NISTIR 7880-25 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter and Summer 1999 

Comparability Studies 

Results for Round Robin XLV and XLVI 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 12 Ascorbic Acid in Human Serum 

David L. Duewer 

Sam A Margolis (Retired) 

Katherine E. Sharpless 

Jeanice B. Thomas 

 

 

 

 

 

NISTIR 7880-25
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter and Summer 1999 

Comparability Studies 

Results for Round Robin XLV and XLVI 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 12 Ascorbic Acid in Human Serum 

David L. Duewer 

Sam A Margolis (Retired) 

Katherine E. Sharpless 

Jeanice B. Thomas 

Chemical Sciences Division 

Materials Measurement Laboratory 

June, 2013 

U.S. Department of Commerce 

Penny Pritzker, Secretary 

National Institute of Standards and Technology 

Patrick D. Gallagher, Under Secretary of Commerce for Standards and Technology and Director 
(This page intentionally blank) 

ii
 
 

 

 

 

Abstract 

The National Institute of Standards and Technology coordinates the Micronutrients Measurement 

Quality Assurance Program (MMQAP) for laboratories that measure fat- and water-soluble vitamins 

and carotenoids in human serum and plasma. This report describes the design of and results for the 

Winter and Summer 1999 MMQAP measurement comparability improvement studies: 1) Round 

Robin XLV Fat-Soluble Vitamins and Carotenoids in Human Serum, 2) Round Robin XLVI FatSoluble Vitamins and Carotenoids in Human Serum, and Round Robin 12 Vitamin C in Human 

Serum. The materials for Round Robin XLV were shipped to participants in January 1999; 

participants were requested to provide their measurement results by April 2, 1999. The materials for 

Round Robin XLVI were shipped to participants in June 1999; participants were requested to 

provide their measurement results by September 10, 1999. The sample materials for Round Robin 

12 were distributed in February 1999 with results due by March 26, 1999; a “Final Report” that 

combined results for Round Robins 11 and 12 was distributed in August 1999. 

Keywords 

Human Serum
 

Retinol, α-Tocopherol, γ-Tocopherol, Total and Trans-β-Carotene
 

Ascorbic Acid, SRM 970
 

iii 
 

 

 

 

 

 

 

 

 

 

Table of Contents 

Abstract............................................................................................................................................... iii
 

Keywords ............................................................................................................................................ iii
 

Table of Contents ............................................................................................................................... iv
 

Introduction......................................................................................................................................... 1
 

Round Robin XLV: Fat-Soluble Vitamins and Carotenoids in Human Serum .......................... 1
 

Round Robin XLVI: Fat-Soluble Vitamins and Carotenoids in Human Serum ......................... 2
 

Round Robin 12: Vitamin C in Human Serum............................................................................... 2
 

References ............................................................................................................................................ 3
 

Appendix A. Shipping Package Inserts for RR45........................................................................ A1
 

Appendix B. Final Report for RR45 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR45 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR45 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR46 ......................................................................... E1
 

Appendix F. Final Report for RR46............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR46..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR46............................................... H1
 

Appendix I. Shipping Package Inserts for RR12 ........................................................................... I1
 

Appendix J. Combined Final Report for the RR11 and RR12 ..................................................... J1
 

Appendix K. Representative “Individualized Report” for the Combined RR11 and RR12 ... K1
 

iv 
 

 

 

Introduction 

Beginning in 1988, the National Institute of Standards and Technology (NIST) has coordinated the 

Micronutrients Measurement Quality Assurance Program (MMQAP) for laboratories that measure 

fat- and water-soluble vitamins and carotenoids in human serum and plasma. The MMQAP 

provides participants with measurement comparability assessment through use of interlaboratory 

studies, Standard Reference Materials (SRMs) and control materials, and methods development and 

validation. Serum-based samples with assigned values for the target analytes (retinol, alphatocopherol, gamma/beta-tocopherol, trans- and total beta-carotene, and ascorbic acid) and 

performance-evaluation standards are distributed by NIST to laboratories for analysis. 

Participants use the methodology of their choice to determine analyte content in the control and 

study materials. Participants provide their data to NIST, where it is compiled and evaluated for 

trueness relative to the NIST value, within-laboratory precision, and concordance within the 

participant community. NIST provides the participants with a technical summary report concerning 

their performance for each exercise and suggestions for methods development and refinement. 

Participants who have concerns regarding their laboratory’s performance are encouraged to consult 

with the MMQAP coordinators. 

All MMQAP interlaboratory studies consist of individual units of batch-prepared samples that are 

distributed to each participant. For historical reasons these studies are referred to as “Round 

Robins”. The MMQAP program and the nature of its studies are described elsewhere. [1,2] 

Round Robin XLV: Fat-Soluble Vitamins and Carotenoids in Human Serum 

Participants in the MMQAP Fat-Soluble Vitamins and Carotenoids in Human Serum Round Robin 

XLV comparability study (hereafter referred to as RR45) received four lyophilized human serum test 

samples for analysis. Unless multiple vials were previously requested, participants received one vial 

of each serum. These sera were shipped on dry ice to participants in January 1999. The 

communication materials included in the sample shipment are provided in Appendix A. 

Participants are requested to report values for all fat-soluble vitamin-related analytes that are of 

interest to their organizations. Not all participants report values for the target analytes, and many 

participants report values for non-target analytes. 

The final report delivered to every participant in RR45 consists of three documents: 

•	 A cover letter for the current study, a brief description of the other two documents, and a 

discussion of our analysis of the overall results that may be of broad interest. This cover 

letter is reproduced as Appendix B. 

•	 The “All-Lab Report” that lists all of the reported measurement results, a number of 

consensus statistics for analytes reported by more than one participant, and the mean median 

and pooled SD from any prior distributions of the serum. This report also provides a 

numerical “score card” for each participant’s measurement comparability for the more 

commonly reported analytes. This report is reproduced as Appendix C. 

1
 
 

 

 

 

 

 

 

 

•	 An “Individualized Report” that graphically analyzes each participant’s results for selected 

analytes. This report also provides a graphical summary of their measurement comparability. 

The graphical tools used in this report are described in detail elsewhere [3]. An example 

“Individualized Report” is reproduced as Appendix D. 

Round Robin XLVI: Fat-Soluble Vitamins and Carotenoids in Human Serum 

Participants in the MMQAP Fat-Soluble Vitamins and Carotenoids in Human Serum Round Robin 

XLVI comparability study (hereafter referred to as RR46) received four lyophilized human serum 

test samples for analysis. Unless multiple vials were previously requested, participants received one 

vial of each material. These sample materials were shipped on dry ice to participants in June 1999. 

The communication materials included in the sample shipment are provided in Appendix E. 

Participants are requested to report values for all fat-soluble vitamin-related analytes that are of 

interest to their organizations. Not all participants report values for the target analytes, and many 

participants report values for non-target analytes. 

The final report delivered to every participant in RR46 consists of three documents: 

•	 A cover letter for the current study, a brief description of the other two documents, and a 

discussion of our analysis of overall results that may be of broad interest. This cover letter is 

reproduced as Appendix F. 

•	 The “All-Lab Report” that lists all of the reported measurement results, a number of 

consensus statistics for analytes reported by more than one participant, and the mean median 

and pooled SD from any prior distributions of the serum. This report also provides a 

numerical “score card” for each participant’s measurement comparability for the more 

commonly reported analytes. This report is reproduced as Appendix G. 

•	 An “Individualized Report” that graphically analyzes each participant’s results for selected 

analytes. This report also provides a graphical summary of their measurement comparability. 

The graphical tools used in this report are described in detail elsewhere [3]. An example 

“Individualized Report” is reproduced as Appendix H. 

Round Robin 12: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 12 comparability study 

(hereafter referred to as RR12) received four frozen serum test samples and a solid ascorbic acid 

control material for analysis. Two of the test samples were identified as levels 1 and 2 of SRM 970. 

The other two samples were also levels 1 and 2 of SRM 970, but were identified only as 

“Unknowns”. These sample materials were shipped on dry ice to participants in February 1999. 

The communication materials included in the sample shipment are provided in Appendix I. 

Participants were asked to provide two results for each vial and were asked to prepare and evaluate a 

standard solution of 50 μmol ascorbic acid (AA) per L solution of 5 % by mass metaphosphoric 

acid. 

2
 
 

 

No report on participant results was prepared for just RR12. Rather, a “Final Report” for the 

combination of RR11 and RR12 was distributed to all participants in RR11 and/or RR12 in August 

1999. This report consisted of: 

•	 A cover letter and summary analysis of the results from RR11 and/or RR12. This report is 

reproduced as Appendix J. It contains the following tables and figure: 

a.	 Table 1: Round Robin 11 and 12 for the Measurement of AA in Human Serum. 

b.	 Table 2: Vitamin C Round Robin 11. 

Note: Table 2 is equivalent to the usual “All Lab Report” for RR11. 

c.	 Table 3: Vitamin C Round Robin 12. 

Note: Table 3 is equivalent to the usual “All Lab Report” for RR12. 

d.	 Figure 1: Distribution of Participant Results in Round Robins 11 and 12. 

•	 An “Individualized Report” that graphically analyzes each participant’s results including a 

graphical summary of their measurement comparability. The graphical tools used in this 

report are described in detail elsewhere [3]. An example “Individualized Report” is 

reproduced as Appendix K. 

With certified values based partially on the results from RR11 and RR12, SRM 970 was released for 

sale on May 18, 2000. 

References 

1 Duewer DL, Brown Thomas J, Kline MC, MacCrehan WA, Schaffer R, Sharpless KE, May WE, 

Crowell JA. NIST/NCI Micronutrients Measurement Quality Assurance Program: Measurement 

Repeatabilities and Reproducibilities for Fat-Soluble Vitamin-Related Compounds in Human 

Sera. Anal Chem 1997;69(7):1406-1413. 

2 Margolis SA, Duewer DL. Measurement Of Ascorbic Acid in Human Plasma and Serum: 

Stability, Intralaboratory Repeatability, and Interlaboratory Reproducibility. Clin Chem 

1996;42(8):1257-1262. 

3 Duewer DL, Kline MC, Sharpless KE, Brown Thomas J, Gary KT, Sowell AL. Micronutrients 

Measurement Quality Assurance Program: Helping Participants Use Interlaboratory Comparison 

Exercise Results to Improve Their Long-Term Measurement Performance. Anal Chem 

1999;71(9):1870-1878. 

3
 
 

Appendix A. Shipping Package Inserts for RR45 

The following two items were included in each package shipped to an RR45 participant: 

• Cover letter 

• Datasheet 

The cover letter and datasheet were enclosed in a sealed waterproof bag along with the 

samples themselves. 

A1
 
UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

January 25, 1999 

Dear Colleague: 

Enclosed is the set of samples for the first quality assurance round robin exercise (Round Robin XL V) for 

FY99. You will find one vial of each of four lyophilized serum samples for analysis along with a form 

for reporting your results. When reporting your results, please submit one value for each analyte for a 

given serum sample. If an obtained value is below your limit of quantitation, please indicate this result on 

the form by using NQ (Not Quantitated). For analytes not measured, please leave a blank. Results are 

due to NIST by April 2, 1999. Results received two weeks after the due date will not be included in the 

summary report for this round robin study. The feedback report concerning the study will be provided 

around the end of April. 

Samples should be reconstituted with 1.0 mL ofHPLC-grade water or equivalent. We recommend that 

dissolution be facilitated with 3 to 5 min agitation in an ultrasonic bath or at least 30 min at room 

temperature with intermittent swirling. (CAUTION: Vigorous shaking will cause foaming and possibly 

interfere with accurate measurement. The rubber stopper contains phthalate esters that will leach into the 

sample upon intermittent contact of the liquid sample with the stopper. These esters absorb strongly in the 

UV region and elute very near retinal in most LC systems creating analytical problems.) Pipette a known 

volume of serum from the vial for analysis. (The final volume of the reconstituted sample is greater than 

1.0 mL.). For consistency, we request that laboratories use the following absorptivities (E 1 % cm) in 

ethanol: retinal, 1843 at 325 nm; retinyl palmitate, 975 at 325 nm; a-tocopherol, 75.8 at 292 nm; 

y-tocopherol, 91.4 at 298 nm; a-carotene, 2800 at 444 nm (in hexane); ~-carotene, 2560 at 450 nm (in 

ethanol), 2592 at 452 nm (in hexane); lycopene, 3450 at 472 nm (in hexane). 

Please mail or fax your results for Round Robin XL V to: 

Micronutrients Measurement Quality Assurance Program 

NIST 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 

Fax: (301) 977-0685 

If you have questions regarding this round robin exercise, please call me at (301) 975-3120; 

e-mail me atjeanice.brownthomas@nist.gov; or mail/fax queries to the above address. 

in~rely: ~ fh lntkf 

'j"nice Brown Tbo1~ esearch Chemist 

alytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

cc: S. Wise 

L. Sander 

------

N•Si 

A2
 
 

 

NIST 

Micronutrients Measurement Quality Assurance Program 

Round Robin XLV Results from Laboratory #_____ 

Serum 

Analyte 251 252 253 254 Units* 

retinol 

retinyl palmitate 

α-tocopherol 

γ-tocopherol 

δ-tocopherol 

total β-carotene 

trans-β-carotene 

total cis-β-carotene 

total α-carotene 

trans-α-carotene 

total lycopene 

trans-lycopene 

β-cryptoxanthin 

α-cryptoxanthin 

“lutein” 

“zeaxanthin” 

“lutein&zeaxanthin” 

Other Analytes?
 

* We prefer mg/mL 

Today's Date: 

Comments? 

Mail: MMQAP, 222/B208 

NIST Please return results on-or-before Fax: 301-977-0685 

Gaithersburg, MD 20899 2-Apr-99 Email: David.Duewer@NIST.gov 

A3
 
 

 

Appendix B. Final Report for RR45 

The following ten pages are the final report as provided to all participants: 

•	 Cover letter 

•	 An information sheet that: 

o	 describes the contents of the “All-Lab” report 

o	 describes the content of the “Individualized” report 

o	 describes the nature of the test samples and details any previous distributions 

o	 summarizes aspects of the study that we believe may be of interest to the 

participants 

B1
 
May 19, 1999 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20888-

Enclosed is the summary report of the results for Round Robin XL V (RR 45). Included in this 

report are: a summary of data for all laboratories; the measurement comparability summary for 

evaluating laboratory performance; a summary of individual laboratory performance and 

interlaboratory accuracy and precision; and a summary of the NIST assigned value (NAV) vs. 

your laboratory value for the analytes measured. As in previous reports, the NIST assigned 

values are derived from the equally weighted results from the analyses performed by NIST and 

the laboratories that participated in this interlaboratory comparison exercise. 

Serum samples (Sera 251-254) distributed in RR 45 were also analyzed in previous round robin 

exercises. Serum 25 was distributed as Serum 242 in RR 42. Serum 252 was originally prepared 

in 1987 as Control D and was distributed as Serum 78inRR12 and as Serum 163 in RR 24. 

Serum 25 3 was previously distributed as Sera 182 and 185 (blind replicates) in RR 28 and as 

Serum 216 in RR 36. Serum 254 was previously distributed as Serum 192 in RR 30. 

Data for evaluating laboratory performance in RR 45 are provided in the comparability summary 

(Score Card) on page 6 of the "All Lab Report." Laboratory comparability is summarized as 

follows: results rated 1-3 are within 1-3 standard deviation(s) of the assigned value; those rated 4 

are >3 standard deviations from the assigned value. 

If you have concerns regarding your laboratory performance, we suggest that you obtain a unit of 

SRM 968b, Fat-Soluble Vitamins and Cholesterol in Human Serum, and analyze all three levels. 

If your measured values do not agree with the certified values, we suggest that you contact us for 

consultation. 

The QA workshop was held on April 16 prior to Experimental Biology '99 in Washington, DC. 

There were more than 50 people in attendance; the exchange of information and ideas was 

invaluable. QA participants suggested that we continue to hold future workshops in conjunction 

with Experimental Biology. We tentatively plan to hold the next workshop in 2001 in Orlando, 

FL. 

In the last correspondence, I mentioned that we plan to make available, at a nominal cost, a 

limited supply of well-characterized serum pools that were used in previous intercomparison 

exercises for the QA program. These samples are currently being evaluated for value assignment. 

Once the evaluation is complete, we will notify you when the samples are available. 

We plan to hold the tutorial for Fat-Soluble Vitamin and Carotenoid Analysis on October 18, 

1999 at NIST. This tutorial will be primarily for new laboratories and/ or lab personnel, or for 

those currently experiencing difficulties with analysis. As in the past, this session will include a 

discussion of calibration, sample preparation, and chromatographic techniques for measuring fatB2
 NISI 
soluble vitamins and carotenoids in serum. In addition, we will also hold a session for ascorbic 

acid analysis if there is sufficient interest. There will be no fee for these sessions. We will 

provide you with more details as we finalize the plans. 

Enclosed you will also find reprints on the preparation and value assignment of Standard 

Reference Material 2383 (Baby Food Composite) and on the use ofinterlaboratory comparison 

exercise results. 

2 

The next set of samples for the fat-soluble vitamins in serum analysis will be distributed during 

the week of June 21, 1999. Results will be due September 1 O; written feedback ~ll be provided 

during the first week in October. 

If you have any questions regarding this report, please contact me at 301/975-3120; FAX: 

301/977-0685; e-mail: jeanice.brownthomas@nist.gov. 

~cerely, . 

~1\ttCJL 

Jeanice Brown Thomas 

Research Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

cc: S. A. Wise 

L. C. Sander 

Enclosures 

B3
 
The NIST M2

QAP Round Robin XLV (RR45) report includes the usual 

Page “All Lab” Report 

1-4 A listing of all results and statistics for analytes reported by at least two laboratories 

5 A list of results for the analytes reported by only one laboratory and a legend for the above 

two lists 

6 The “Measurement Comparability Summary” (or “Score Card”) 

and a completely redesigned 

Page “Individualized” Report 

1 Your values, the number of labs reporting values, and our assigned values. 

2+ “Four Plot” summaries of your current and past measurement performance, one page for 

each analyte you report that is also reported by at least 10 other participants. 

The design and interpretation of the “Four Plot” graphical tools is discussed in detail in: Duewer DL, 

Kline MC, Sharpless KE, Brown Thomas J, Gary KT. Micronutrients Measurement Quality Assurance 

Program: Helping Participants Use Interlaboratory Comparison Exercise Results to Improve Their Longterm Measurement Performance. Anal Chem 1999; 71:1074-9. 

Samples. Four “old” sera were distributed in RR45. The sera were selected from our -80 oC archives to:
 

1) monitor interference-artifacts from low-level plasticizer components, 2) evaluate analyte stability in
 

our lyophilized sera, and 3) evaluate interlaboratory performance at low and high analyte levels.
 

Serum #251 is a manipulated serum, augmented with many analytes. We now know it has low levels of
 

plasticizer components from the blood bank’s original storage bag. This serum was originally distributed
 

as #242 (RR42,4/98). 

Serum #252 is a native serum, originally prepared as the low-analyte level “Control D” back in 1987. In 

addition to its use as a control material, this serum was distributed as #78 (RR12,4/88) and #163 

(RR24,4/92). 

Serum #253 is a low-to-medium-analyte level native serum, previously distributed as the blind replicates 

#182 and #185 (RR28,6/93) and as #216 (RR36,3/96). 

Serum #254 is a medium-to-high-analyte level augmented serum, previously distributed as #192 

(RR30,3/94). Approximately 30% of the “retinol” in this serum is a mixture of cis-retinol isomers.
 

Qualitative Results. 

1) Three participants noted the presence of one or more unusual peaks in serum #251 eluting between 

retinol and their retinyl acetate internal standard (IS). Many more participants reported these peaks 

when this serum was distributed in RR42. Rather than reflecting chromatographic changes, this lower 

observation rate is most likely related to #251 being the only contaminated sample in RR45 rather 

than the all four of RR42. 

You may be able to identify whether or not your system is subject to plasticizer interference by 

examining your relative concordances of serum #251 relative to those of #252-254. If all analytes 

normalized to (one of) your IS(s) are unusually low, it’s likely that there is an interferent coeluting 

B4
 
 

with the IS peak. If just one analyte is unusually high in #251, the interferent coelutes with that 

analyte. If you suspect that you do have an unrecognized problem, double-check your chromatograms 

for odd asymmetries. Although these specific interferences may not be important to you, your 

measurement system should routinely recognize and report unusual performance. 

2) On detailed examination of the RR42 and RR45 retinol data for serum #254, a number of participants 

(including NISTb) have twice reported the same quite low [retinol]. This suggests a systematic 

sample-specific discordance. NISTb and one other participant noted small peaks before/in the leading 

edge of the retinol peak in all four sera, with an exceptionally large shoulder on the retinol in #254. 

On reanalysis of the retinol peak in serum #254, we believe more than one-third of the total area is 

attributable to a mixture of cis-retinol isomers. It is probable that the retinol used to spike serum #254 

contained little or no trans-retinol: that was in late 1993 and the actual spiking material used is 

depleted. The “true” level of retinol in serum #254 ranges from about 0.65 μg/mL (trans-retinol) to 

1.1 μg/mL (total retinol). We expect the reported values for non-specific retinol in serum #254 to 

depend upon separation conditions and/or integration parameters: the “Score Card” evaluation for 

retinol thus does not include serum #254. 

While there are numerous literature methods for separating the retinol isomers (see, just for instance: 

MacCrehan WA, Schonberger E. Reversed-phase high-performance liquid chromatographic 

separation and electrochemical detection of retinol and its isomers. J Chromatogr 1987;417(1):65-78), 

there is little on their clinical/nutritive activities other than the rat bioassay potencies reported in: 

Weiser H, Somorjai G. Bioactivity of cis and di-cis isomers of vitamin A esters. Int J Vit Nutr Res 

1992;62(3):201-8. There are two AOAC methods for retinol, one explicitly weighting the retinol 

isomers by the biological activities reported by Weiser and the other adding all isomers with equal 

weight. We have limited information on the prevalence of cis-retinol in “real” samples, but two 

participants have confirmed that they occasionally do see small peaks or shoulders on the retinol 

leading edge. The literature suggests cis-retinols can be at least 40% of the “total retinol” in hightemperature-processed and/or bio-converted milk products. 

The majority of M2

QAP participants appear to be observing and reporting “total retinol”; however, it 

is clear that we need explicitly to make clear what analyte(s) are actually being reported. Starting 

with RR46, we will provide space for both “total retinol” and “trans-retinol” in the reports. We ask 

that you examine your chromatograms and integration protocol and determine which form you 

actually measure. 

Note: In an attempt to avoid further confusion, we now explicitly state what we believe is “the form” 

of all analytes having geometric isomers. If you disagree with our assignments for your 

measurements (i.e., you have been measuring “trans-β-cryptoxanthin” but we have assigned it as 

“Total β-cryptoxanthin”), please let us know and we will correct the historical data. 

Quantitative Results 

1)	 The only noted interference artifacts are discussed above. 

2)	 There is no evidence for any analyte that any of the four sera have significantly degraded in storage, 

either in change of medians or in increased interlaboratory variability. Note that serum #252 has 

been in storage at -80 oC for more than a decade. 

3)	 Due to shipping errors on our part, both Prof. Olmedilla (Clìnica Puerta de Hierro, Madrid) and Neal 

Matthews (Medical Research Council - Resource Centre for Human Nutrition Research, Cambridge) 

received sets of RR45 sera that had been at or above room temperature for several days. They 

B5
 

 

graciously agreed to analyze these “aged” sera in tandem with sets shipped and received on dry ice. 

They observed no significant differences in [retinol], [α-tocopherol], or [γ-tocopherol] in any sera. 

They did observe significant decreases in [β-carotene] and [retinyl palmitate] in the “aged” sera, 

particularly in serum #251. Thus there may be a serum-matrix specific “aging” problem with the 

most hydrophobic analytes. If someone is interested in doing a designed accelerated aging study, we 

will enthusiastically collaborate! 

4)	 Figures 1a and 1b present our newly-revised expected relationships between interlaboratory 

measurement standard deviation (SD) and the interlaboratory median levels. These plots use only 

data from the 12 most recent M2

QAP exercises: RR33 through RR45. For details of the 

interpretation of these plots, please see: Duewer DL, Brown Thomas J, Kline MC, MacCrehan WA, 

Schaffer R, Sharpless KE, May WE, Crowell JA. NIST/NCI Micronutrients Measurement Quality 

Assurance Program: Measurement Repeatabilities And Reproducibilities For Fat-Soluble 

Vitamin-Related Compounds In Human Sera. Anal Chem 1997:69;1406-13. 

5)	 Figures 2a through 2c introduce our current investigations into diagnostic tools for improving 

measurement performance, displaying the median comparability, (absolute value of) concordance 

(|Con|), and apparent precision (AP) for three analytes in past M2

QAP interlaboratory exercises. The 

x-axis is the approximate exercise completion date; the y-axis is in “expected interlaboratory SD” 

units as defined in Figures 1a and 1b. (For definitions of these terms, see Anal Chem 1999; 71:1074­

9.) 

Figure 2a displays the performance metrics for total β-carotene for all fat-soluble RRs. (Retinol and 

α-tocopherol look very similar.) Comparability improved continuously during the first few years of 

the program, was “best” during the period in which control materials were distributed along with the 

unknowns, rose slowly after the (free) control materials were discontinued after the (not free) SRM 

968 materials became available, and has settled to a nearly constant level since 1993. Note that AP is 

the limiting component of comparability for this analyte. There is general agreement among 

laboratories; comparability is limited by among-sample differences: heterogeneity, matrix effects, 

and/or within-laboratory measurement variability. 

Figure 2b displays the same metrics for total lycopene. Note that comparability appears to be slowly 

improving but is limited by discordance among laboratories. Different laboratories are using 

disparate calibration materials and/or including different mixes of lycopene isomers (and/or other 

carotenoids) in their reported values. Individual laboratories may be more consistently reporting the 

same mix of “lycopene” components in different samples but more uniform analytical techniques and 

materials must be adopted to improve interlaboratory comparability for this analyte. 

Figure 2c displays the metrics for total α-carotene. In contrast to lycopene, comparability does not 

appear to have much improved over time and appears to be limited by among-sample rather than 

among-laboratory measurement differences. 

B6
 
 

 

Standard Deviation, 

μg/mL 

Retinol 

SD = (0.0152 + (0.084*X1.12)2)0.5 

Retinyl palmitate 

SD = (0.0162 + (0.18*X0.80)2)0.5 

α-Tocopherol 

SD = (0.452 + (0.036*X1.26)2)0.5 

Total and trans-β-Carotene 

SDTotal = (0.0082 + (0.13*X0.88)2)0.5 

SDtrans = (0.0062 + (0.10*X0.93)2)0.5 

γ-Tocopherol 

SD = (0.0512 + (0.12*X0.80)2)0.5 

Total α-Carotene 

SD = (0.0032 + (0.25*X0.96)2)0.5 

Median [Analyte], μg/mL
 

Figure 1a
 

B7
Total Lycopene trans-Lycopene 

SD = (0.0012 + (0.20*X0.83)2)0.5 SD = (0.0052 + (0.21*X1.02)2)0.5 

Standard Deviation, 

μg/mL 

Median [Analyte], μg/mL 

β-Cryptoxanthin 

SD = (0.0022 + (0.19*X0.89)2)0.5 

Lutein 

SD = (0.0012 + (0.23*X1.02)2)0.5 

Zeaxanthin 

SD = (0.0032 + (0.34*X1.06)2)0.5 

Lutein&Zeaxanthin 

SD = (0.0042 + (0.23*X1.03)2)0.5 

Figure 1b 

B8
 
B9

96: 99 Median Perf ormance, SD

Total β-Carotene

1986 1989 1992 1995 1998 

Number of Participants

Expected Deviation

|Concordance|

Apparent Precision 

Ctrl A-D 

21

0 

Date Study Completed 

Figure 2a 
B10

96: 99 Median Perf ormance, SD

Total Lycopene

1986 1989 1992 1995 1998 

Number of Participants

Expected Deviation

|Concordance|

Apparent Precision 

Ctrl A-D 

21

0 

Date Study Completed 

Figure 2b 
B11

96: 99 Median Perf ormance, SD

Total α-Carotene

1986 1989 1992 1995 1998 

Number of Participants

Expected Deviation

|Concordance|

Apparent Precision 

Ctrl A-D 

21

0 

Date Study Completed 

Figure 2c 
 

 

Appendix C. “All-Lab Report” for RR45 

The following six pages are the “All-Lab Report” as provided to all participants, with two 

exceptions: 

• the participant identifiers (Lab) have been altered. 

• the order in which the participant results are listed has been altered. 

The data summary in the “All-Lab Report” has been altered to ensure confidentiality of 

identification codes assigned to laboratories. The only attributed results are those 

reported by NIST. The NIST results are not used in the assessment of the consensus 

summary results of the study. 

C1
 
Round Robin XLV Laboratory Results 

All Values in μg/mL 

Retinol Retinyl Palmitate α-Tocopherol γ-Tocopherol δ-Tocopherol 

Lab 251 252 253 254 

FSV-BA 0.952 0.394 0.571 1.210 

FSV-BB 0.975 0.402 0.619 1.171 

FSV-BBa 

FSV-BD 0.856 0.360 0.514 1.015 

FSV-BE 0.909 0.380 0.511 1.028 

FSV-BF 0.943 0.394 0.445 1.024 

FSV-BG 0.939 0.390 0.543 1.105 

FSV-BGa 1.027 0.388 0.555 1.150 

FSV-BH 0.872 0.342 0.492 0.870 

FSV-BI 0.929 0.405 0.581 1.118 

FSV-BJ 0.901 0.378 0.532 1.091 

FSV-BK 0.930 0.385 0.547 1.075 

FSV-BL 0.920 0.320 0.490 0.630 

FSV-BM 0.904 0.386 0.549 1.109 

FSV-BN 0.954 0.389 0.547 1.116 

FSV-BO 0.832 0.335 0.458 0.716 

FSV-BP 0.957 0.411 0.590 1.113 

FSV-BQ 0.990 0.386 0.558 1.156 

FSV-BR 1.030 0.430 0.630 1.200 

FSV-BS 1.198 0.452 0.617 0.831 

FSV-BT 0.723 0.364 0.497 0.975 

FSV-BU 0.960 0.405 0.574 1.164 

FSV-BV 1.020 0.440 0.620 1.160 

FSV-BW 0.958 0.384 0.533 1.042 

FSV-BX 0.924 0.402 0.579 1.017 

FSV-BZ 

FSV-CB 1.028 0.409 0.590 1.101 

FSV-CC 0.913 0.373 0.566 0.857 

FSV-CD 0.833 0.312 0.437 0.906 

FSV-CE 0.864 0.346 0.496 0.977 

FSV-CF 0.984 0.403 0.582 1.130 

FSV-CG 1.175 0.445 0.631 1.152 

FSV-CH 0.724 0.315 0.501 0.875 

FSV-CI 1.030 0.380 0.560 0.770 

FSV-CL 0.611 0.289 0.424 0.951 

FSV-CP 

FSV-CR 1.020 0.410 0.570 1.080 

FSV-CS 0.922 0.385 0.550 1.125 

FSV-CU 0.868 0.369 0.523 1.087 

FSV-CV 0.951 0.399 0.573 1.104 

FSV-CX 0.870 0.300 0.390 0.440 

FSV-DB 0.899 0.371 0.526 1.050 

FSV-DF 0.806 0.294 0.519 1.029 

FSV-DH 0.930 0.400 0.570 1.110 

FSV-DK 0.970 0.400 0.550 1.100 

FSV-DP 0.834 0.356 0.505 0.974 

FSV-DR 1.020 0.415 0.630 1.140 

FSV-DU 1.150 0.380 0.490 0.990 

FSV-EH 0.918 0.399 0.542 1.019 

FSV-EM 0.950 0.430 0.610 1.060 

FSV-EQ 0.899 0.414 0.571 0.991 

FSV-ES 0.994 0.424 0.596 1.210 

251 252 253 254 

0.068 0.022 0.065 0.071 

0.040 0.016 0.048 0.037 

0.06 0.02 0.03 0.04 

0.08 0.04 0.07 0.08 

0.07 0.03 0.06 0.05 

nq nq nq nq 

nd nd 0.05 nd 

nq nq nq nq 

0.03 0.02 0.07 0.02 

0.03 0.01 0.04 0.02 

0.03 nd 0.06 0.03 

0.10 0.01 0.06 0.10 

0.05 0.03 0.04 0.06 

0.05 0.05 0.07 0.08 

0.03 0.01 0.04 0.01 

0.12 0.42 0.37 0.16 

0.04 0.03 0.07 0.03 

251 252 253 254 

19.42 5.48 5.56 25.56 

20.28 5.22 5.27 25.13 

21.48 5.35 5.46 26.00 

20.30 5.60 5.50 26.10 

20.89 5.75 5.43 26.99 

23.36 5.72 4.85 29.42 

21.74 5.58 5.64 27.52 

21.97 5.72 5.65 28.06 

20.35 5.39 5.32 25.63 

21.94 6.43 6.04 27.28 

22.98 6.08 5.68 29.06 

20.30 5.60 5.50 25.70 

19.38 4.31 3.88 11.20 

21.70 5.40 5.60 27.20 

20.71 5.18 5.33 26.09 

21.10 5.60 5.73 26.75 

19.52 5.21 5.18 25.12 

18.80 5.00 5.00 24.20 

17.58 4.69 4.56 23.13 

22.04 6.26 5.94 29.19 

20.45 5.94 5.41 25.15 

19.76 5.17 5.21 26.45 

21.47 6.05 6.06 28.27 

19.50 5.00 6.10 26.50 

21.01 5.58 5.55 26.81 

21.83 5.62 5.57 26.30 

20.10 5.29 5.21 26.13 

19.99 5.29 5.36 26.04 

22.40 6.00 6.00 28.40 

20.76 5.51 5.75 26.10 

19.86 5.60 6.31 24.91 

18.90 4.90 4.60 26.80 

22.71 5.82 6.38 32.58 

18.95 5.14 4.71 23.72 

19.80 5.90 5.40 26.00 

21.60 5.21 5.02 27.52 

16.91 5.12 5.71 25.19 

17.21 6.12 5.99 20.70 

20.42 5.56 5.51 26.33 

18.27 4.79 4.73 24.32 

21.55 5.95 5.92 29.27 

18.90 5.34 5.12 25.13 

24.17 5.99 6.28 29.81 

25.05 5.40 5.10 28.31 

22.87 4.98 4.82 30.46 

16.40 5.33 4.44 21.76 

22.70 6.46 6.35 27.34 

21.00 6.16 6.01 29.00 

251 252 253 254 

1.78 3.32 2.51 5.86 

1.63 3.16 2.37 5.69 

1.56 3.09 2.32 5.51 

1.56 3.63 2.50 6.36 

1.73 3.26 2.19 6.06 

1.69 3.50 2.61 6.41 

1.55 3.11 2.37 5.30 

1.45 2.82 2.11 5.08 

1.80 3.41 2.58 6.13 

1.99 3.77 2.69 6.76 

1.65 3.08 2.29 5.38 

1.54 2.93 2.15 5.73 

2.65 4.34 3.59 7.06 

1.59 3.29 2.46 5.63 

1.54 3.15 2.34 5.80 

1.70 3.55 2.69 6.23 

2.60 2.80 3.20 5.00 

1.43 3.08 2.23 5.70 

2.01 3.51 2.80 6.23 

1.40 2.78 2.33 4.87 

1.40 3.00 2.20 5.80 

0.94 2.83 2.29 6.19 

1.82 2.92 2.07 5.40 

1.60 3.20 2.29 6.18 

1.71 3.54 2.59 12.36 

1.76 3.50 2.50 6.31 

2.62 4.14 3.38 6.61 

1.57 3.27 2.29 6.49 

251 252 253 254 

0.699 0.215 0.205 0.638 

1.297 0.492 0.465 0.818 

1.576 0.530 0.448 0.870 

0.700 <0.3 <0.3 <0.3 

0.641 0.213 0.165 0.424 

N 49 49 49 49 14 13 15 14 48 48 48 48 28 28 28 28 5 4 4 4 

Min 0.611 0.289 0.390 0.440 0.027 0.008 0.033 0.010 16.40 4.31 3.88 11.20 0.94 2.78 2.07 4.87 0.641 0.213 0.165 0.424 

Median 0.930 0.388 0.550 1.075 0.052 0.022 0.059 0.043 20.58 5.54 5.50 26.31 1.64 3.23 2.37 5.96 0.700 0.353 0.326 0.728 

Max 1.198 0.452 0.631 1.210 0.122 0.418 0.374 0.161 25.05 6.46 6.38 32.58 2.65 4.34 3.59 12.36 1.576 0.530 0.465 0.870 

eSD 0.063 0.027 0.050 0.105 0.028 0.010 0.015 0.037 1.67 0.46 0.47 1.84 0.17 0.33 0.23 0.54 0.444 

eCV 7 7 9 10 54 47 25 86 8 8 8 7 11 10 10 9 63 

Npast 47 38 46 44 9 0 10 6 46 35 45 44 21 16 18 20 0 0 5 0 

Medianpast 0.914 0.394 0.544 1.027 0.067 0.069 0.048 20.78 5.55 5.47 27.13 1.67 3.26 2.49 6.38 0.183 

SDpast 0.081 0.040 0.050 0.107 0.019 0.016 0.055 1.62 0.69 0.40 2.55 0.25 0.29 0.24 0.64 0.076 

NISTa 0.935 0.377 0.585 0.977 20.24 5.07 5.15 26.44 1.53 3.25 2.34 5.42 0.438 nq nq 0.249 

NISTb 0.845 0.353 0.501 0.879 21.43 5.50 5.24 27.18 1.70 3.40 2.46 6.25 0.685 0.192 0.121 0.406 

NNIST 4 4 4 4 4 4 4 4 4 4 4 4 4 2 2 4 

Mean 0.890 0.365 0.543 0.928 20.84 5.28 5.20 26.81 1.61 3.32 2.40 5.84 0.562 0.192 0.121 0.328 

Srep 0.010 0.029 0.014 0.060 0.79 0.22 0.06 0.73 0.02 0.07 0.04 0.12 0.020 0.001 0.008 0.031 

Shet 0.015 0.009 0.006 0.011 0.05 0.04 0.05 0.51 0.03 0.04 0.02 0.06 0.023 0.004 0.007 0.022 

Sanl 0.064 0.017 0.060 0.069 0.84 0.31 0.06 0.52 0.12 0.10 0.08 0.59 0.175 0.111 

SNIST 0.066 0.035 0.062 0.093 1.16 0.38 0.10 1.03 0.13 0.13 0.09 0.60 0.177 0.004 0.011 0.117 

NAV 0.910 0.377 0.546 1.004 0.052 0.022 0.059 0.043 20.71 5.43 5.35 26.56 1.63 3.28 2.38 5.90 0.631
 

NAU
 0.084 0.039 0.062 0.150 0.028 0.010 0.015 0.037 1.68 0.58 0.59 2.27 0.19 0.36 0.25 0.61 0.455 

All Lab Report Page 1 / 6 

C2
 
Round Robin XLV Laboratory Results 

All Values in μg/mL 

Total β-Carotene trans-β-Carotene Total cis-β-Carotene Total α-Carotene 

Lab 251 252 253 254 

FSV-BA 0.628 0.193 0.411 0.396 

FSV-BB 0.681 0.188 0.415 0.391 

FSV-BBa 0.595 0.167 0.366 0.316 

FSV-BD 0.73 0.19 0.37 

FSV-BE 0.696 0.195 0.419 0.439 

FSV-BF 

FSV-BG 0.720 0.201 0.417 0.359 

FSV-BGa 0.726 0.219 0.457 0.426 

FSV-BH 0.425 0.181 0.397 0.377 

FSV-BI 0.698 0.184 0.396 0.356 

FSV-BJ 0.540 0.184 0.407 0.370 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.752 0.187 0.360 0.358 

FSV-BO 0.523 0.158 0.349 0.344 

FSV-BP 0.563 0.197 0.419 0.440 

FSV-BQ 

FSV-BR 

FSV-BS 0.643 0.146 0.370 0.327 

FSV-BT 0.604 0.151 0.312 0.297 

FSV-BU 0.711 0.200 0.430 0.389 

FSV-BV 0.790 0.190 0.420 0.380 

FSV-BW 0.559 0.160 0.352 0.357 

FSV-BX 0.726 0.209 0.405 0.382 

FSV-BZ 0.590 0.387 0.533 0.543 

FSV-CB 0.661 0.182 0.388 0.376 

FSV-CC 

FSV-CD 0.506 0.119 0.264 0.241 

FSV-CE 0.658 0.177 0.379 0.335 

FSV-CF 

FSV-CG 0.701 0.194 0.432 0.408 

FSV-CH 0.460 0.119 0.249 0.246 

FSV-CI 

FSV-CL 0.561 0.150 0.326 0.346 

FSV-CP 0.549 0.173 0.377 0.341 

FSV-CR 

FSV-CS 0.561 0.171 0.429 0.371 

FSV-CU 

FSV-CV 0.588 0.169 0.464 0.366 

FSV-CX 

FSV-DB 0.588 0.159 0.397 0.346 

FSV-DF 

FSV-DH 0.702 0.231 0.565 0.435 

FSV-DK 0.310 0.149 0.332 0.287 

FSV-DP 

FSV-DR 1.060 0.270 0.470 0.370 

FSV-DU 

FSV-EH 0.698 0.213 0.405 0.376 

FSV-EM 0.410 0.144 0.343 0.286 

FSV-EQ 0.775 0.189 0.411 0.365 

FSV-ES 

0.30 

251 252 253 254 

0.602 0.181 0.393 0.374 

0.655 0.179 0.403 0.348 

0.572 0.159 0.355 0.297 

0.405 0.171 0.382 0.344 

0.696 0.163 0.351 0.312 

0.581 0.143 0.299 0.269 

0.671 0.181 0.380 0.315 

0.560 0.370 0.520 0.510 

0.669 0.180 0.413 0.374 

0.520 0.159 0.397 0.332 

0.300 0.130 0.360 0.290 

0.663 0.213 0.533 0.374 

0.380 0.090 0.260 0.200 

0.668 0.201 0.387 0.350 

0.471 0.138 0.317 0.261 

251 252 253 254 

0.026 0.012 0.018 0.022 

0.026 0.009 0.012 0.058 

0.023 0.008 0.011 0.025 

0.020 0.010 0.015 0.033 

0.057 0.032 0.042 0.052 

0.022 0.008 0.013 0.027 

0.055 0.027 0.025 0.067 

0.030 0.017 0.013 0.033 

0.032 0.014 0.019 0.034 

0.041 0.012 0.032 0.039 

0.039 0.018 0.032 0.061 

0.030 0.012 0.018 0.026 

251 252 253 254 

0.076 0.007 0.014 0.012 

0.076 0.008 0.012 0.010 

0.096 0.016 0.016 0.026 

0.080 0.019 0.015 0.050 

0.120 0.009 0.014 0.014 

0.094 0.008 0.012 0.010 

0.091 nq nq nq 

0.109 0.012 0.016 0.014 

0.131 0.009 0.015 0.013 

0.025 0.024 0.020 0.104 

0.111 0.014 0.017 0.016 

0.120 0.008 0.012 0.009 

0.097 0.008 0.011 0.010 

0.102 0.017 0.018 0.021 

0.067 0.034 0.036 0.037 

0.073 0.008 0.012 0.012 

0.149 0.013 0.021 0.016 

0.128 0.011 0.015 0.016 

0.077 0.105 0.011 0.010 

0.108 0.006 0.010 0.009 

0.084 nd 0.009 0.010 

0.128 0.009 0.016 0.012 

0.083 0.100 0.015 0.012 

0.083 0.010 0.011 0.006 

0.142 0.001 0.010 0.008 

0.075 0.008 0.011 0.090 

0.119 0.011 0.014 0.012 

N 36 36 36 36 15 15 15 15 12 12 12 12 27 25 26 26 

Min 0.310 0.119 0.249 0.241 0.300 0.090 0.260 0.200 0.020 0.008 0.011 0.022 0.025 0.001 0.009 0.006 

Median 0.636 0.184 0.401 0.366 0.581 0.171 0.382 0.332 0.030 0.012 0.018 0.034 0.096 0.010 0.014 0.012 

Max 1.060 0.387 0.565 0.543 0.696 0.370 0.533 0.510 0.057 0.032 0.042 0.067 0.149 0.105 0.036 0.104 

eSD 0.107 0.026 0.041 0.033 0.126 0.022 0.035 0.051 0.011 0.005 0.010 0.020 0.030 0.006 0.004 0.004 

eCV 17 14 10 9 22 13 9 15 35 46 56 58 32 59 25 37 

Npast 30 27 33 35 9 7 8 10 6 12 7 8 25 16 17 20 

Medianpast 0.626 0.194 0.417 0.375 0.572 0.191 0.393 0.323 0.025 0.012 0.018 0.048 0.086 0.010 0.016 0.015 

SDpast 0.083 0.022 0.071 0.063 0.126 0.049 0.026 0.047 0.008 0.006 0.010 0.039 0.029 0.003 0.005 0.005 

NISTa >0.593 >0.159 >0.371 >0.326 0.593 0.159 0.371 0.326 nq nq nq nq 0.105 nq nq nq 

NISTb >0.572 >0.171 >0.356 0.376 0.572 0.171 0.356 0.320 nq nq nq 0.055 >0.106 >0.009 >0.011 nq 

NNIST 2 4 4 4 4 2 2 1 

Mean 0.583 0.165 0.364 0.351 0.583 0.165 0.364 0.323 0.055 0.105 0.009 0.011 0.028 

Srep 0.008 0.025 0.005 0.010 0.014 0.017 0.009 0.000 

Shet 0.022 0.012 0.008 0.007 0.006 0.017 0.005 0.000 

Sanl 0.015 0.009 0.011 0.004 

SNIST 0.024 0.031 0.013 0.017 0.016 0.024 0.011 0.000 

NAV 0.613 0.175 0.384 0.358 0.587 0.170 0.374 0.330 0.030 0.012 0.018 0.045 0.100 0.009 0.013 0.020 

NAU 0.113 0.033 0.066 0.055 0.102 0.022 0.044 0.051 0.011 0.005 0.010 0.029 0.032 0.006 0.006 0.012 

All Lab Report Page 2 / 6 

C3
 
Round Robin XLV Laboratory Results 

All Values in μg/mL 

trans-α-Carotene Total Lycopene trans-Lycopene Total β-Cryptoxanthin 

Lab 251 252 253 254 

FSV-BA 

FSV-BB 

FSV-BBa 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BGa 

FSV-BH
 

FSV-BI
 

FSV-BJ
 

FSV-BK
 

FSV-BL
 

FSV-BM
 

FSV-BN
 

FSV-BO
 

FSV-BP
 

FSV-BQ
 

FSV-BR
 

FSV-BS
 

FSV-BT
 0.080 0.008 0.012 0.013 

FSV-BU 

FSV-BV 

FSV-BW
 

FSV-BX
 

FSV-BZ
 

FSV-CB
 

FSV-CC
 

FSV-CD
 

FSV-CE
 

FSV-CF
 

FSV-CG
 

FSV-CH
 

FSV-CI
 

FSV-CL
 

FSV-CP
 

FSV-CR
 

FSV-CS
 

FSV-CU
 

FSV-CV
 

FSV-CX
 0.060 0.010 0.010 0.020 

FSV-DB 

FSV-DF 

FSV-DH 

FSV-DK 

FSV-DP 

FSV-DR 

FSV-DU 

FSV-EH 

FSV-EM 

FSV-EQ 

FSV-ES 0.102 nq 0.016 0.014 

251 252 253 254 

0.504 0.163 0.230 0.479 

0.535 0.163 0.230 0.525 

0.351 0.129 0.158 0.405 

0.445 0.210 0.298 0.658 

0.467 0.219 0.228 0.620 

0.468 0.153 0.222 0.495 

0.450 0.151 0.193 0.439 

0.399 0.146 0.198 0.494 

0.494 0.163 0.209 0.468 

0.524 0.167 0.241 0.564 

0.294 0.137 0.196 0.368 

0.444 0.138 0.199 0.526 

0.304 0.125 0.165 0.381 

0.438 0.126 0.194 0.572 

0.450 0.150 0.220 0.480 

0.414 0.136 0.193 0.485 

0.464 0.186 0.258 0.508 

0.450 0.280 0.330 0.510 

0.478 0.171 0.232 0.539 

0.423 0.122 0.187 0.350 

0.547 0.169 0.236 0.538 

0.636 0.195 0.311 0.617 

0.467 0.140 0.229 0.581 

0.209 0.081 0.123 0.252 

0.478 0.156 0.229 0.489 

0.477 0.198 0.319 0.743 

0.525 0.190 0.253 0.515 

0.692 0.260 0.429 0.800 

0.726 0.228 0.309 0.786 

0.340 0.109 0.167 0.349 

0.503 0.168 0.231 0.512 

0.251 0.098 0.143 0.302 

251 252 253 254 

0.291 0.086 0.139 0.276 

0.243 0.080 0.146 0.253 

0.284 0.093 0.170 0.296 

0.260 0.101 0.175 0.337 

0.230 0.081 0.126 0.235 

0.188 0.064 0.113 0.189 

0.254 0.103 0.134 0.306 

0.242 0.081 0.145 0.242 

0.248 0.079 0.136 0.262 

0.200 0.060 0.130 0.210 

0.530 0.197 0.330 0.558 

0.332 0.081 0.166 0.366 

0.170 0.050 0.100 0.181 

251 252 253 254 

0.172 0.033 0.044 0.052 

0.194 0.034 0.046 0.052 

0.142 0.025 0.038 0.040 

0.097 0.013 0.025 0.025 

0.162 0.020 0.031 0.037 

0.179 0.032 0.045 0.061 

0.156 0.028 0.044 0.042 

0.167 0.025 0.043 0.044 

0.160 0.020 0.035 0.034 

0.153 0.023 0.034 0.044 

0.073 0.023 0.032 0.042 

0.114 0.031 0.041 0.040 

0.159 0.027 0.040 0.045 

0.191 0.020 0.044 0.079 

0.127 0.015 0.028 0.025 

0.122 0.025 0.034 0.033 

0.135 0.034 0.043 0.044 

>0.128 >0.024 >0.039 >0.038 

0.205 0.038 0.054 0.070 

0.121 0.026 0.053 0.071 

0.143 0.030 0.042 0.047 

0.131 0.022 0.033 0.038 

0.130 0.020 0.040 0.030 

0.148 0.027 0.040 0.041 

0.110 0.016 0.026 0.029 

0.136 0.018 0.031 0.033 

0.190 0.024 0.041 0.038 

0.135 0.024 0.039 0.040 

N 3 2 3 3 32 32 32 32 13 13 13 13 27 27 27 27 

Min 0.060 0.008 0.010 0.013 0.209 0.081 0.123 0.252 0.170 0.050 0.100 0.181 0.073 0.013 0.025 0.025 

Median 0.080 0.009 0.012 0.014 0.466 0.160 0.229 0.509 0.248 0.081 0.139 0.262 0.143 0.025 0.040 0.041 

Max 0.102 0.010 0.016 0.020 0.726 0.280 0.429 0.800 0.530 0.197 0.330 0.558 0.205 0.038 0.054 0.079 

eSD 0.061 0.037 0.037 0.078 0.040 0.010 0.027 0.053 0.027 0.006 0.007 0.008 

eCV 13 23 16 15 16 13 19 20 19 26 18 18 

Npast 0 0 0 0 26 20 19 24 9 0 8 0 25 14 14 18 

Medianpast 0.427 0.135 0.212 0.490 0.286 0.157 0.142 0.035 0.043 0.053 

SDpast 0.102 0.042 0.052 0.139 0.072 0.009 0.032 0.013 0.012 0.012 

NISTa 0.150 0.018 0.037 0.033 

NISTb 0.106 0.009 0.011 nq 0.615 0.181 0.261 0.626 0.241 0.080 0.139 0.262 0.126 0.024 0.033 0.038 

NNIST 2 1 2 1 2 1 2 2 2 2 2 2 4 4 4 4 

Mean 0.106 0.009 0.011 0.018 0.461 0.181 0.261 0.626 0.241 0.080 0.139 0.262 0.138 0.021 0.035 0.036 

Srep 0.005 0.001 0.004 0.000 0.294 0.017 0.035 0.016 0.003 0.002 0.003 0.012 0.003 0.002 0.002 0.003 

Shet 0.001 0.000 0.001 0.000 0.238 0.000 0.014 0.037 0.009 0.003 0.003 0.003 0.003 0.002 0.001 0.003 

Sanl 0.017 0.004 0.003 0.003 

SNIST 0.005 0.001 0.004 0.000 0.378 0.017 0.038 0.040 0.010 0.004 0.004 0.013 0.018 0.005 0.004 0.005 

NAV 0.464 0.172 0.245 0.567 0.245 0.081 0.139 0.262 0.140 0.023 0.037 0.038 

NAU 0.378 0.045 0.061 0.139 0.051 0.017 0.029 0.054 0.033 0.008 0.011 0.011 

All Lab Report Page 3 / 6 

C4
 
Round Robin XLV Laboratory Results 

All Values in μg/mL 

Total α-Cryptoxanthin Total Lutein Total Zeaxanthin Total Lutein&Zeaxanthin 

Lab 251 252 253 254 

FSV-BA
 

FSV-BB
 0.034 0.019 0.018 0.020 

FSV-BBa 0.026 0.016 0.015 0.016 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BGa 

FSV-BH 

FSV-BI 

FSV-BJ 

FSV-BK 

FSV-BL
 

FSV-BM
 

FSV-BN
 0.023 0.012 0.009 0.010 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.029 0.020 0.016 0.024 

FSV-BU 

FSV-BV 

FSV-BW
 

FSV-BX
 

FSV-BZ
 

FSV-CB
 

FSV-CC
 

FSV-CD
 0.050 0.025 0.023 0.029 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CH 

FSV-CI
 

FSV-CL
 0.051 0.018 0.016 0.040 

FSV-CP 

FSV-CR 

FSV-CS 

FSV-CU 

FSV-CV 

FSV-CX 

FSV-DB 

FSV-DF 

FSV-DH 

FSV-DK 

FSV-DP 

FSV-DR 

FSV-DU 

FSV-EH 

FSV-EM 

FSV-EQ 

FSV-ES 

251 252 253 254 

0.578 0.060 0.057 0.089 

0.516 0.056 0.052 0.088 

0.492 0.045 0.047 0.097 

0.445 0.044 0.040 0.075 

0.387 0.036 0.035 0.048 

0.479 0.049 0.046 0.057 

0.358 0.036 0.029 0.059 

0.660 0.056 0.052 0.072 

0.392 0.044 0.040 0.066 

0.333 0.049 0.057 0.062 

0.298 0.034 0.039 0.047 

0.260 0.063 0.058 0.086 

0.041 0.040 0.053 

0.467 0.059 0.058 0.075 

0.350 0.030 0.030 0.040 

0.442 0.039 0.039 0.052 

0.418 0.050 0.046 0.061 

0.432 0.042 0.034 0.052 

251 252 253 254 

0.068 0.021 0.029 0.032 

0.065 0.020 0.025 0.030 

0.063 0.017 0.021 0.021 

0.098 0.010 0.010 0.020 

0.052 0.017 0.027 0.025 

0.056 0.019 0.026 0.022 

0.054 0.012 0.019 0.023 

0.068 0.018 0.026 0.029 

0.048 nq 0.029 0.030 

0.029 0.018 0.024 0.024 

0.068 0.019 0.022 0.026 

0.018 0.026 0.026 

0.050 0.010 0.020 0.020 

0.047 0.013 0.019 0.019 

0.057 0.019 0.026 0.025 

0.050 0.017 0.021 0.023 

251 252 253 254 

0.679 0.079 0.087 0.136 

0.646 0.081 0.086 0.121 

0.581 0.076 0.077 0.118 

0.555 0.062 0.068 0.118 

0.548 0.064 0.055 0.109 

0.439 0.053 0.062 0.073 

0.535 0.068 0.072 0.079 

0.348 0.049 0.045 0.063 

0.390 0.047 0.045 0.067 

0.728 0.074 0.078 0.101 

0.362 0.066 0.081 0.085 

0.364 0.079 0.106 0.134 

0.470 0.069 0.079 0.090 

0.366 0.053 0.061 0.073 

0.536 0.059 0.066 0.079 

0.452 0.066 0.094 0.127 

0.489 0.075 0.091 0.104 

0.296 0.051 0.058 0.075 

0.460 0.068 0.074 0.087 

0.428 0.063 0.076 0.081 

0.400 0.040 0.050 0.060 

0.345 0.057 0.064 0.078 

0.489 0.052 0.058 0.071 

0.475 0.069 0.072 0.086 

0.350 0.045 0.052 0.078 

0.291 0.050 0.059 0.026 

0.482 0.059 0.055 0.075 

N 6 6 6 6 17 18 18 18 15 15 16 16 27 27 27 27 

Min 0.023 0.012 0.009 0.010 0.260 0.030 0.029 0.040 0.029 0.010 0.010 0.019 0.291 0.040 0.045 0.026 

Median 0.032 0.019 0.016 0.022 0.432 0.045 0.043 0.061 0.056 0.018 0.024 0.024 0.460 0.063 0.068 0.081 

Max 0.051 0.025 0.023 0.040 0.660 0.063 0.058 0.097 0.098 0.021 0.029 0.032 0.728 0.081 0.106 0.136 

eSD 0.014 0.002 0.002 0.008 0.090 0.011 0.010 0.017 0.012 0.003 0.004 0.004 0.127 0.012 0.015 0.024 

eCV 46 12 11 36 21 25 22 27 22 17 16 16 28 19 22 30 

Npast 0 0 0 0 11 10 9 14 9 5 15 6 23 6 11 10 

Medianpast 0.397 0.049 0.040 0.073 0.051 0.015 0.026 0.030 0.472 0.066 0.079 0.099 

SDpast 0.041 0.040 0.012 0.045 0.017 0.007 0.002 0.011 0.077 0.006 0.011 0.016 

NISTa 0.518 0.052 0.062 0.068 0.020 nq nq 0.019 0.538 >0.052 >0.062 0.081 

NISTb 0.439 0.054 0.045 0.075 0.070 0.027 0.030 0.047 0.509 0.081 0.075 0.122 

NNIST 4 4 4 4 4 2 2 4 4 2 2 4 

Mean 0.479 0.053 0.054 0.071 0.045 0.027 0.030 0.033 0.523 0.066 0.069 0.102 

Srep 0.014 0.001 0.002 0.003 0.005 0.002 0.002 0.001 0.015 0.002 0.004 0.008 

Shet 0.003 0.001 0.000 0.002 0.000 0.001 0.001 0.001 0.003 0.001 0.000 0.006 

Sanl 0.056 0.001 0.012 0.005 0.035 0.020 0.021 0.029 

SNIST 0.058 0.002 0.012 0.006 0.035 0.002 0.002 0.020 0.026 0.002 0.004 0.031 

NAV 0.455 0.049 0.049 0.066 0.050 0.022 0.027 0.029 0.498 0.065 0.068 0.091 

NAU 0.104 0.013 0.014 0.018 0.036 0.009 0.008 0.021 0.120 0.014 0.015 0.034 

All Lab Report Page 4 / 6 

C5
 
 

Round Robin XLV Laboratory Results 

All Results in μg/mL
 

Analytes Reported By One Laboratory
 

Term 

N 

Min 

Median 

Max 

eSD 

eCV 

Npast 

Medianpast 

SDpast 

NNIST 

Mean 

Srep
 

Shet
 

Sanl
 

SNIST
 

NAV 

NAU 

nd 

nq 

<x 

>x 

italics 

All Lab Report 

Analyte Code 251 252 253 254 

9-cis-β-Carotene FSV-DH 0.016 0.005 0.010 0.022 

13-cis-β-Carotene FSV-DH 0.023 0.013 0.022 0.039 

9-cis-Lycopene FSV-DH 0.070 0.029 0.038 0.105 

13-cis-Lycopene FSV-DH 0.088 0.031 0.056 0.128 

15-cis-Lycopene FSV-DH 0.004 0.003 0.005 0.009 

3-cis-β-Cryptoxanthin FSV-CD 0.128 0.024 0.039 0.038 

Total cis-β-Cryptoxanthin FSV-BT 0.022 0.007 0.009 0.021 

Total Cryptoxanthin FSV-DH 0.264 0.062 0.090 0.096 

Total anhydro-Lutein FSV-BT 0.051 0.024 0.016 0.036 

Coenzyme Q10 FSV-CH 0.367 0.716 0.499 0.511 

Legend 

Definition

 Number of (non-NIST) quantitative values reported for this analyte

 Minimum (non-NIST) quantitative value reported

 Median (non-NIST) quantitative value reported

 Maximum (non-NIST) quantitative value reported

 Standard deviation for (non-NIST) results: 0.741*(3rd Quartile - 1st Quartile)

 Coefficient of Variation for (non-NIST) results: 100*SD/Median

 Mean of N(s) from past RR(s)

 Mean of Median(s) from past RR(s)

 Pooled SD from past RR(s)

 Number of vials analyzed in duplicate by NIST analyst(s)

 Mean of the NIST-analyzed vial means

 W ithin-vial pooled standard deviation

 Among-vial pooled standard deviation

 Between NIST analyst standard deviation 

2

)

0.5 Total standard deviation for NIST analyses: (Srep 2

 + Shet 2 + Sanl 

 NIST Assigned Value

 = (Median + Mean)/2 for analytes reported by NIST analyst(s)
 

= Median for analytes reported by ≥ 10 labs but not NIST

2

)

0.5 NIST Assigned Uncertainty: (S2

 + Sbtw 

 S is the maximum of (0.05*NAV, SD, SNIST, eSD) and Sbtw is the standard

 deviation between Median and Mean. The expected long-term SD, eSD,

 is defined in: Duewer, et al. Anal Chem 1997;69(7):1406-1413.

 Not detected (i.e., no detectable peak for analyte)

 Detected but not quantitatively determined

 Concentration below the limit of quantification, x

 Concentration greater than x

 Not explictly reported but calculated by NIST from reported values 

Page 5 / 6 

C6
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lab 

FSV-BA
 

FSV-BB
 

FSV-BBa
 

FSV-BD
 

FSV-BE
 

FSV-BF
 

FSV-BG
 

FSV-BGa
 

FSV-BH
 

FSV-BI
 

FSV-BJ
 

FSV-BK
 

FSV-BL
 

FSV-BM
 

FSV-BN
 

FSV-BO
 

FSV-BP
 

FSV-BQ
 

FSV-BR
 

FSV-BS
 

FSV-BT
 

FSV-BU
 

FSV-BV
 

FSV-BW
 

FSV-BX
 

FSV-BZ
 

FSV-CB
 

FSV-CC
 

FSV-CD
 

FSV-CE
 

FSV-CF
 

FSV-CG
 

FSV-CH
 

FSV-CI
 

FSV-CL
 

FSV-CP
 

FSV-CR
 

FSV-CS
 

FSV-CU
 

FSV-CV
 

FSV-CX
 

FSV-DB
 

FSV-DF
 

FSV-DH
 

FSV-DK
 

FSV-DP
 

FSV-DR
 

FSV-DU
 

FSV-EH
 

FSV-EM
 

FSV-EQ
 

FSV-ES
 

NISTa 

NISTb 

n 

StS 

1 

2 

3 

4 

Round Robin XLV Laboratory Results 

Comparability Summary 

R aT gT bC tbC aC Ly bX Label Definition 

1 2 1 1 1 

1 1 1 1 2 

2 1 1 2 3 

1 1 2 

1 2 1 3 4 4 

2 2 1 

1 1 1 2 

2 1 1 1 1 1 

2 1 1 1 1 1 

1 1 1 1 

1 1 2 2 2 1 

1 2 2 2 1 2 

2 4 4 4 4 

2 4 

1 2 2 1 1 

1 1 

1 3 4 2 

1 3 

2 2 1 1 

3 2 2 2 4 

4 3 4 1 1 

3 1 3 

2 1 1 1 

1 1 2 4 

1 1 1 2 2 1 

4 1 

2 1 1 1 

3 2 1 2 2 

2 

2 2 

4 1 2 1 1 1 

1 1 

2 1 

2 1 2 3 2 

1 2 4 3 2 

1 2 1 

1 2 4 1 1 

1 

2 1 1 2 1 

1 2 1 2 2 2 

1 1 

1 1 1 1 1 

1 2 

1 1 1 1 1 1 

3 3 4 

2 3 4 

2 3 2 4 

2 2 2 

1 1 1 

2 2 2 

3 

1 2 2 1 

1 1 Lab laboratory number 

1 1 R "Standard Score" for Retinol 

2 aT "Standard Score" for α-Tocopherol 

2 2 gT "Standard Score" for γ-Tocopherol 

3 bC "Standard Score" for Total β-Carotene 

tbC "Standard Score" for trans-β-Carotene 

aC "Standard Score" for Total α-Carotene 

2 Ly "Standard Score" for Total Lycopene 

1 2 bX "Standard Score" for β-Cryptoxanthin 

1 1 n number of laboratories providing data for this analyte 

1 2 

1 1 "Standard Score" 

3 Given that our knowledge of the shape, location, and width of the measurement 

distributions is approximate and that a limited number of labs are involved, we 

1 1 summarize comparability with the following four-level "Standard Score" (StS)... 

2 StS Definition 

1 All StV within ±t (1-0.683,n-1) { ±1 SD} 

3 1 2 All StV within ±t (1-0.954,n-1) { ±2 SD} 

2 3 All StV within ±t (1-0.997,n-1) { ±3 SD} 

1 3 4 At least one StV > ±t (1-0.997,n-1) { >3 SD} 

1 

1 2 where: 

2 2 StV Standardized Value, the distance in standard deviation units your value 

1 1 is from the "true" concentration: StV = (your value - NAV) / NAU 

1 2 

1 1 NAV NIST Assigned Value, our estimate of the "true" analyte concentration 

2 1 

NAU NIST Assigned Uncertainty, our estimate of the total measurement 

standard deviation (serum heterogeniety, analytical repeatibility, 

1 3 and among-laboratory reproducibility) 

t (1-α,n-1) Two-tailed Student's t for coverage of ±1, ±2, and ±3 NAU about 

2 NAV, assuming a normal population of size n 

1 1 

2 4 

1 2 

2 2 

1 

1 1 

2 1 

2 1 

1 2 

1 1 1 1 1 1 

1 1 1 1 1 1 1 

49 48 28 36 15 27 32 27 

% Observed Expected 

51 48 54 47 40 59 56 52 68.2 % These are the observed and normal-population-expected proportions 

33 38 29 39 33 19 34 37 27.3 % of each Standard Score (StS), based upon each laboratory's largest 

10 13 0 8 13 4 9 7 4.3 % StV for the four sera.
 

6 2 18 6 13 19 0 4
 0.3 % 

All Lab Report Page 6 / 6 

C7
 
Appendix D. Representative “Individualized Report” for RR45 

Each participant in RR45 received an “Individualized Report” reflecting their reported 

results. Each report included a detailed analysis of the results they reported for the 

following analytes: 

• Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ-Tocopherol 

• Total β-Carotene 

• trans-β-Carotene 

• Total cis-β-Carotene 

• Total α-Carotene 

• Total Lycopene 

• trans-Lycopene 

• Total β-Cryptoxanthin 

• Total Lutein 

• Total Zeaxanthin 

• Total Lutein & Zeaxanthin 

The following 12 pages are the “Individualized Report” for the analytes evaluated by 

participant FSV-BA. 

D1
 

 Set 1 of 53

Individualized Round Robin XLV Report: FSV-BA 

Summary 

Serum 251 Serum 252 Serum 253 Serum 

Analyte You NAV n You NAV n You NAV n You N

Retinol 0.952 0.910 50 0.394 0.377 50 0.571 0.546 50 1.210 1

Retinyl Palmitate 0.068 0.052 14 0.022 0.022 13 0.065 0.059 15 0.071 0

α-Tocopherol 19.42 20.71 48 5.5 5.4 48 5.6 5.4 48 25.56 26

γ-Tocopherol 1.78 1.63 28 3.32 3.28 28 2.51 2.38 28 5.86 5

Total β-Carotene 0.628 0.613 36 0.193 0.175 36 0.411 0.384 36 0.396 0

trans-β-Carotene 0.602 0.587 15 0.181 0.170 15 0.393 0.374 15 0.374 0

Total cis-β-Carotene 0.026 0.030 12 0.012 0.012 12 0.018 0.018 12 0.022 0

Total α-Carotene 0.076 0.100 27 0.007 0.009 25 0.014 0.013 26 0.012 0

trans-Lycopene 0.291 0.245 13 0.086 0.081 13 0.139 0.139 13 0.276 0

Total β-Cryptoxanthin 0.172 0.140 27 0.033 0.023 27 0.044 0.037 27 0.052 0

Total Lutein&Zeaxanthin 0.679 0.498 27 0.079 0.065 27 0.087 0.068 27 0.136 0

D2

You : Your reported values for the listed analytes (micrograms/milliliter) 

NAV : NIST Assigned Values, equal to (NIST's average-of-averages + this RR's median) / 2 

n : Number of non-NIST laboratories reporting quantitative values for this analyte in this serum 

Please check our records against your records. Send corrections and/or updates to... 

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology Tel: (301) 

100 Bureau Drive Stop 8392 Fax: (301) 

Gaithersburg, MD 20899-8392 USA Email: david.duewer

 Individualized Report 
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

Retinol 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 2 / 12 

D3
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

Retinyl Palmitate Your [Analyte], μg/mL

Apparent Precision, SD 

Apparent Precision, SD [Analyte], μg/mL 

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 3 / 12 

D4
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

α-Tocopherol 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 4 / 12 

D5
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

γ-Tocopherol 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 5 / 12 

D6
 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

Total β-Carotene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 6 / 12 

D7
 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

trans-β-Carotene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 7 / 12 D8
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

Total cis-β-Carotene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 8 / 12 

D9
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

Total α-Carotene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 9 / 12 

D10
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

trans-Lycopene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 10 / 12 

D11
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

Total β-Cryptoxanthin 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 11 / 12 

D12
 

 

 

 

 Set 1 of 53

Individualized RR XLV Report: FSV-BA 

Total Lutein&Zeaxanthin 

[Analyte], μg/mL 

Your [Analyte], μg/mL

242 251 78 163 252 182 185 216 253 193 254 

Serum Median [Analyte], μg/mL 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR NIST, this RR 

Median (50%) 

You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#251 #242 in RR42 (4/98) Potential plasticizer interferent(s) 

#252 #78 in RR12 (4/88), #163 in RR24 (4/92) Originally issued as “Control D” 

#253 #182&185 in RR28 (6/93), #216 in RR36 (3/96) 

#254 #193 in RR30 (3/94) 

 Individualized Report Page 12 / 12 

D13
Appendix E. Shipping Package Inserts for RR46 

The following three items were included in each package shipped to an RR46 participant: 

• Cover letter 

• Datasheet 

The cover letter and datasheet were enclosed in a sealed waterproof bag along with the 

samples themselves. 

E1
June 14, 1999 

. :-- Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed is the set of samples for the second quality assurance round robin exercise (Round 

Ro bin XL VI) for FY 99. You will find one vial of each of four lyophilized serum samples for 

analysis along with a form for reporting your results. When reporting your results, please submit 

one value for each analyte for a given serum sample. If an obtained value is below your limit of 

quantitation, please indicate this result on the form by using NQ (Not Quantitated). For analytes 

. not measured, please leave a blank. Results are due to NIST by September 10, 1999. Results 

received two weeks after the due date will not be included in the summary report for this round 

robin study. The feedback report concenμn.g the study will be provided around the first week of 

October. 

Samples should be reconstituted with 1.0 rnL ofHPLC-grade water or equivalent. We 

recommend that dissolution be facilitated with 3 to 5 min agitation in an ultrasonic bath or at 

least 30 min at room temperature with intermittent swirling. (CAUTION: Vigorous shaking will 

cause foaming and possibly interfere with accurate measurement. The rubber stopper contains 

phthalate esters that will leach into the sample upon intermittent contact of the liquid sample with 

the stopper. These esters absorb strongly in the UV region and elute very near retinol in most LC 

systems creating an~ytical problems.) Pipette a known volume of serum from the vial for 

analysis. (The final volume of the reconstituted sample is greater than 1.0 rnL.). For consistency, 

we request that laboratories use the following absorptivities (E 1 % cm) in ethanol: retinol, 1843 

at 325 nm; retinyl palmitate, 975 at 325 nm; o:-tocopherol, 75.8 at 292 nm; y-tocopherol, 91.4 at 

298 nm; a-carotene, 2800 at 444 nm (in hexane); P-carotene, 2560 at 450 nm (in ethanol), 2592 

at 452 nm (in hexane); lycopene, 3450 at 472 nm (in hexane). 

Please mail or fax your results for Round Robin XL VI to: 

Micronutrients Measurement Quality Assurance Program . 

NIST 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 

Fax: (301) 977-0685 

If you have questions regarding this round robin exercise, please call me at (301) 97 5-3120; 

-... e-mail me at jbthomas@ni .gov; or mail/fax queries to the ab.ove address. 

J aruce Brown Thomas 

search Chemist 

alytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

cc: L. C. Sander N•Si 

E2
 

 

 

NIST 

Micronutrients Measurement Quality Assurance Program 

Round Robin XLVI Results from Laboratory #_____ 

Serum 

Analyte 255 256 257 258 Units* 

total retinol 

trans-retinol 

retinyl palmitate 

α-tocopherol 

γ-tocopherol 

δ-tocopherol 

total β-carotene 

trans-β-carotene 

total cis-β-carotene 

total α-carotene 

trans-α-carotene 

total lycopene 

trans-lycopene 

total β-cryptoxanthin 

total α-cryptoxanthin 

total lutein 

total zeaxanthin 

total lutein&zeaxanthin 

Other Analytes? 

* We prefer μg/mL 

Today's Date: 

Comments? 

Mail: M2QAP 

NIST, Stop 8392 Please return results on-or-before Fax: 301-977-0685 

Gaithersburg, MD 20899-8392 10-Sep-99 Email: David.Duewer@NIST.gov 

E3
 

 

Appendix F. Final Report for RR46 

The following three pages are the final report as provided to all participants: 

•	 Cover letter 

•	 An information sheet that: 

o	 describes the contents of the “All-Lab” report 

o	 describes the content of the “Individualized” report 

o	 describes the nature of the test samples and details any previous distributions 

o	 summarizes aspects of the study that we believe may be of interest to the 

participants 

F1
October 22, 1999 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed is the summary report of the results for Round Robin XL VI (RR 46). Included in this 

report are: a summary of data for all laboratories; the measurement comparability summary for 

evaluating laboratory performance; a summary of individual laboratory performance and 

interlaboratory accuracy and precision; and a summary of the NIST assigned value (NAV) vs. your 

laboratory value for the analytes measured. As in previous.teports, the NIST assigned values are 

derived from the equally weighted means of the medians from this interlaboratory comparison 

exercise and the means from the analyses performed by NIST. 

Data for evaluating laboratory performance in RR 46 are provided in the comparability summary 

(Score Card) on page 6 of the "All Lab Report." Laboratory comparability is summarized as 

follows: results rated 1 to 3 are within 1 to 3 standard deviation(s) of the assigned value; those rated 

4 are >3 standard deviations from the assigned value. 

If you have concerns regarding your laboratory performance, we suggest that you obtain and analyze 

a unit of SRM 968c, Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum, when it 

becomes available. If your measured values do not agree with the certified values, we suggest that 

you contact us for consultation. 

We are in the process of evaluating the QA program for FY 2000 and will inform you in a 

forthcoming letter of the decision regarding its continuance. If it is decided that the program will 

continue through FY 2000, an Intent-to-Participate form, which will provide us with formal 

notification of your intent to participate in the program for the upcoming year, will be mailed to you. 

If you have any questions regarding this report, please .contact me at 301/975-3120; fax: 301/977-

0685; or e-mail: jeanice.brownthomas@nist.gov. 

esearch Chemist 

Analytical Chemistry Division . 

Chemical Science and Technqlogy Laboratory 

cc: L. C. Sander 

Enclosures 

F2
 

 

The NIST M2QAP Round Robin XLVI (RR46) report includes: 

Page “All Lab” Report 

1-4 A listing of all results and statistics for analytes reported by at least two laboratories 

5 A list of results for the analytes reported by only one laboratory and a legend for the 

above two lists 

6 The “Measurement Comparability Summary” (or “Score Card”) 

Page “Individualized” Report 

1 Your values, the number of labs reporting values, and our assigned values. 

2+ “Four Plot” summaries of your current and past measurement performance, one page 

for each analyte you report that is also reported by at least 6 other participants. 

See Anal Chem 1999; 71:1074-9 for details of the design and interpretation of the “Four Plot” 

graphics. 

Samples. Four sera from previous Round Robin exercises were distributed in RR46. The sera were 

selected from our -80 oC archives to: 1) confirm analyte stability in our SRM 968c sera and 

2) further explore “total retinol” vs. “trans-retinol” issues with a serum believed to have a very high 

trans-retinol level and a Report data sheet that separately lists the two measurands. 

Serum #255 is a medium-to-high-analyte level augmented serum, previously distributed as #193 

(RR30,3/94) and #254 (RR45,3/99). Approximately 30% of the total retinol in this serum is a 

mixture of cis-retinol isomers. 

Serum #256 is Level II of SRM 968c, previously distributed as #249 (RR44,10/98). This material is 

a blended serum with native carotenoid levels and augmented levels of α- and δ-tocopherol. 

Serum #257 is native serum, previously distributed as #171 (RR26,10/92) and as #176 (RR27,3/93). 

Serum #258 is Level I of SRM 968c, previously distributed as #249 (RR44,10/98). This material is 

a blended serum with native carotenoid levels and augmented levels of retinol and γ-tocopherol. 

Qualitative Results. 

1) One participant noted that sera #255 and #258 “yielded extremely dense suspensions quite unlike 

a normal serum sample; they had the appearance of ... samples which have been repeatedly 

sampled and refrozen over an extended period of time”. Since these two sera are quite unrelated 

and of very different vintage and this was the only comment of this nature, we do not believe this 

indicates a general problem. However, whenever one of the M2

QAP samples is “odd”, please 

note the particulars on the report sheet or in a cover letter! 

2) Analyst NISTb changed from a C18 to a C30 column for all M2

QAP analyses in this exercise. To 

our distress, both sera #256 and #258 contain presumptively plasticizers that fluoresce at λex 295 

nm, λem 335 nm On retrospective examination of the chromatograms from last year’s analysis of 

these materials, these compounds elute on C18 columns well before the tocopherols. Since the 

distributions of the RR44 and RR46 tocopherol data for these two sera are quite routine, we 

believe these compounds are tocopherol interferents only with the C30 column and perhaps only 

when using fluorescence detection. 

F3
 

Quantitative Results 

1)	 The only noted interference artifact is discussed above. 

2)	 There is no evidence for any analyte that any of the four sera have significantly degraded in 

storage, either in change of medians or in increased interlaboratory variability. 

3)	 Note that serum #255 is a repeat of RR45’s #254. We believe that this serum contains about 

70% trans- and 30% cis-retinol. Examination of your data in the summary box plot for “total 

retinol” may help you evaluate whether what you report is what you are actually measuring. If 

you report “total retinol”, your values should be in about the same location relative to the 

interlaboratory median for all four sera. If your data for sera #254 and #255 are relatively lower 

than the other three sera, you may not be accounting for the cis-retinol isomers. If you report 

trans-retinol, the relative location of your values for #254 and #255 (plotted as triangles, 

signifying “>x” values for total retinol) should be relatively lower than the other three. If your 

values for this material are too concordant with the other sera, you are not resolving the isomers. 

For those of you who are interested in the mathematics of analytical calibration – hopefully, at least 

all of you who “do your own” rather than using procedures built-in to commercial chromatographic 

software systems – we strongly encourage you to read: “Guidelines for Calibration in Analytical 

Chemistry. Part 1. Fundamentals and Single Component Calibration”, Klaus Danzer and Lloyd A. 

Currie (Analytical Chemistry Division, Commission on General Aspects of Analytical Chemistry, 

IUPAC), Pure & Applied Chemistry, Vol. 70 No. 4, pp. 993-1014, 1998. This article clearly 

presents the appropriate nomenclature, implementation equations, and summary statistics for a 

number of different calibration models. 

F4
 

Appendix G. “All-Lab Report” for RR46 

The following six pages are the “All-Lab Report” as provided to all participants, with two 

exceptions: 

• the participant identifiers (Lab) have been altered. 

• the order in which the participant results are listed has been altered. 

The data summary in the “All-Lab Report” has been altered to ensure confidentiality of 

identification codes assigned to laboratories. The only attributed results are those 

reported by NIST. The NIST results are not used in the assessment of the consensus 

summary results of the study. 

G1
Round Robin XLVI Laboratory Results 

All values in μg/mL 

Lab 255 

Total Retinol 

256 257 

trans-Retinol Retinyl Palmitate 

258 

α-Tocopherol γ-Tocopherol 

FSV-BA 1.089 0.467 0.504 0.787 

FSV-BB 1.152 0.473 0.525 0.848 

FSV-BD 1.033 0.456 0.813 

FSV-BE 1.049 0.462 0.528 0.835 

FSV-BF 1.030 0.515 0.525 0.905 

FSV-BG 1.049 0.455 0.512 0.804 

FSV-BGa 1.081 0.461 0.509 0.825 

FSV-BH 0.871 0.460 0.520 0.772 

FSV-BI 1.071 0.477 0.542 0.851 

FSV-BJ 1.096 0.491 0.533 0.832 

FSV-BK >1.190 >0.521 >0.575 >0.903 

FSV-BL 0.830 0.430 0.520 0.800 

FSV-BM 1.000 0.510 0.568 0.900 

FSV-BN 1.048 0.459 0.540 0.847 

FSV-BO 0.980 0.458 0.533 0.845 

FSV-BP 0.934 0.445 0.508 0.769 

FSV-BQ 1.021 0.501 0.536 0.985 

FSV-BR >1.20 >0.53 >0.58 >1.09 

FSV-BS 0.840 0.772 0.820 1.309 

FSV-BT 1.106 0.428 0.624 1.093 

FSV-BU 1.061 0.471 0.562 0.845 

FSV-BV 0.698 0.352 0.387 0.686 

FSV-BW 1.133 0.498 0.550 0.830 

FSV-BX 1.080 0.471 0.574 0.887 

FSV-BZ 

FSV-CB 1.032 0.480 0.571 0.868 

FSV-CC 1.100 0.550 >0.55 0.910 

FSV-CD 1.029 0.514 0.543 0.902 

FSV-CE 1.058 0.477 0.537 0.829 

FSV-CF 0.976 0.500 0.555 0.850 

FSV-CG 1.037 0.553 0.542 0.907 

FSV-CH 1.009 0.429 0.492 0.793 

FSV-CI 0.730 0.600 0.720 0.890 

FSV-CK 1.074 0.504 0.630 1.031 

FSV-CL 0.975 0.453 0.541 0.804 

FSV-CN 1.063 0.484 0.554 0.969 

FSV-CR 1.130 0.470 0.500 0.850 

FSV-CS 1.007 0.579 0.665 1.063 

FSV-CT 1.069 0.482 0.528 0.803 

FSV-CV 0.597 0.557 0.550 0.735 

FSV-CX >0.44 >0.44 >0.51 >0.76 

FSV-DB 1.165 0.499 0.539 0.881 

FSV-DD 1.093 0.476 0.523 0.799 

FSV-DF 1.005 0.441 0.492 0.797 

FSV-DH 0.950 0.380 0.470 0.720 

FSV-DK 1.090 0.440 0.510 0.840 

FSV-DP >0.971 >0.485 >0.534 >0.842 

FSV-DR 1.040 0.435 0.490 0.830 

FSV-DU 1.540 0.480 0.610 1.010 

FSV-EH 0.906 0.418 0.519 0.792 

FSV-EM 1.200 0.530 0.770 0.860 

FSV-EQ 1.016 0.481 0.610 0.811 

FSV-ES >0.898 >0.465 >0.516 >0.813 

FSV-FG 0.830 0.490 0.550 0.880 

255 256 257 258 

1.190 0.521 0.575 0.903 

1.200 0.530 0.580 1.090 

1.000 0.520 0.550 0.830 

0.440 0.440 0.510 0.760 

1.005 0.441 0.492 0.797 

0.971 0.485 0.534 0.842 

0.898 0.465 0.516 0.813 

255 256 257 258 

0.076 0.125 0.186 0.058 

0.051 0.070 0.161 0.031 

0.051 0.074 0.070 0.097 

0.023 0.105 0.166 0.048 

0.028 0.088 0.171 0.041 

nq 0.066 0.191 nq 

nd 0.110 0.230 0.042 

nq 0.076 0.212 nq 

0.019 0.073 0.220 0.030 

0.018 0.087 0.176 0.020 

nd 0.113 0.245 0.043 

0.046 0.104 0.122 0.042 

0.070 0.080 0.180 0.030 

0.007 0.079 0.163 0.022 

0.011 0.034 0.065 0.015 

0.038 0.074 0.135 0.042 

255 256 257 258 

28.12 17.89 5.23 7.50 

27.34 17.28 4.92 7.66 

26.50 15.90 7.90 

26.99 17.67 5.26 7.89 

27.35 16.55 4.70 7.60 

28.37 17.51 4.94 7.98 

28.40 16.73 4.89 7.60 

26.24 16.64 4.75 7.38 

28.62 16.55 4.99 7.44 

28.77 17.71 5.05 7.81 

27.30 16.90 5.00 7.40 

27.56 15.94 5.17 7.75 

29.20 16.40 4.90 7.32 

28.25 17.69 5.05 7.99 

26.30 16.28 5.00 7.58 

25.94 16.52 5.25 7.29 

25.24 15.31 4.52 7.73 

21.09 11.39 3.57 4.73 

27.19 16.99 6.07 8.45 

23.30 14.77 4.10 6.78 

27.00 17.16 4.76 7.37 

26.44 16.56 5.07 7.74 

24.10 13.00 4.10 6.10 

24.92 15.54 5.82 7.39 

27.70 17.24 4.85 7.09 

27.06 16.58 4.94 7.23 

28.47 17.24 4.88 7.29 

28.90 18.10 5.50 8.30 

25.54 16.59 4.79 7.45 

25.73 16.05 5.52 8.05 

28.00 15.10 4.40 5.20 

26.75 17.06 5.34 8.74 

34.40 22.70 7.14 10.51 

27.78 17.54 5.07 8.75 

30.50 18.00 4.80 7.80 

29.31 17.65 5.03 8.67 

28.36 17.91 6.22 8.72 

16.16 18.77 4.99 6.57 

26.46 16.59 4.89 7.45 

28.05 17.14 4.82 7.63 

23.15 12.72 4.14 4.25 

24.98 14.84 3.79 5.87 

27.86 16.38 4.48 7.01 

38.10 26.40 8.53 11.60 

38.02 21.42 5.47 8.41 

24.76 16.75 5.19 6.29 

22.24 13.82 4.20 6.34 

22.07 14.88 4.54 6.90 

21.70 14.10 3.60 5.60 

255 256 257 258 

5.81 1.53 1.96 3.54 

5.65 1.45 1.88 3.59 

6.26 1.38 2.04 3.92 

5.87 1.55 1.96 3.82 

6.16 1.60 2.05 3.87 

5.41 1.57 2.02 3.46 

6.42 1.74 2.20 4.13 

6.20 1.46 1.96 3.80 

6.46 1.67 2.06 3.98 

5.65 1.47 1.81 3.63 

5.15 1.90 1.58 2.75 

5.57 2.00 2.34 3.70 

5.57 1.41 1.88 3.86 

6.11 1.60 2.06 3.73 

5.88 1.58 2.16 3.92 

4.00 1.70 1.80 3.80 

5.93 1.47 1.95 3.76 

6.04 1.84 2.12 4.14 

5.27 1.33 1.69 3.34 

6.50 1.50 2.00 2.90 

6.46 1.67 2.46 4.96 

7.32 2.17 2.63 4.64 

6.03 1.54 2.05 4.40 

6.48 1.59 2.02 4.22 

3.39 1.63 2.01 3.25 

5.77 1.40 1.94 3.72 

4.28 0.96 1.42 2.77 

5.55 1.34 1.54 2.98 

4.81 1.24 1.47 2.87 

N 48 48 46 48 7 7 7 7 12 16 16 14 49 49 48 49 29 29 29 29 

Min 0.597 0.352 0.387 0.686 0.440 0.440 0.492 0.760 0.007 0.034 0.065 0.015 16.2 11.4 3.6 4.3 3.4 1.0 1.4 2.7 

Median 1.039 0.477 0.538 0.845 1.000 0.485 0.534 0.830 0.033 0.080 0.173 0.042 27.2 16.6 4.9 7.5 5.9 1.6 2.0 3.8 

Max 1.540 0.772 0.820 1.309 1.200 0.530 0.580 1.090 0.076 0.125 0.245 0.097 38.1 26.4 8.5 11.6 7.3 2.2 2.6 5.0 

eSD 0.077 0.033 0.030 0.066 0.121 0.050 0.037 0.050 0.024 0.023 0.031 0.009 2.1 1.2 0.3 0.6 0.5 0.2 0.1 0.3 

eCV 7 7 6 8 12 10 7 6 73 28 18 22 8 7 7 8 8 10 7 9 

Npas t 47 46 40 46 0 0 0 0 10 15 9 13 46 46 39 46 24 23 14 23 

Medianpas t 1.047 0.481 0.541 0.853 0.045 0.083 0.192 0.030 26.72 16.63 4.93 7.40 6.11 1.61 2.11 3.90 

SDpas t 0.106 0.043 0.043 0.047 0.047 0.021 0.028 0.013 2.22 1.46 0.49 0.84 0.59 0.12 0.25 0.32 

NISTa 0.984 >0.500 >0.585 0.905 0.840 0.500 0.585 0.867 27.83 17.50 4.87 7.53 6.32 1.54 2.05 3.98 

NISTb >0.913 >0.466 >0.537 >0.815 0.913 0.466 0.537 0.815 29.90 5.27 6.05 1.98 

NNIST 6 6 6 6 6 6 6 6 6 3 6 3 6 3 6 3 

MeanNIST 0.941 0.483 0.561 0.858 0.876 0.483 0.561 0.839 28.79 17.50 5.08 7.53 6.16 1.55 2.02 3.98 

Sr ep 0.017 0.007 0.011 0.025 0.047 0.007 0.011 0.022 0.24 0.23 0.13 0.08 0.06 0.02 0.07 0.07 

Shet 0.058 0.005 0.007 0.019 0.073 0.005 0.007 0.017 0.49 0.15 0.15 0.08 0.11 0.03 0.04 0.05 

Sanl 0.058 0.025 0.034 0.067 0.034 0.025 0.034 0.040 1.42 0.26 0.18 0.05 

SNIST 0.084 0.026 0.037 0.074 0.093 0.026 0.037 0.048 1.52 0.27 0.33 0.12 0.22 0.04 0.10 0.09 

NAV 0.990 0.480 0.549 0.851 0.938 0.484 0.547 0.835 0.033 0.080 0.173 0.042 27.99 17.07 5.01 7.51 6.01 1.55 2.01 3.87 

NAU 0.109 0.039 0.046 0.074 0.150 0.050 0.047 0.065 0.024 0.025 0.043 0.019 2.48 1.43 0.49 0.62 0.53 0.17 0.21 0.38 

All Lab R epor t P age 1 / 6 

G2
Round Robin XLVI Laboratory Results 

All values in μg/mL 

Lab 

δ-Tocopherol Total β-Carotene trans-β-Carotene 

255 256 257 258 

Total cis-β-Carotene 

FSV-BA 

FSV-BB 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BGa 

FSV-BH
 

FSV-BI
 

FSV-BJ
 

FSV-BK
 

FSV-BL
 

FSV-BM
 

FSV-BN
 0.722 0.904 0.171 0.096 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.386 1.962 0.175 0.220 

FSV-BU 

FSV-BV 

FSV-BW
 

FSV-BX
 

FSV-BZ
 

FSV-CB
 

FSV-CC
 

FSV-CD
 

FSV-CE
 

FSV-CF
 

FSV-CG
 1.043 1.244 0.575 0.633 

FSV-CH 

FSV-CI
 

FSV-CK
 

FSV-CL
 

FSV-CN
 

FSV-CR
 0.700 0.700 0.300 <0.3 

FSV-CS 

FSV-CT 

FSV-CV 

FSV-CX 0.400 0.580 0.120 0.130 

FSV-DB 

FSV-DD 

FSV-DF 

FSV-DH 

FSV-DK 

FSV-DP 

FSV-DR 

FSV-DU 

FSV-EH 0.246 0.391 0.085 0.129 

FSV-EM 

FSV-EQ 

FSV-ES 

FSV-FG 

255 256 257 258 

0.399 0.488 0.411 0.186 

0.334 0.413 0.377 0.167 

0.322 0.341 0.318 0.151 

0.367 0.389 0.375 0.187 

0.396 0.497 0.428 0.206 

0.377 0.465 0.395 0.196 

0.366 0.439 0.384 0.156 

0.383 0.433 0.393 0.184 

0.428 0.480 0.435 0.171 

0.368 0.436 0.391 0.190 

0.327 0.383 0.323 0.158 

0.247 0.347 0.295 0.140 

0.289 0.308 0.294 0.139 

0.273 0.356 0.370 0.186 

0.408 0.474 0.426 0.203 

0.410 0.440 0.370 0.165 

0.351 0.480 0.392 0.213 

0.430 0.483 0.429 0.208 

0.387 0.439 0.347 0.180 

0.361 0.449 0.351 0.169 

0.403 0.490 0.412 0.192 

0.356 0.418 0.372 0.175 

0.483 0.521 0.456 0.166 

0.347 0.410 0.360 0.151 

>0.346 >0.427 >0.375 >0.197 

0.387 0.432 0.402 0.200 

0.327 0.450 0.318 0.170 

0.197 0.440 0.385 0.147 

0.348 0.424 0.354 0.158 

>0.395 >0.410 >0.397 >0.183 

0.383 0.489 0.415 0.188 

0.348 0.426 0.312 0.167 

0.390 0.350 0.300 0.160 

0.366 0.448 0.431 0.224 

0.302 0.402 0.368 0.165 

0.436 0.418 0.407 0.161 

>0.289 >0.389 >0.337 >0.171 

255 256 257 258 

0.362 0.453 0.382 0.173 

0.311 0.393 0.354 0.157 

0.337 0.411 0.353 0.156 

0.321 0.406 0.346 0.164 

0.311 0.368 0.311 0.153 

0.264 0.283 0.275 0.132 

0.312 0.426 0.370 0.182 

0.320 0.450 0.380 0.200 

0.355 0.452 0.378 0.177 

0.346 0.427 0.375 0.197 

0.345 0.387 0.363 0.187 

0.280 0.340 0.300 0.150 

0.353 0.380 0.369 0.166 

0.340 0.420 0.398 0.203 

0.289 0.389 0.337 0.171 

255 256 257 258 

0.037 0.034 0.029 0.013 

0.024 0.020 0.023 0.010 

0.029 0.028 0.031 nq 

0.038 0.020 0.035 0.017 

0.016 0.016 0.012 0.005 

0.025 0.025 0.020 0.007 

0.031 0.030 0.012 0.013 

0.048 0.038 0.034 0.015 

0.042 0.045 0.039 0.013 

>0.042 >0.030 >0.028 >0.017 

0.026 0.028 0.033 0.021 

N 6 6 6 5 34 34 34 34 15 15 15 15 10 10 10 9 

Min 0.246 0.391 0.085 0.096 0.197 0.308 0.294 0.139 0.264 0.283 0.275 0.132 0.016 0.016 0.012 0.005 

Median 0.550 0.802 0.173 0.130 0.367 0.438 0.381 0.171 0.321 0.406 0.363 0.171 0.030 0.028 0.030 0.013 

Max 1.043 1.962 0.575 0.633 0.483 0.521 0.456 0.224 0.362 0.453 0.398 0.203 0.048 0.045 0.039 0.021 

eSD 0.243 0.407 0.101 0.067 0.042 0.045 0.043 0.022 0.026 0.032 0.026 0.021 0.009 0.009 0.010 0.004 

eCV 44 51 58 52 12 10 11 13 8 8 7 12 30 31 33 29 

Npas t 0 0 0 0 36 31 34 31 13 14 0 14 10 10 0 9 

Medianpas t 0.370 0.411 0.402 0.176 0.327 0.371 0.158 0.041 0.033 0.015 

SDpas t 0.050 0.051 0.068 0.022 0.049 0.025 0.012 0.031 0.012 0.005 

NISTa 0.346 0.534 nq 0.140 0.369 0.411 0.340 0.171 0.344 0.405 0.336 0.168 0.025 0.006 0.003 0.003 

NISTb 0.463 0.148 >0.362 >0.442 >0.380 >0.179 0.362 0.442 0.380 0.179 

NNIST 6 3 3 3 3 3 3 3 6 6 6 6 

MeanNIST 0.347 0.534 0.148 0.140 0.368 0.411 0.340 0.170 0.355 0.424 0.358 0.173 

Sr ep 0.148 0.020 0.006 0.000 0.006 0.012 0.005 0.004 0.016 0.010 0.009 0.004 

Shet 0.064 0.010 0.006 0.004 0.013 0.016 0.013 0.003 0.010 0.010 0.016 0.002 

Sanl 0.164 0.011 0.026 0.031 0.008 

SNIST 0.229 0.022 0.009 0.004 0.015 0.020 0.014 0.005 0.022 0.030 0.036 0.009 

NAV 0.448 0.668 0.160 0.135 0.367 0.424 0.360 0.170 0.338 0.415 0.361 0.172 0.030 0.028 0.030 0.013 

NAU 0.282 0.449 0.102 0.068 0.052 0.064 0.061 0.027 0.042 0.045 0.039 0.021 0.011 0.010 0.011 0.005 

All Lab R epor t P age 2 / 6 

G3
Round Robin XLVI Laboratory Results 

All values in μg/mL 

Lab 

Total α-Carotene 

255 256 257 258 

trans-α-Carotene Total Lycopene trans-Lycopene Total β-Cryptoxanthin 

FSV-BA 0.008 0.095 0.011 0.010 

FSV-BB 0.014 0.087 0.011 0.013 

FSV-BD 

FSV-BE 

FSV-BF 0.013 0.117 0.011 0.016 

FSV-BG 0.023 0.114 0.022 0.029 

FSV-BGa 0.028 0.087 0.015 0.021 

FSV-BH 0.011 0.101 0.016 0.011 

FSV-BI 0.013 0.098 0.015 0.018 

FSV-BJ nq 0.120 nq nq 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.004 0.086 0.009 0.007 

FSV-BO 0.014 0.132 0.017 0.019 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 0.045 0.078 0.043 0.040 

FSV-BT 0.011 0.070 0.010 0.015 

FSV-BU 0.014 0.088 0.016 0.023 

FSV-BV 0.008 0.080 0.009 0.011 

FSV-BW 0.012 0.107 0.013 0.015 

FSV-BX 0.023 0.096 0.024 0.028 

FSV-BZ 0.020 0.044 0.023 0.022 

FSV-CB 0.011 0.099 0.012 0.013 

FSV-CC 

FSV-CD 0.007 0.150 0.014 0.018 

FSV-CE 

FSV-CF 

FSV-CG 0.015 0.112 0.015 0.016 

FSV-CH 0.021 0.092 0.021 0.015 

FSV-CI 

FSV-CK 0.252 0.123 0.027 0.021 

FSV-CL 0.014 0.146 0.017 0.016 

FSV-CN 0.011 0.097 0.011 0.018 

FSV-CR 

FSV-CS 0.013 0.120 0.014 0.018 

FSV-CT 

FSV-CV 

FSV-CX >0.02 >0.08 >0.01 >0.02 

FSV-DB 

FSV-DD 

FSV-DF 

FSV-DH 0.017 0.108 0.019 0.019 

FSV-DK 0.009 0.100 0.017 0.019 

FSV-DP 

FSV-DR 

FSV-DU 

FSV-EH 0.007 0.143 0.010 0.007 

FSV-EM 0.013 0.085 0.014 0.011 

FSV-EQ 0.015 0.107 0.016 0.015 

FSV-ES >0.012 >0.104 >0.014 >0.018 

FSV-FG 

255 256 257 258 

0.020 0.080 0.010 0.020 

0.012 0.104 0.014 0.018 

255 256 257 258 

0.456 0.386 0.182 0.295 

0.577 0.450 0.182 0.357 

0.526 0.396 0.181 0.312 

0.561 0.435 0.175 0.327 

0.521 0.434 0.183 0.322 

0.469 0.371 0.162 0.286 

0.547 0.454 0.191 0.342 

0.528 0.409 0.200 0.328 

0.789 0.634 0.258 0.478 

0.417 0.382 0.293 0.300 

0.368 0.284 0.125 0.238 

0.293 0.256 0.071 0.249 

0.467 0.383 0.161 0.306 

0.570 0.438 0.173 0.290 

0.499 0.414 0.177 0.310 

0.435 0.383 0.172 0.270 

0.535 0.448 0.189 0.323 

0.406 0.312 0.150 0.244 

0.472 0.370 0.150 0.188 

0.547 0.460 0.183 0.314 

0.555 0.480 0.211 0.415 

0.494 0.397 0.180 0.330 

0.318 0.596 0.271 0.363 

0.591 0.470 0.202 0.368 

0.744 0.634 0.270 0.525 

0.373 0.327 0.177 0.256 

0.529 0.409 0.174 0.276 

0.309 0.290 0.120 0.229 

255 256 257 258 

0.289 0.244 0.114 0.185 

0.227 0.192 0.095 0.147 

0.270 0.210 0.101 0.168 

0.255 0.199 0.098 0.159 

0.127 0.119 0.067 0.087 

0.302 0.227 0.106 0.194 

0.228 0.207 0.108 0.166 

0.370 0.370 0.230 0.300 

0.259 0.218 0.101 0.161 

0.265 0.269 0.127 0.164 

0.200 0.180 0.090 0.140 

0.170 0.122 0.061 0.098 

0.364 0.304 0.138 0.261 

0.192 0.178 0.082 0.143 

255 256 257 258 

0.030 0.026 0.030 0.085 

0.038 0.031 0.032 0.071 

0.032 0.023 0.022 0.066 

0.039 0.037 0.036 0.084 

0.053 0.046 0.042 0.091 

0.043 0.035 0.042 0.093 

0.042 0.030 0.036 0.095 

0.025 0.016 0.019 0.075 

0.031 0.024 0.027 0.065 

0.028 0.026 0.030 0.049 

0.066 0.057 0.044 0.095 

0.012 0.011 0.017 0.070 

0.021 0.014 0.016 0.053 

0.031 0.030 0.028 0.070 

0.030 0.024 0.024 0.062 

0.029 0.027 0.024 0.051 

0.043 0.037 0.029 0.067 

0.039 0.036 0.032 0.023 

0.033 0.028 0.029 0.066 

0.042 0.034 0.036 0.086 

0.044 0.034 0.033 0.082 

0.048 0.048 0.039 0.080 

0.040 0.030 0.030 0.070 

0.038 0.030 0.034 0.081 

0.038 0.033 0.029 0.068 

0.033 0.028 0.031 0.070 

0.064 0.037 0.028 0.096 

0.029 0.027 0.029 0.066 

N 29 30 29 29 2 2 2 2 28 28 28 28 14 14 14 14 28 28 28 28 

Min 0.004 0.044 0.009 0.007 0.012 0.080 0.010 0.018 0.293 0.256 0.071 0.188 0.127 0.119 0.061 0.087 0.012 0.011 0.016 0.023 

Median 0.013 0.099 0.015 0.016 0.016 0.092 0.012 0.019 0.510 0.409 0.181 0.311 0.257 0.209 0.101 0.162 0.038 0.030 0.030 0.070 

Max 0.252 0.150 0.043 0.040 0.020 0.104 0.014 0.020 0.789 0.634 0.293 0.525 0.370 0.370 0.230 0.300 0.066 0.057 0.044 0.096 

eSD 0.005 0.022 0.004 0.004 0.088 0.053 0.018 0.043 0.058 0.042 0.016 0.027 0.009 0.007 0.005 0.014 

eCV 37 22 29 27 17 13 10 14 22 20 16 17 24 23 17 19 

Npas t 23 26 17 26 0 0 0 0 28 25 18 25 13 12 0 12 23 27 10 27 

Medianpas t 0.013 0.091 0.014 0.016 0.499 0.398 0.170 0.314 0.262 0.203 0.152 0.047 0.032 0.047 0.078 

SDpas t 0.005 0.024 0.004 0.004 0.112 0.094 0.046 0.075 0.053 0.040 0.034 0.010 0.008 0.016 0.009 

NISTa >0.031 >0.116 >0.021 >0.022 0.031 0.116 0.021 0.022 0.038 0.034 0.029 0.066 

NISTb >0.015 >0.085 >0.014 >0.013 0.015 0.085 0.014 0.013 0.560 0.448 0.199 0.316 0.172 0.145 0.077 0.105 0.035 0.026 0.030 0.066 

NNIST 6 6 6 6 6 6 6 6 3 3 3 3 3 3 3 3 6 6 6 6 

MeanNIST 0.023 0.101 0.018 0.017 0.023 0.101 0.018 0.017 0.562 0.448 0.198 0.313 0.173 0.145 0.077 0.105 0.037 0.030 0.030 0.065 

Sr ep 0.003 0.005 0.002 0.004 0.003 0.005 0.002 0.004 0.006 0.016 0.016 0.025 0.005 0.003 0.004 0.007 0.002 0.002 0.004 0.005 

Shet 0.004 0.002 0.001 0.003 0.004 0.002 0.001 0.003 0.017 0.025 0.031 0.016 0.001 0.004 0.004 0.003 0.002 0.003 0.004 0.003 

Sanl 0.012 0.022 0.005 0.007 0.012 0.022 0.005 0.007 0.001 0.006 0.001 0.000 

SNIST 0.014 0.023 0.006 0.008 0.014 0.023 0.006 0.008 0.018 0.030 0.035 0.030 0.005 0.005 0.006 0.007 0.003 0.007 0.005 0.006 

NAV 0.018 0.100 0.016 0.017 0.536 0.428 0.189 0.312 0.215 0.177 0.089 0.134 0.037 0.030 0.030 0.068 

NAU 0.015 0.028 0.006 0.008 0.111 0.092 0.047 0.070 0.083 0.062 0.024 0.050 0.010 0.008 0.008 0.017 

All Lab R epor t P age 3 / 6 

G4
Round Robin XLVI Laboratory Results 

All values in μg/mL 

Lab 

Total α-Cryptoxanthin 

255 256 257 258 

Total Lutein Total Zeaxanthin Total Lutein&Zeaxanthin Coenzyme Q10 

FSV-BA 0.009 0.013 0.014 0.028 

FSV-BB 0.016 0.016 0.016 0.016 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BGa 

FSV-BH
 

FSV-BI
 

FSV-BJ
 

FSV-BK
 

FSV-BL
 

FSV-BM
 

FSV-BN
 

FSV-BO
 

FSV-BP
 

FSV-BQ
 

FSV-BR
 

FSV-BS
 

FSV-BT
 0.023 0.023 0.017 0.024 

FSV-BU 

FSV-BV 

FSV-BW
 

FSV-BX
 

FSV-BZ
 

FSV-CB
 

FSV-CC
 

FSV-CD
 0.011 0.009 0.011 0.010 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CH 

FSV-CI
 

FSV-CK
 

FSV-CL
 0.045 0.043 0.024 0.034 

FSV-CN 

FSV-CR 

FSV-CS 

FSV-CT 

FSV-CV 

FSV-CX 

FSV-DB 

FSV-DD 

FSV-DF 

FSV-DH 

FSV-DK 

FSV-DP 

FSV-DR 

FSV-DU 

FSV-EH 

FSV-EM 

FSV-EQ 

FSV-ES 

FSV-FG 

255 256 257 258 

0.075 0.101 0.054 0.058 

0.072 0.071 0.044 0.060 

0.060 0.087 0.049 0.052 

0.062 0.091 0.047 0.067 

0.040 0.057 0.026 0.041 

0.062 0.084 0.043 0.052 

0.072 0.084 0.070 0.103 

0.041 0.069 0.043 0.044 

0.062 0.086 0.057 0.071 

0.063 0.098 0.048 0.058 

0.120 0.159 0.091 0.128 

0.041 0.097 0.060 0.062 

0.050 0.060 0.040 0.040 

0.052 0.063 0.042 0.020 

0.060 0.084 0.053 0.055 

0.052 0.069 0.039 0.043 

255 256 257 258 

0.042 0.036 0.027 0.041 

0.014 0.022 0.010 0.011 

0.032 0.026 0.028 0.038 

0.022 0.018 0.019 0.040 

0.049 0.031 0.018 0.037 

0.026 0.024 0.026 0.038 

0.026 0.028 0.019 0.045 

0.028 0.027 0.024 0.030 

0.028 0.027 0.025 0.034 

0.087 0.071 0.049 0.086 

0.020 0.020 0.020 0.030 

0.021 0.017 0.021 0.029 

0.027 0.019 0.024 0.035 

0.024 0.021 0.021 0.030 

255 256 257 258 

0.096 0.116 0.073 0.101 

0.117 0.137 0.081 0.099 

0.104 0.133 0.072 0.096 

0.094 0.107 0.061 0.077 

0.092 0.113 0.077 0.090 

0.084 0.109 0.066 0.107 

0.066 0.088 0.047 0.070 

0.091 0.093 0.047 0.080 

0.088 0.108 0.068 0.089 

0.054 0.077 0.059 0.091 

0.098 0.112 0.089 0.148 

0.056 0.080 0.075 0.106 

0.075 0.100 0.064 0.090 

0.069 0.096 0.067 0.075 

0.091 0.125 0.073 0.093 

0.081 0.112 0.068 0.095 

0.100 0.129 0.082 0.118 

0.097 0.135 0.092 0.133 

0.075 0.106 0.076 0.091 

0.092 0.110 0.078 0.117 

0.095 0.119 0.081 0.116 

0.207 0.230 0.140 0.214 

0.070 0.080 0.060 0.070 

0.088 0.106 0.070 0.096 

0.073 0.080 0.063 0.049 

0.087 0.103 0.077 0.090 

0.078 0.114 0.076 0.098 

0.129 0.135 0.062 0.117 

0.077 0.090 0.060 0.072 

255 256 257 258 

1.002 1.148 1.289 0.774 

0.180 0.403 0.438 0.213 

N 5 5 5 5 16 16 16 16 14 14 14 14 29 29 29 29 2 2 2 2 

Min 0.009 0.009 0.011 0.010 0.040 0.057 0.026 0.020 0.014 0.017 0.010 0.011 0.054 0.077 0.047 0.049 0.180 0.403 0.438 0.213 

Median 0.016 0.016 0.016 0.024 0.061 0.084 0.047 0.057 0.027 0.025 0.023 0.036 0.088 0.109 0.072 0.095 0.591 0.776 0.864 0.494 

Max 0.045 0.043 0.024 0.034 0.120 0.159 0.091 0.128 0.087 0.071 0.049 0.086 0.207 0.230 0.140 0.214 1.002 1.148 1.289 0.774 

eSD 0.009 0.007 0.002 0.009 0.010 0.017 0.009 0.014 0.006 0.006 0.005 0.007 0.016 0.017 0.010 0.013 

eCV 57 45 14 37 17 20 19 25 23 22 20 19 18 16 14 14 

Npas t 6 6 0 6 16 16 12 17 11 15 10 16 19 24 8 23 0 0 0 0 

Medianpas t 0.022 0.019 0.020 0.067 0.085 0.053 0.055 0.027 0.024 0.028 0.032 0.090 0.112 0.074 0.095 

SDpas t 0.008 0.006 0.004 0.034 0.015 0.013 0.019 0.008 0.009 0.014 0.009 0.020 0.035 0.008 0.020 

NISTa 0.068 0.091 0.055 0.059 0.017 0.018 0.014 0.020 0.086 0.109 0.070 0.079 

NISTb >0.056 >0.076 >0.045 >0.052 0.027 0.020 0.025 0.033 >0.083 >0.095 >0.071 >0.085 

NNIST 6 6 6 6 6 6 6 6 6 6 6 6 

MeanNIST 0.062 0.083 0.050 0.056 0.021 0.019 0.020 0.026 0.083 0.102 0.070 0.082 

Sr ep 0.003 0.003 0.003 0.004 0.002 0.003 0.002 0.005 0.005 0.005 0.004 0.009 

Shet 0.003 0.002 0.002 0.001 0.003 0.001 0.002 0.003 0.006 0.003 0.003 0.003 

Sanl 0.009 0.011 0.007 0.005 0.007 0.002 0.007 0.009 0.002 0.010 0.000 0.004 

SNIST 0.010 0.012 0.008 0.006 0.008 0.003 0.008 0.011 0.008 0.011 0.005 0.010 

NAV 0.061 0.084 0.049 0.056 0.024 0.022 0.021 0.031 0.086 0.106 0.071 0.088 

NAU 0.013 0.017 0.010 0.014 0.009 0.008 0.008 0.013 0.019 0.023 0.015 0.022 

All Lab R epor t P age 4 / 6 

G5
 

 

 

 

Round Robin XLVI Laboratory Results 

All Values in μg/mL 

Analytes Reported By One Laboratory 

Term 

N 

Min 

Median 

Max 

eSD 

eCV 

Npast 

Medianpast 

SDpast 

NNIST 

MeanNIST 

Srep 

Shet 

Sanl 

SNIST 

NAV 

NAU 

nd 

nq 

<x 

>x 

italics

Analyte Code 255 256 257 258 

9-cis-β-Carotene FSV-DH 0.013 0.008 0.006 0.004 

13-cis-β-Carotene FSV-DH 0.029 0.022 0.022 0.013 

9-cis-Lycopene FSV-DH 0.032 0.021 0.007 0.020 

13-cis-Lycopene FSV-DH 0.040 0.031 0.012 0.026 

15-cis-Lycopene FSV-DH 0.004 0.003 0.001 0.002 

Total cis-β-Cryptoxanthin FSV-BT 0.018 0.017 0.009 0.021 

Total Cryptoxanthin FSV-DH 0.043 0.033 0.039 0.088 

trans-Lutein NISTa 0.056 0.076 0.045 0.052 

Total anhydro-Lutein FSV-BT 0.038 0.038 0.024 0.032 

Phytoene FSV-CL nd 0.163 0.180 nd 

Phytofluene FSV-CL 0.085 0.068 0.123 0.052 

Legend 

Definition

 Number of (non-NIST) quantitative values reported for this analyte

 Minimum (non-NIST) quantitative value reported

 Median (non-NIST) quantitative value reported 

 Maximum (non-NIST) quantitative value reported

 Standard deviation for (non-NIST) results: 0.741*(3rd Quartile - 1st Quartile)

 Coefficient of Variation for (non-NIST) results: 100*eSD/Median

 Mean of N(s) from past RR(s)

 Mean of Median(s) from past RR(s)

 Pooled SD from past RR(s)
 

 Number of vials analyzed in duplicate by NIST analyst(s)

 Mean of the NIST-analyzed vial means

 W ithin-vial pooled standard deviation

 Among-vial pooled standard deviation

 Between NIST analyst standard deviation 

2

)

0.5 Total standard deviation for NIST analyses: (Srep 2

 + Shet 2 + Sanl 

 NIST Assigned Value

 = (Median + Mean)/2 for analytes reported by NIST analyst(s)
 

= Median for analytes reported by ≥ 10 labs but not NIST

2

)

0.5 NIST Assigned Uncertainty: (S2

 + Sbtw 

 S is the maximum of (0.05*NAV, SD, SNIST, eSD) and Sbtw is the standard

 deviation between Median and Mean. The expected long-term SD, eSD,

 is defined in: Duewer, et al. Anal Chem 1997;69(7):1406-1413.

 Not detected (i.e., no detectable peak for analyte)

 Detected but not quantitatively determined

 Concentration below the limit of quantification, x

 Concentration greater than x

 Not explictly reported but calculated by NIST from reported values

All Lab Report Page 5 / 6 

G6
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lab 

FSV-BA
 

FSV-BB
 

FSV-BD
 

FSV-BE
 

FSV-BF
 

FSV-BG
 

FSV-BGa
 

FSV-BH
 

FSV-BI
 

FSV-BJ
 

FSV-BK
 

FSV-BL
 

FSV-BM
 

FSV-BN
 

FSV-BO
 

FSV-BP
 

FSV-BQ
 

FSV-BS
 

FSV-BT
 

FSV-BU
 

FSV-BV
 

FSV-BW
 

FSV-BX
 

FSV-BZ
 

FSV-CB
 

FSV-CC
 

FSV-CD
 

FSV-CE
 

FSV-CF
 

FSV-CG
 

FSV-CH
 

FSV-CI
 

FSV-CK
 

FSV-CL
 

FSV-CN
 

FSV-CR
 

FSV-CS
 

FSV-CT
 

FSV-CV
 

FSV-CX
 

FSV-DB
 

FSV-DD
 

FSV-DF
 

FSV-DH
 

FSV-DK
 

FSV-DR
 

FSV-DU
 

FSV-EH
 

FSV-EM
 

FSV-EQ
 

FSV-ES
 

FSV-FG
 

NISTa 

NISTb 

n 

StS 

1 

2 

3 

4 

Round Robin XLVI Laboratory Results
 

Comparability Summary
 

TR aT gT bC tbC aC Ly bX Label Definition 

1 1 1 1 1 1 1 2 Lab laboratory number 

2 1 1 1 1 2 1 1 TR "Standard Score" for Total Retinol 

1 1 1 1 aT "Standard Score" for α-Tocopherol 

1 1 1 2 gT "Standard Score" for γ-Tocopherol 

1 1 1 1 1 bC "Standard Score" for Total β-Carotene 

1 1 1 2 1 1 2 tbC "Standard Score" for trans-β-Carotene 

1 1 2 1 aC "Standard Score" for Total α-Carotene 

2 1 2 1 1 1 1 Ly "Standard Score" for Total Lycopene 

1 1 1 1 1 1 1 bX "Standard Score" for β-Cryptoxanthin 

1 1 1 2 1 1 2 n number of laboratories providing data for this analyte 

1 4 2 3 

2 1 2 1 "Standard Score" 

1 1 2 Given that our knowledge of the shape, location, and width of the measurement 

1 1 1 1 1 distributions is approximate and that a limited number of labs are involved, we
 

1 1 1 2 1 1 2
 summarize comparability with the following four-level "Standard Score" (StS)...
 

2 1
 

2 2 2
 StS Definition
 

4 3 1 2
 1 All StV within ±t(1-0.683,n-1) { ±1 SD}
 

4 4 3 2 3 2 1 1
 2 All StV within ±t(1-0.954,n-1) { ±2 SD}
 

1 3 3 2 1
 3 All StV within ±t(1-0.997,n-1) { ±3 SD}
 

4 2 1 2 1 1 1
 4 At least one StV > ±t(1-0.997,n-1) { >3 SD}
 

2 1 1 1
 

1 1 1 1 2 1 2
 where:
 

3 4 2 2 4 3 2
 StV Standardized Value, the distance in standard deviation units your value 

1 2 2 3 is from the "true" concentration: StV = (your value - NAV) / NAU
 

2 1 2 3 1
 

1 1 1 1 2 2 4
 NAV NIST Assigned Value, our estimate of the "true" analyte concentration
 

1 1 1
 

1 2 1 1 1
 NAU NIST Assigned Uncertainty, our estimate of the total measurement
 

2 1 2 2 1
 standard deviation (serum heterogeniety, analytical repeatibility,
 

2 2 2 1
 and among-laboratory reproducibility)
 

4 4 3 2 1 1
 

3 2 3 3 1
 Two-tailed student's t for coverage of ±1, ±2, and ±3 NAU about
 

1 4 4 1 1 1
 

t(1-a,n-1) 

NAV, assuming a normal population of size n 

2 2 2 2 1 3 3 

2 2 2 1 2 

3 2 1 2 1 2 3 1 

1 3 1 1 2 2 

4 4 4 4 

1 1 2 1 1 

2 1 1 

1 1 1 1 

2 

3 4 4 1 

2 3 3 1 1 2 1 

2 2 1 

4 4 2 

2 4 3 2 2 

4 2 2 2 1 

2 3 2 

3 2 1 1 3
 

2 3
 

1 1 1 1 1 1
 

1 1 1 1 1 

48 49 29 34 15 30 28 28 

% Observed Expected 

42 49 48 50 53 60 61 54 68.2 % These are the observed and normal-population-expected proportions 

38 22 17 41 40 33 25 29 27.2 % of each Standard Score (StS), based upon each laboratory's largest
 

6 14 21 6 7 0 14 14
 4.3 % StV for the four sera. 

15 14 14 3 0 7 0 4 0.3 % 

All Lab Report Page 6 / 6 

G7
Appendix H. Representative “Individualized Report” for RR46 

Each participant in RR46 received an “Individualized Report” reflecting their reported 

results. Each report included a detailed analysis of the results they reported for the 

following analytes: 

• Total Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ-Tocopherol 

• Total β-Carotene 

• trans-β-Carotene 

• Total α-Carotene 

• Total Lycopene 

• trans-Lycopene 

• Total β-Cryptoxanthin 

• Total Lutein 

• Total Zeaxanthin 

• Total Lutein & Zeaxanthin 

The following 12 pages are the “Individualized Report” for the analytes evaluated by 

participant FSV-BA. 

H1
 

 Set 1 of 54

Individualized Round Robin XLVI Report: FSV-BA 

Summary 

Serum 255 Serum 256 Serum 257 Serum 

Analyte You NAV n You NAV n You NAV n You N

Total Retinol 1.089 0.990 48 0.467 0.480 48 0.504 0.549 46 0.787 0

Retinyl Palmitate 0.08 0.03 12 0.1 0.1 16 0.2 0.2 16 0.06 0

α-Tocopherol 28.12 27.99 49 17.89 17.07 49 5.23 5.01 48 7.50 7

γ-Tocopherol 5.815 6.015 29 1.532 1.549 29 1.955 2.009 29 3.538 3

Total β-Carotene 0.399 0.367 34 0.488 0.424 34 0.411 0.360 34 0.186 0

trans-β-Carotene 0.362 0.338 15 0.453 0.415 15 0.382 0.361 15 0.173 0

Total cis-β-Carotene 0.037 0.030 10 0.034 0.028 10 0.029 0.030 10 0.013 0

Total α-Carotene 0.008 0.018 29 0.095 0.100 30 0.011 0.016 29 0.010 0

trans-Lycopene 0.289 0.215 14 0.244 0.177 14 0.114 0.089 14 0.185 0

Total β-Cryptoxanthin 0.030 0.037 28 0.026 0.030 28 0.030 0.030 28 0.085 0

Total α-Cryptoxanthin 0.009 5 0.013 5 0.014 5 0.028 

Total Lutein&Zeaxanthin 0.096 0.086 29 0.116 0.106 29 0.073 0.071 29 0.101 0

H2

You : Your reported values for the listed analytes (micrograms/milliliter) 

NAV : NIST Assigned Values, equal to (NIST's average-of-averages + this RR's median) / 2 

n : Number of non-NIST laboratories reporting quantitative values for this analyte in this serum 

Please check our records against your records. Send corrections and/or updates to... 

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology Tel: (301) 

100 Bureau Drive Stop 8392 Fax: (301) 

Gaithersburg, MD 20899-8392 USA Email: david.duewer

 Individualized Report 
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

Total Retinol 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 2 / 12 

H3
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

Retinyl Palmitate 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 3 / 12 

H4
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

α-Tocopherol 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 4 / 12 

H5
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

γ-Tocopherol 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 5 / 12 

H6
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

Total β-Carotene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 6 / 12 

H7
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

trans-β-Carotene Your [Analyte], μg/mL

[Analyte], μg/mL 

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see:
 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999.
 

Serum History Comments
 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99)
 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93)
 

#258 #248 in RR44 (9/98) SRM 968c, Level I
 

#256 #249 in RR44 (9/98) SRM 968c, Level II
 

 Individualized Report Page 7 / 12 H8
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

Total cis-β-Carotene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 8 / 12 

H9
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

Total α-Carotene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 9 / 12 

H10
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

trans-Lycopene 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 10 / 12 

H11
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

Total β-Cryptoxanthin 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 11 / 12 

H12
 

 

 Set 1 of 54

Individualized RR XLVI Report: FSV-BA 

Total Lutein&Zeaxanthin 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193 254 255 171 176 257 248 258 249 256 Median [Analyte], μg/mL 

Serum 

Apparent Precision, SD 

Apparent Precision, SD 

Concordance, SD Long-term Precision, SD 

3rd Quartile (75%) SRM 968c 

You, this RR You, >x, this RR NIST, this RR ~95% confidence range 

Median (50%) on expected value You, >x, past RRs You, past RRs Others, this RR 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Serum History Comments 

#255 #193 in RR30 (3/94), #254 in RR45 (3/99) 

#257 #171 in RR26 (10/92), #176 in RR27 (3/93) 

#258 #248 in RR44 (9/98) SRM 968c, Level I 

#256 #249 in RR44 (9/98) SRM 968c, Level II 

 Individualized Report Page 12 / 12 

H13
Appendix I. Shipping Package Inserts for RR12 

The following four items were included in each package shipped to each RR12 

participant: 

• Cover letter 

• Protocol for analyzing samples 

• Preparation of Stock Solution and Diluted Solution Datasheet 

• Results Datasheet 

The cover letter, protocol, and datasheet were enclosed in a sealed waterproof bag along 

with the samples themselves. 

I1
I2
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Protocol for analyzing samples 

The control sample consists of a sample of solid ascorbic acid in an amber vial and should be used in 

the following manner (please record your weights on the attached report form): 

1.	 Prepare 250 mL of 5% metaphosphoric acid (MPA) in distilled water. 

2.	 Weigh out 180-220 mg of the solid ascorbic acid sample to 0.1 mg (if possible) and 

dissolve it in 100 mL of 5% MPA using a 100 mL volumetric flask. Weigh the amount of 

MPA solution that was added. This will be referred to as the Stock Solution. 

3.	 Dilute the Stock Solution by weighing 0.5 mL of the stock solution into a 100 mL 

volumetric flask. Then add 5% MPA solution to 100 mL and weigh the amount of MPA 

solution that was added. 

4.	 Record the ultraviolet spectrum of the diluted solution against 5% MPA solution as the blank 

using paired cuvettes. 

5.	 Record the absorbance of the sample at 243 and 244 nm. 

6. Measure the concentration of the ascorbic acid in the dilute solution in duplicate along with 

the ampuled Test Samples. 

The Test Samples are in sealed ampules and were prepared by adding equal volumes of 10% 

metaphosphoric acid to spiked human serum. We have checked the samples for stability and 

homogeneity and the total ascorbic acid appears to be sufficiently stable however, these samples 

contain some dehydroascorbic acid. The Test Samples should be defrosted by warming at 20 °C for not 

more than 10 min otherwise some oxidation of ascorbic acid may occur. 

Each ampule should contain between 10 and 120 μmol of ascorbic acid/ L of diluted serum and 

each ampule should be analyzed in duplicate by the method(s) used in your laboratory (preferably 

one measuring total ascorbic acid). 

I3
 

 

 

 

 

 

 

 

 

 

 

REPORT OF ANALYSIS
 

NAME: 

ADDRESS: 

Telephone no.: 

Fax no.: 

Method of Analysis: 

Please attach representative chromatograms.
 

Method used for calculating ascorbic acid concentration.
 

Peak height Peak area
 

Manufacturer of ascorbic acid used to make in-house standards
 

Date of Analysis:
 

PREPARATION OF STOCK SOLUTION AND DILUTED SOLUTIONS 

STOCK SOLUTION 

Weight of ascorbic acid in the Stock Solution 

Weight of 5% MPA added to the 100 mL volumetric flask

mg 

g 

DILUTE SOLUTION 

Weight of added stock solution (0.5 mL)

Weight of 5% MPA added to the 100 mL volumetric flask

 mg 

g 

Absorbance of Dilute Solution 1 at 243 nm 

Absorbance of Dilute Solution 1 at 244 nm 

COMMENTS: 

I4
 

 

 

 

CONTROL SAMPLE 1 

REPLICATE 1

REPLICATE 2

TEST SAMPLE LOW VIAL # 

REPORT OF ANALYSIS
 

RESULTS (μmol/L)
 

 μmol/L 

 μmol/L 

REPLICATE 1 μmol/L
 

REPLICATE 2 μmol/L
 

TEST SAMPLE HIGH VIAL # 

REPLICATE 1 μmol/L 

REPLICATE 2 μmol/L 

UNKNOWN VIAL # 

REPLICATE 1 μmol/L 

REPLICATE 2 μmol/L 

UNKNOWN VIAL # 

REPLICATE 1 μmol/L 

REPLICATE 2 μmol/L 

I5
 

 

 

Appendix J. “Final Report” for RR11 and RR12 

The following seven pages are the “Final Report” as provided to all participants in RR11 

and/or RR12, with the following exceptions: 

•	 the participant identifiers (Lab) have been altered. 

•	 the order in which the participant results are listed has been altered. 

•	 the Figure and Tables have been updated to report results in units of
 

“μmol/L sample” rather than the original “μmol/L serum”, where:
 

μmol/L sample = (μmol/L serum)/2.
 

•	 some of the results listed in the current Tables and Figure differ from those in the 

original “Final Report” because of later-resolved confusion in the reporting units. 

Note, however, that the results discussed in the Dr. Margolis’s text have not been 

updated or corrected. 

The data summary in the “Final Report” has been altered to ensure confidentiality of 

identification codes assigned to laboratories. The only attributed results are those 

reported by NIST. The NIST results are not used in the assessment of the consensus 

summary results of the study. 

J1
 

 

 

 

 

 

August 9, 1999 Dr. Margolis printed a separate cover letter for 

each participant. The words within the “«»” 

«Name» 

are parameters for a mail-merge macro 

routine. 

« Company» 

«Address» 

Dear «Name»: 

This report describes the overall-group and your laboratory performance in Round Robin 11 

(RR11) and Round Robin 12 (RR12) for the measurement of ascorbic acid (AA) in human 

plasma. These studies involved both the duplicate analyses of two samples of candidate SRM 

970 Ascorbic Acid in Human Serum and a solid ascorbic acid sample as a standard. Your results 

are designated as Lab. No(s). «Lab No.» in the tables and figures. 

Table 1 provides a summary of the data submitted by the participating laboratories (the NIST 

data were not included in the statistical analysis). Three laboratories submitted two sets of 

measurements, each done by a different method. As shown in Table 1, the among-laboratory 

coefficient of variation (CV) for levels 1 and 2 were 24% and 15% for RR11, and 23% and 12% 

for RR12. The median within-laboratory measurement-repeatability CV for levels 1 and 2 were 

less than 5% for both levels in both exercises. 

These results indicate that the within-laboratory variation remains essentially unchanged from 

the two previous round robins. However, the among-laboratory CV may have slightly increased 

from RR10. The box plots in your report graphically summarize the results, the box contains the 

values from 50% of the data sets distributed closest to the median. The NIST mean value for the 

"total" ascorbic acid (ascorbic acid + dehydroascorbic acid) is represented by a solid line and the 

NIST mean for ascorbic acid (alone) is represented by the dashed line. The horizontal line in the 

50% boxes represents the median interlaboratory values. The distribution of the laboratory 

results is illustrated in Figure 1. These plots suggest that many of the laboratories are not 

measuring all of the dehydroascorbic acid. 

We asked each of you to make up a solution from solid ascorbic acid, measure its UV 

absorbance, and assay the ascorbic acid content. We also asked you to weigh all of the solutions 

used to make this standard. The purpose of this segment of the study was to try to evaluate the 

role that your standards and your measurement technique might be playing in the accuracy and 

precision of your measurement process. The results of the measurements on ascorbic acid 

solutions are summarized in Tables 2 and 3. The ascorbic acid concentrations were calculated 

from the weights that you reported, and the volume of metaphosphoric acid (MPA) was 

calculated by using a density of 1.004 g/L (21 °C) for 5% MPA. The analysis of the weights of a 

500 mL aliquot of the AA stock solution gave a mean of 519.4 mg, SD 8.8, CV 1.7 (range 507 ­

540 mg) for RR11 and a mean of 515.4 mg, SD 9.2, CV 1.8 (range 500 - 527 mg) for RR12. The 

volumes were calculated from the weighed amounts of 100 mL of MPA into the 100 mL 

volumetric flask using the density of 5% MPA. The results of this calculation gave a mean of 

J2
 

 

 

 

 

102.3 g, SD 0.5, and CV 0.5 (range 101.6-103.7 g) for RR11 and 102.6 g, SD 0.2, and CV 0.2 

(range 100.3-102.9 g) for RR12. These data indicate that you are able to accurately weigh 

samples between 0.500 and 100 g. It also indicates that the pipettes that were used to measure 

sub-mL volume s are biased high by ≈4% at 500 mL. An important question that is not answered 

in this study is whether this is a constant bias or proportional to the volume being measured. 

However, it strongly suggests that each laboratory should calibrate its micropipettes over the 

range that they are used. One way to do this is to weigh a series of aliquots (5-10) of a liquid 

such as water, convert the weights to volumes using the density of water (at the appropriate 

temperature), and calculate the accuracy and precision of the pipette and pipetting technique (see 

ASTM method for a detailed method). 

Using the data that you submitted to us, we calculated the concentration of the AA in the 

standard solution (the “Calc.” columns, Table 1) which each of you made and assumed that the 

error in concentration was no greater than the error in weighing 0.5 to 100 g. The amount of AA 

that you actually measured in your assay of the standard solution is listed in the “Meas.” columns 

of Table 1. To compare the measurements on the standard solutions, we normalized all of the 

data obtained by assaying the standard solution to a starting concentration of 50 mmol/L using 

the equation: 

assayed [AA] = normalized [AA] 

weighed [AA] = 50 

The mean of these data is 51.3, SD 4.6, CV 9.0 (range 42.7 - 57.5 mmol/L) for RR11 and 50.9, 

SD 4.9, CV 9.6 (range 42.7 - 57.5 mmol/L) for RR12. If the estimated error in weighing and in 

filling the volumetric flasks is small (1 - 2%), then the major source of error is in the assay itself. 

This would include: 1) the accuracy of the pipets, 2) the accuracy of the standards (particularly if 

they are diluted), 3) the accuracy of the volume of the sample standard and/or serum delivered to 

the assay mixture, and 4) the accuracy of any constants used in the calculation of the 

concentration of the analyte from the results of the assay. 

Finally we asked each of you to measure the absorbance of your standard solution at 243 nm and 

244 nm. At these wavelengths we determined, on a spectrophotometer calibrated for wavelength 

and absorbance accuracy, that ascorbic acid in MPA exhibits its maximum absorbance. Every 

laboratory obtained similar values at each wavelength indicating that the wavelength was correct; 

however, the mean El% for a 1 cm cell was 581 AU/mole/cm, SD 34, CV 5.8 in RR11 and 563 

AU/mole/cm, SD 15, CV 2.7 in RR12. At NIST the El% was determined for Fisher and Sigma 

samples of AA and the values were 529 and 533 AU/mole/cm respectively. The reported values 

for the Fisher ascorbic acid varied from 525 to 668 AU/mole/cm for RR11 and 540 to 584 

AU/mole/cm for RR12. These results indicate that there is a need among some laboratories to 

calibrate their spectrophotometers with absorbance standards such as NIST SRM 2031. For 

those laboratories whose El% was at the high or low end of the distribution curve, we recommend 

checking the wavelength accuracy of the spectrophotometer. 

In conclusion we can identify the following sources of systematic bias in the measurement s: 

1. The spectroscopic error in the measurement of the absorbance of a standard solution at a 

specified wavelength (CV = 9-10). 

2. The pipetting of aqueous solutions (mean 3-4% above expected value). 

J3
 

 

 

 

 

3. The weighing of samples 0.5-100 g (CV of 1 and 2% respectively). 

4. The measurement of the concentration of a 50 mmol/L standard solution (mean = 5 1 

mmol/L , CV= 9-10%). The mean value is close to the expected value; therefore the 

error probably lies in the accuracy of the measurement of the sample or the calculation 

constants. 

5. The measurement of the serum AA. This could either reflect inaccurate dispensing of the 

total sample to the assay because of the viscosity of the sample, inaccurate constants used 

in calculating the AA concentration, or incomplete reduction of the dehydroascorbic acid. 

If your values differed from those of NIST by more than 5%, we suggest that you evaluate 

whether you accurately deliver the correct sample volume which can vary either as a function of 

the sample viscosity or the accuracy of the pipette. Alternatively, we suggest that you evaluate 

the accuracy of the constants that you use in converting the assay results to a final AA 

concentration in the serum or the completeness of the reduction of the dehydroascorbic acid or 

the oxidation of the ascorbic acid. If your results deviate significantly from the assigned values, 

we suggest that you reexamine your methods for possible systematic errors. 

The next set of samples (RR13) will be shipped during January 2000. If you have any questions 

concerning the previous round robins please contact me at 301/975-3137 or by e-mail at 

sam.margolis @nist.gov. 

Sincerely , 

Sam A. Margolis, Ph.D. 

Research Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

J4
Table 1: Round Robin 11 and 12 for the Measurement of AA in Human Serum 

Ascorbic Acid (μmol/L Sample) 

Lab.No. Methoda Calc. Meas. Level 1 Level 2 Calc. Meas. Level 1 Level 2 

VC-MA HPLC-EC 57.8 6.1 7.2 25.2 54.3 7.7 23.7 

VC-MB Enz-OPD 57.8 64.0 12.4 31.5 58.3 54.3 9.0 27.4 

VC-MC HPLC-EC 57.9 71.4 12.0 35.8 57.4 63.7 11.5 32.3 

VC-MD DNPH 48.8 7.0 34.3 48.6 8.7 34.0 

VC-ME HPLC-UV 56.9 54.6 7.3 27.1 

VC-MF Enz-OPD 55.3 8.1 27.1 

VC-MH HPLC-EC 56.8 58.0 8.6 26.2 

VC-MI HPLC-UV 59.3 62.2 8.7 29.8 

VC-ML HPLC-UV 56.3 57.0 9.9 28.5 55.0 52.3 7.0 25.4 

VC-MO HPLC-OPD 53.0 53.8 7.2 24.6 56.3 58.0 8.0 26.7 

VC-MQ DCIP 57.7 68.1 6.5 33.3 

VC-MT HPLC-EC 62.9 67.4 11.4 31.7 

VC-MV HPLC-EC 56.4 61.4 9.0 28.7 

VC-MW DNPH 55.4 59.5 8.0 21.1 

VC-MX HPLC-EC 56.3 56.6 11.4 25.2 

VC-MZ HPLC-EC 57.3 57.2 8.2 28.1 

VC-NA HPLC-EC 54.6 50.8 8.6 14.2 

VC-MG HPLC-UV 54.8 5.5 26.8 

VC-NC DNPH 55.9 63.6 13.6 36.3 

VC-ND HPLC-EC 58.4 48.6 12.1 28.1 

VC-NI Enz-OPD 55.2 48.7 8.6 30.0 

VC-NJ Enz-OPD 62.4 70.1 8.7 28.4 

VC-NO HPLC-UV 63.0 56.3 10.0 26.9 

VC-NQ HPLC-OPD 56.7 52.7 7.9 26.7 

VC-NV HPLC-? 56.0 46.6 12.4 25.6 

NISTb HPLC-EC 9.5 31.7 10.3 32.2 

15 17 17 17 11 14 14 14 

Median 56.9 56.6 8.7 28.1 56.8 54.5 8.6 27.1 

eSD 1.5 7.0 2.1 4.3 1.4 6.9 1.2 3.2 

eCV 2.6 12.3 24.1 15.3 2.5 12.7 14.3 11.9 

a 

N 

AA = Ascorbic acid; DNPH = 2,4-Dinitrophenylhydrazine; EC = Electrochemical detector; 

Enz = Enzymatic assay; DCIP = Dichloroindophenol; HPLC = Liquid chromatography; 

OPD = Orthophenlyenediamine; TAA = Total ascorbic acid; UV = Ultraviolet absorbance 

Round Robin 11 Round Robin 12 

Standard SRM 970 Standard SRM 970 

b Not included in the summary statistics 

J5
 Table 2: Vitamin C Round Robin 11 

SRM 970, μmol/L Sample 

J6

Control Solution Level 1 L

Spectroscopy AA, μmol/L Vial 1 Vial 2 Combined Vial 1 Vial 2 

Lab Method Calc Avg Sdup Avg Sdup Avg Sdup Avg Sdup Avg S

OD243 OD244 E1% Mean Sdup Srep Stot 

VC-MA HPLC-EC 0.053 0.053 52 57.8 6.1 0.3 7.4 0.6 7.1 0.2 7.2 0.4 0.2 0.4 24.6 1.1 25.7 

VC-MB Enz-OPD 0.566 0.569 556 57.8 64.0 0.0 12.5 0.0 12.3 0.4 12.4 0.3 0.2 0.3 31.3 0.4 31.8 

VC-MC HPLC-EC 0.568 0.567 556 57.9 71.4 0.1 11.6 0.5 12.5 0.0 12.0 0.4 0.6 0.7 35.9 0.2 35.7 

VC-MD DNPH 48.8 0.5 7.0 0.8 7.0 1.0 7.0 0.9 0.0 0.9 34.5 0.1 34.1 

VC-ME HPLC-UV 0.569 0.574 567 56.9 54.6 0.1 6.4 0.5 8.1 0.6 7.3 0.5 1.2 1.3 27.4 0.2 26.8 

VC-MF Enz-OPD 55.3 0.3 8.2 0.0 8.0 0.1 8.1 0.1 0.2 0.2 27.1 0.0 27.0 

VC-ML HPLC-UV 0.568 0.565 573 56.3 57.0 1.5 10.1 0.5 9.6 0.3 9.9 0.4 0.3 0.5 28.6 0.9 28.5 

VC-MO HPLC-OPD 0.034 0.032 36 53.0 53.8 0.5 7.2 0.1 7.2 0.1 7.2 0.1 0.0 0.1 24.8 1.2 24.5 

VC-MV HPLC-EC 0.569 0.572 573 56.4 61.4 0.8 9.5 0.6 8.5 0.4 9.0 0.5 0.7 0.9 28.0 0.6 29.4 

VC-MW DNPH 0.542 0.541 556 55.4 59.5 0.1 8.3 0.1 7.6 0.2 8.0 0.2 0.5 0.6 21.2 0.2 21.0 

VC-MX HPLC-EC 0.621 0.621 627 56.3 56.6 1.5 11.3 0.3 11.4 0.3 11.4 0.3 0.1 0.3 25.2 1.0 

VC-MZ HPLC-EC 0.573 0.570 568 57.3 57.2 3.3 8.1 0.1 8.2 0.2 8.2 0.1 0.1 0.2 28.3 0.5 28.0 

VC-NA HPLC-EC 0.560 0.536 582 54.6 50.8 0.8 9.4 0.0 7.8 0.2 8.6 0.2 1.1 1.1 14.1 0.0 14.4 

VC-NC DNPH 0.587 0.595 597 55.9 63.6 0.3 13.8 0.3 13.5 0.2 13.6 0.2 0.2 0.3 36.4 0.9 36.2 

VC-ND HPLC-EC 0.572 0.570 556 58.4 48.6 1.2 12.6 0.5 11.6 0.0 12.1 0.4 0.7 0.8 28.3 0.0 28.0 

VC-NJ Enz-OPD 0.613 0.613 558 62.4 70.1 0.4 8.8 0.4 8.5 0.0 8.7 0.3 0.2 0.3 28.7 0.4 28.1 

VC-NO HPLC-UV 0.735 0.735 662 63.0 56.3 1.1 10.0 0.0 10.0 0.0 0.0 24.3 6.7 29.5 

NIST HPLC-EC 529 9.0 0.2 10.1 0.4 9.5 0.3 0.8 0.9 31.0 0.1 32.5 

N 15 15 15 15 17 17 17 

Min 0.034 0.032 36 53.0 6.1 0.0 7.0 0.0 0.0 0.0 

Median 0.569 0.570 567 56.9 56.6 0.5 8.7 0.3 0.2 0.4 

Max 0.735 0.735 662 63.0 71.4 3.3 13.6 0.9 1.2 1.3 

eSD 0.013 0.037 17 1.5 7.0 2.1 

ECV 2.3 6.4 3.0 2.6 12.3 24.1 
 Table 3: Vitamin C Round Robin 12 

SRM 970, μmol/L Sample 

J7

Control Solution Level 1 Le

Spectroscopy AA, μmol/L Vial 1 Vial 2 Combined Vial 1 Vial 2 

Lab Method Calc Avg Sdup Avg Sdup Avg Sdup Avg Sdup Avg S

OD243 OD244 E1% Mean Sdup Srep Stot 

VC-MB Enz-OPD 0.564 0.567 553 58.3 54.3 0.4 9.0 0.0 9.0 0.0 9.0 0.0 0.0 0.0 27.5 0.0 27.3 

VC-MC HPLC-EC 0.576 0.574 569 57.4 63.7 0.4 11.4 0.0 11.5 0.1 11.5 0.1 0.1 0.1 31.8 0.3 32.8 

VC-MD DNPH 0.576 0.574 569 57.4 48.6 0.0 8.7 0.1 8.6 0.0 8.7 0.1 0.1 0.1 34.5 0.9 33.5 

VC-MA HPLC-EC 0.072 0.072 67 61.1 53.1 0.2 7.6 0.5 7.8 0.3 7.7 0.4 0.1 0.4 23.9 1.3 23.5 

VC-ML HPLC-UV 0.555 0.546 572 55.0 52.3 0.4 6.9 0.1 7.0 0.0 7.0 0.1 0.0 0.1 24.6 0.1 26.3 

VC-MH HPLC-EC 0.561 0.560 561 56.8 58.0 1.2 9.1 0.5 8.2 0.4 8.6 0.4 0.7 0.8 25.6 0.5 26.8 

VC-MQ DCIP 0.567 0.565 557 57.7 68.1 1.2 6.3 0.4 6.6 0.2 6.5 0.3 0.2 0.4 32.4 1.0 34.2 

VC-MG HPLC-UV 0.540 0.541 537 57.2 54.8 0.7 5.1 0.9 6.0 0.7 5.5 0.8 0.6 1.0 26.6 0.5 27.1 

VC-MO HPLC-OPD 0.574 0.577 582 56.3 58.0 2.3 8.7 0.1 7.3 0.1 8.0 0.1 1.0 1.0 27.3 0.8 26.2 

VC-NI Enz-OPD 0.536 0.532 552 55.2 48.7 0.4 8.5 0.0 8.8 1.1 8.6 0.8 0.2 0.8 29.2 1.4 30.7 

VC-NV HPLC-? 0.570 0.570 578 56.0 46.6 0.3 12.9 0.1 11.9 0.3 12.4 0.2 0.7 0.8 23.3 1.0 27.9 

VC-NQ HPLC-OPD 0.539 0.538 539 56.7 52.7 0.2 7.7 0.1 8.2 0.2 7.9 0.2 0.4 0.4 26.6 0.6 26.8 

VC-MI HPLC-UV 59.3 62.2 0.4 8.8 0.3 8.6 0.2 8.7 0.3 0.2 0.3 30.2 0.2 29.4 

VC-MT HPLC-EC 0.609 0.613 554 62.9 67.4 0.8 11.6 0.5 11.2 0.3 11.4 0.4 0.3 0.5 30.9 0.2 32.5 

NIST HPLC-EC 10.5 0.4 10.2 0.3 10.3 0.4 0.2 0.4 32.3 0.1 32.2 

N 13 13 13 14 14 14 14 

Min 0.072 0.072 67 55.0 46.6 0.0 5.5 0.0 0.0 0.0 

Median 0.564 0.565 557 57.3 54.5 0.4 8.6 0.3 0.2 0.4 

Max 0.609 0.613 582 62.9 68.1 2.3 12.4 0.8 1.0 1.0 

eSD 0.017 0.018 18 1.5 6.9 1.2 

ECV 3.0 3.1 3.2 2.6 12.7 14.3 
Figure 1: Distribution of Participant Results in Round Robins 11 and 12

J8

Level 2 

TAA, Level 2

30 

Round Robin 11 

Average Value, μm ol/L Sam ple 

AA, Level 2

20 

Level 1 

TAA, Level 1

AA, Level 1 

10 

Round Robin 12 

0 

Participants, Rank-Ordered by Level 1 

Summary of the Round Robin 11 and Round Robin 12 results on the Measurement of Ascorbic Acid in SRM

970. Each point represents the average of two measurements on each of two vials. The dashed lines repres

NIST-determined values for ascorbic acid (AA) by itself. The solid lines represent NIST-determined value

for total ascorbic acid (TAA, AA + dehydroascorbic acid). 
Appendix K. Representative “Individualized Report” for RR11 and RR12 

Each participant in either RR11 and/or RR12 received an “Individualized Report” 

reflecting their reported results. The following two pages are the “Individualized Report” 

for participant VC-MA. 

K1
Set 1 of 25 

Individualized RR(Vitamin C) 11 &12 Report: VC-MA
 

AA MPA Stock MPA 

mg g mg g 

[AA] 

mmol/L 

A243 A244 

OD OD Date Method Sample 

RR 11: 09/23/98 HPLC-EC (Height) Control 200 103.09 526 102.45 57.8 0.0525 0.0527 

RR 12: 04/02/99 HPLC-EC (Height) Control 215 103.1 517.1 102.52 61.1 0.0721 0.0721 

Combined 59.5 

Replicates, [AA] μmol/L Duplicates

Rep1 Rep2 Factor Mean SDdup Mean SDdup 

K2

RR 11: 09/23/98 HPLC-EC (Height) SRM Lv 1, A 15.5 13.9 0.5 7.4 0.6 7.2 0.4 

RR 11: 09/23/98 HPLC-EC (Height) SRM Lv 1, B 14.0 14.5 0.5 7.1 0.2 

RR 12: 04/02/99 HPLC-EC (Height) SRM Lv 1, A 14.5 15.8 0.5 7.6 0.5 7.7 0.4 

RR 12: 04/02/99 HPLC-EC (Height) SRM Lv 1, B 16.1 15.1 0.5 7.8 0.3 

Combined 7.5 0.4 

RR 11: 09/23/98 HPLC-EC (Height) SRM Lv 2, A 50.7 47.7 0.5 24.6 1.1 25.2 1.5 

RR 11: 09/23/98 HPLC-EC (Height) SRM Lv 2, B 54.0 54.0 0.5 25.7 1.8 

RR 12: 04/02/99 HPLC-EC (Height) SRM Lv 2, A 49.5 45.9 0.5 23.9 1.3 23.7 1.0 

RR 12: 04/02/99 HPLC-EC (Height) SRM Lv 2, B 47.9 47.9 0.5 23.5 0.6 

Combined 24.4 1.3 

RR 11: 09/23/98 HPLC-EC (Height) Control 6.3 5.9 1.0 6.1 0.3 29.6 0.2 

RR 12: 04/02/99 HPLC-EC (Height) Control 53.3 53.0 1.0 53.1 0.2 

Please check our records against your records. Send corrections and/or updates to... 

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 USA Email: d

Individualized Report 
 

 

Set 1 of 25 

Individualized RR(Vitamin C) 11 &12 Report: VC-MA 

Ascorbic Acid Your [Ascorbic Acid], μg/mL

NISTTotal 

NISTTotal 

NISTAA 

11 12 11 12 11 12 

[Ascorbic Acid], μg/mL 

NISTAA 

Ctrl Level 1 Level 2 Median [Ascorbic Acid], μg/mL 

Apparent Precision, SD 

Concordance, SD 

Apparent Precision, SD 

Long-term Precision, SD 

3rd Quartile (75%) You, RR 12 NIST, RR 12 

Median (50%) 

You, RR 11 Others, RR 12 1st Quartile (25%) 

For details of the construction and interpretation of these plots, see: 

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem May 1, 1999. 

Sample	 Comments 

Ctrl	 Nominal 100 mg/L (56 μmol/mL) standard "control" solution prepared by participant from solid 

ascorbic acid provided by NIST. This material was from the same lot of material used to augment 

the SRM plasma pools and to prepare the gravimetric calibration solutions. 

SRMLo SRM 970 Level 1: Values are the mean of replicate determinations for two vials of each material 

SRMHi SRM 970 Level 2: Values are the mean of replicate determinations for two vials of each material 

Individualized report	 Page 2 / 2 

K3