indication characteristic of the presence of occult blood.

TECHNICAL FIELD 
The present invention relates to a disposable wipe for use in collecting 
specimens of fecal matter or other bodily substance and testing the 
specimens for the presence of occult blood. 
BACKGROUND ART 
The presence of blood in feces can signal the existence of a tumor, ulcer, 
or other medical disorder along the digestive tract. In early stages of 
development, a tumor or ulcer on the digestive tract may bleed to such a 
slight extent that the blood, while present in the feces, is not visible. 
Nonetheless, in such cases, the blood, termed "hidden" or "occult" blood, 
can usually be detected with one of a number of indicator reagents which 
change color in the presence of the hemoglobin in blood. 
One of the most widely used occult-blood indicator reagents is derived from 
an extract from the wood of certain species of trees of the Guaiacum genus 
native to the American tropics. The extract, termed guaiac, turns from 
essentially colorless to blue in the presence of hemoglobin and an 
oxidizing agent such as hydrogen peroxide. More specifically, the guaiac 
reagent is sensitive to what is termed "peroxidase activity" which results 
from the combination of an oxidizing agent with hemoglobin or certain 
chemically similar compounds. 
Testing feces for the presence of occult blood with an occult-blood 
indicator reagent is a valuable medical diagnostic tool, since such 
testing can often detect tumors in the digestive tract at an early stage 
of their development, typically before the tumors manifest other symptoms 
and at a stage when they can be treated most successfully. 
A procedure widely used by physicians and medical laboratories for testing 
for occult blood in fecal matter makes use of a test slide of the type 
disclosed in U.S. Pat. No. 4,365,970 to Lawrence and Townsley. The test 
slide of the Lawrence and Townsley patent includes a sheet of 
guaiac-impregnated indicator paper enclosed in a cardboard envelope. A 
front panel of the envelope has openings in it for smearing samples of 
fecal matter on a first side of the indicator paper. A rear panel of the 
envelope has an opening for applying a hydrogen peroxide developing 
solution to a second side of the indicator paper. A blue stain on the 
indicator paper signifies the presence of occult blood in the sample of 
fecal matter on the opposite side. Since the blue stain appears on the 
side of the indicator paper opposite to the samples of fecal matter, the 
developing solution necessarily soaks through the paper in the test 
procedure. The indicator sheet of the test slide of the Lawrence and 
Townsley patent has a control area designated on its second side which 
includes a positive monitor and a negative monitor. Hemin, a 
hemoglobin-derived compound, is printed on the positive monitor, but not 
on the negative monitor. Application of the developing solution to the 
control area causes the indicator paper to turn blue at the positive 
monitor and remain colorless at the negative monitor if the test reagents 
are properly active and if the test slide has not been contaminated with a 
compound which yields a false indication of the presence of hemoglobin. 
Although the test slide of the Lawrence and Townsley patent is generally 
satisfactory for use in a doctor's office or a hospital, it has 
significant disadvantages for home use. An applicator stick must be used 
to collect each sample of fecal matter from a toilet bowl and to smear the 
sample on the test slide. The person using the test slide thus has the 
problem of disposing of the applicator sticks and, after applying the 
developing solution to the slide, disposing of the test slide itself. 
Neither the applicator sticks nor the test slide can be flushed down the 
toilet. Even if the test slide is forwarded to a doctor's office or 
medical laboratory for analysis, the problem of disposing of the soiled 
applicator sticks remains for the user. 
U.S. Pat. No. 4,175,923 to Friend discloses a test for the presence of 
occult blood in fecal matter which is intended to be carried out at home. 
The test makes use of an indicator paper prepared by impregnating a sheet 
of absorbent paper with guaiac reagent. A portion of the indicator paper 
is also impregnated with blood. The test of the Friend patent involves 
applying a developing solution to a sheet of the indicator paper and then 
tossing the sheet into a toilet bowl to contact the paper with the water 
in the bowl. The developing solution causes the portion of the indicator 
paper impregnated with blood to turn blue if the guaiac reagent and 
developing solution are properly active. If stools in the toilet bowl 
contain occult blood, blood will disperse in the water in the bowl. Blood 
in the water in the toilet bowl will in turn cause the remainder of the 
indicator paper to turn blue. After allowing time for the color of the 
indicator paper to change, the paper can be flushed down the toilet with 
the stools. 
Although the occult-blood detection test of the Friend patent is 
satisfactory in principle, it is limited in a number of respects. 
Ordinarily, for occult blood in fecal matter to be detected by the test, 
the blood must disperse in the water of the toilet bowl. Such dispersal 
necessarily dilutes the blood and thus reduces the sensitivity of the 
test. In addition, the test results may be suspect as a consequence of the 
presence of contaminants in the toilet bowl. Furthermore, guaiac reagent 
is subject to degradation by oxygen in the air. Consequently, the sheets 
of indicator paper are preferably stored individually in sealed foil 
envelopes or air-tight packages of some other sort to increase shelf-life 
stability. Such air-tight packaging increases the cost of the test to the 
user. 
DISCLOSURE OF THE INVENTION 
We have invented a convenient disposable specimen-collection wipe for use 
in an occult-blood detection test suitable for carrying out at home which 
avoids problems of the prior art noted above. The specimen-collection wipe 
is especially suited for use in connection with a method and composition 
for detecting peroxidase activity disclosed in U.S. patent application 
Ser. No. 471,372, filed Mar. 1, 1983 (the '372 application) and assigned 
to the assignee of the present application. The specification of the '372 
application is hereby incorporated by reference in the present 
application. 
Broadly, the specimen collection wipe of the present invention comprises a 
substrate having a hand contact surface for manipulating the wipe and an 
occult-blood detection-test surface. Two regions are defined on the 
detection-test surface: (1) a specimen-collection region for collecting a 
specimen of fecal matter or other bodily substance and for supporting the 
specimen during application of an indicator fluid such as one of the 
self-developing indicator solutions disclosed in the '372 application 
cited above, and (2) an indicator-activity verification region for testing 
the activity of the indicator fluid. The substrate is guaiac free and 
constructed of a pliable material such as multiple-ply tissue paper. The 
substrate has a sufficiently low wet strength to permit the wipe to be 
flushed down a toilet. In addition, the substrate preferably has a 
sufficiently high resistance to seepage by the indicator fluid from the 
detection-test surface to the hand-contact surface to permit the 
hand-contact surface to remain dry for the duration of an occult-blood 
detection test. 
The wipe of the invention incorporates an indicator-activity test reagent 
in the indicator-activity verification region of the detection-test 
surface of the substrate. The indicator-activity test reagent is capable 
of interacting with the indicator fluid to provide an indication 
characteristic of the presence of occult blood. Thus, if a dose of a 
self-developing-guaiac indicator solution of the '372 application is 
sprayed on the indicator-activity verification region of a wipe of the 
invention, the indicator fluid ordinarily turns from essentially colorless 
to blue. Failure of the indicator fluid to change color is a signal that 
the indicator fluid may be inactive for some reason and that any negative 
result of the occult-blood detection test should be suspect. 
The wipe is of a size and shape to be manipulated by hand and therefore a 
wide range of sizes and shapes are usable. In a preferred embodiment of 
the invention, the wipe is in the form of a generally rectangular pad from 
about 80 mm to about 150 mm wide and from about 100 mm to about 200 mm 
long. Dimensions of roughly 100 mm wide by roughly 150 mm long are 
particularly preferred. Alternatively, the wipe could be circular or oval 
in shape. The wipe could also be fabricated as a mitt to be worn over the 
hand. It will be recognized that the wipe of the invention could be 
fabricated in other forms and sizes. 
In a preferred embodiment of the invention, the substrate is a generally 
rectangular pad formed from a number of sheets of absorbent, porous, soft, 
low-wet-strength paper of the type used as toilet tissue. The sheets are 
arranged one on top of the other. For example, a pad composed of nine 
plies of tissue paper has served successfully as a substrate for a wipe of 
the invention. However, either a greater or lesser number of plies may be 
advantageous in certain applications, depending, for example, on the 
weight and stiffness of the individual plies of tissue paper. 
In an embodiment in which the substrate is a pad formed from plies of 
tissue paper, the plies are preferably joined together around their 
periphery. The plies may be joined by crimping. Crimping the plies 
together around the periphery of the pad permits the plies to separate 
from one another readily when the wipe is soaked with water. Consequently, 
the wipe may be safely disposed of in a toilet. Furthermore, a pad formed 
from plies of tissue paper crimped together is economical to manufacture. 
Alternatively, the plies of tissue paper may be joined with an adhesive, 
preferably applied around the periphery of the pad. The adhesive is 
preferably water soluble or otherwise water degradable to permit the wipe 
to be disposed of readily in a toilet. 
The wipe of the invention is preferably biodegradable. 
The substrate of the wipe of the invention should not include any 
contaminant in the specimen-collection region which would give rise to a 
false indication of the presence of occult blood. Commercially available 
grades of tissue paper such as used for toilet tissue generally do not 
include such contaminants. 
For use with a self-developing guaiac indicator solution of the '372 
application, the detection-test surface of a wipe of the invention is 
advantageously white or yellow in color to provide a visual contrast with 
the indicator fluid, which turns blue on contact with occult blood. To 
less advantage, the surface may also be colored pink. A green or blue 
color for the detection-test surface in this application, while possible, 
is generally not preferred, since a blue or green background tends to mask 
the color change provided by the guaiac indicator solution. 
The indicator-activity test reagent preferably includes hematin, a 
derivative of hemoglobin with the following systematic name: 
[7,12-Diethenyl-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoato(2 
-)-N.sup.21,N.sup.22,N.sup.23,N.sup.24 ]-hydroxyiron. Hematin may be 
applied to the indicator-activity verification region as a basic solution 
in a mixture of ethanol and water. Any reagent exhibiting peroxidase-like 
activity; such as hemin, hemoglobin, or whole blood (either human blood or 
animal blood); may be used as an indicator-activity test reagent if 
desired since such reagents provide a reaction with indicator fluids 
characteristic of occult blood. 
The indicator-activity verification region is preferably substantially 
smaller in area than the specimen collection region and is preferably 
clearly marked on the detection-test surface of the wipe of the invention. 
The shape of the indicator-activity verification region is not critical. 
The verification region, for example, may be generally circular, 
rectangular, or of another shape. More than one indicator-activity 
verification region may be included if desired. A corresponding region 
which includes no indicator-activity test reagent may be marked on the 
detection-test surface as well to serve as a neutral-response region. Ink 
used for marking the various regions on the detection-test surface should 
be safe for human contact and should not give rise to a false indication 
of the presence of occult blood or otherwise distort the results of the 
test. 
Preferably, the substrate of a wipe of the invention retards the seepage of 
indicator fluid from the detection-test surface of the wipe to the 
hand-contact surface for at least 30 seconds to give the user time to hold 
the wipe in his hand and observe the test results before dampness is 
detected on the hand-contact surface. The hand-contact surface of a 
preferred wipe of the invention made up of nine plies of tissue paper 
generally remains dry to the touch indefinitely after a standard 
occult-blood detection-test dose of roughly 0.9 ml of a self-developing 
indicator solution of Example I the '372 application is applied to the 
detection-test surface on the opposite side of the wipe. Although it is 
possible to soak such a wipe through in less than 30 seconds by applying 
three times the standard test dose of indicator solution, when the 
standard test dose is applied, the indicator solution generally evaporates 
to dryness from the detection-test surface before it can penetrate to the 
hand-contact surface of the wipe. 
It is believed that the remarkable resistance to seepage from front to back 
in a pad of plies of tissue paper joined at their periphery is a result of 
the light contact the various plies make with one another in the central 
region of the pad. Fluid tends to flow by capillary action laterally 
within a sheet of tissue paper far more readily than it tends to flow from 
one sheet of tissue paper to the next. Moreover, the first four or five 
plies or so of the nine plies of tissue paper in preferred wipes of the 
invention have sufficient fluid-holding capacity to absorb all of the 
indicator fluid applied to the wipe in a typical occult-blood detection 
test. 
Although in principle a moisture-impermeable polymer film could be 
incorporated in the wipe of the invention to serve as a moisture barrier, 
conventional polymer films typically have too great a wet strength to be 
readily disposable in a toilet.

BEST MODE FOR CARRYING OUT THE INVENTION 
Turning now to FIG. 1, a specimen-collection wipe 2 includes a pad 4. As 
shown in FIG. 2, the pad 4 is made up of nine plies of tissue paper 6 
arranged one on top of the other. The plies of tissue paper 6 are crimped 
together around the periphery 8 of the pad 4. A first side 10 of the pad 4 
defines an occult-blood detection test surface for the wipe and a second 
side 11 defines a hand-contact surface. Printed on the detection-test 
surface 10 are designations of three regions: a specimen collection region 
12, a indicator-activity verification region 14 and a neutral-response 
region 16. The indicator-activity verification region 14 is denoted 
"Positive" and the neutral-response region 16 is denoted "Negative." A 
hematin reagent is absorbed in the indicator-activity verification region 
14. 
The hematin reagent is deposited within the indicator-activity verification 
region 14 by moistening the region 14 with a hematin solution, then 
allowing the solvent to evaporate from the moistened area to leave behind 
a deposit of hematin reagent. The hematin solution is prepared as follows: 
Water and ethanol are mixed in the proportion of about 25 percent by 
volume water and about 75 percent by volume ethanol. Sodium hydroxide is 
added to the water/ethanol mixture in an amount sufficient to form a 
solution of about 0.01 molar sodium hydroxide. To this basic water/ethanol 
solution is added a quantity of hematin sufficient to yield a solution 
containing about 6 mg of hematin per liter of solution. 
The self-developing indicator solution of Example II, Run 2 of the '372 
application is suitable for use with the wipe 2. This indicator solution 
may be prepared as follows: To a flask is added about 100 ml of ethanol 
followed by addition of about 1 gram of guaiac powder. The contents are 
mixed for approximately 30 minutes to dissolve the guaiac indicator in the 
ethanol solvent. The solution is filtered to remove undissolved particles. 
About fifty (50) ml of the resulting solution is mixed with approximately 
4.5 ml of about 30 percent hydrogen peroxide, followed by the addition of 
about 15 ml of approximately 0.1 molar citrate buffer to adjust the pH to 
about 5.0. Approximately ten (10) ml of water are added to prevent 
crystallization of the buffer. Fresh ethanol is then added to increase the 
volume to about 100 ml. The resulting solution exhibits a slight amber 
color. 
The wipe 2 in conjunction with the self-developing indicator solution of 
the preceding paragraph can be used as follows to test for the presence of 
occult blood in fecal matter. The user first obtains a sample of fecal 
matter by defecating. A specimen of the fecal matter is collected on the 
specimen-collection region 12 of the wipe 2 by contacting the region 12 
the wipe 2 with the fecal matter while defecating or by patting in the 
anal area with the region 12 of the wipe 2. The user then applies a dose 
of the occult-blood indicator solution from a spray applicator to the 
specimen of fecal matter on the wipe. Typically, three squirts are 
applied, with each squirt of the applicator delivering roughly 0.18 ml of 
solution. In addition, single-squirt doses of indicator solution are 
applied respectively to the indicator-activity verification region 14 and 
to the neutral-response region 16 of the wipe. If the indicator solution 
is properly active, the solution will change color in the 
indicator-activity verification region 14. If the wipe has not been 
contaminated with a substance which gives a false indication of occult 
blood, the indicator solution will remain essentially colorless in the 
neutral response region 16. Thus, if the indicator solution either fails 
to turn blue in the indicator-activity verification region 14 or turns 
blue in the neutral response region 16, the results of the test are 
suspect. If the indicator solution which contacts the specimen of fecal 
matter does not change color, the specimen probably contains at most an 
insignificant quantity of occult blood. If, on the other hand, the 
indicator solution which contacts the specimen turns blue, the presence of 
occult blood is indicated and the user should consult a physician. After 
the test is completed the user can toss the wipe into the toilet bowl and 
flush it away. 
It is not intended to limit the present invention to the specific 
embodiments described above. For example, the substrate of the wipe of the 
invention may be made of flushable felt, wadding, sponge or fabric, if 
desired. A pad suitable for a wipe of the invention may be made from 
sheets of creped, low-wet-strength tissue. The wipe may be folded so that 
the indicator-activity verification region and neutral-response region 
generally face away from the specimen-collection region to prevent the 
indicator-activity verification and neutral-response regions from becoming 
soiled with fecal matter during the collection of a specimen. After 
collection of the specimen, the wipe can be unfolded to permit the 
indicator fluid to be applied conveniently to all three regions. The 
indicator-activity verification region and neutral-response region may be 
covered with a removable, flushable paper strip or other suitable barrier 
to soiling if desired. The wipe of the invention may be used with 
indicator fluids other than those disclosed in the '372 application and 
may be used to detect occult blood in bodily substances other than fecal 
matter. It is recognized that these and other changes may be made in the 
invention specifically described herein without departing from the scope 
and teachings of the instant invention and it is intended to encompass all 
other embodiments, alternatives, and modifications consistent with the 
invention.