NISTIR 7880-23 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2001 

Comparability Studies 

Results for Round Robin XLIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 14 Ascorbic Acid in Human Serum 

David L. Duewer 

Sam A. Margolis (Retired) 

Katherine E. Sharpless 

Jeanice B. Thomas 

 

 

 

 

 

NISTIR 7880-23
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2001 

Comparability Studies 

Results for Round Robin XLIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 14 Ascorbic Acid in Human Serum 

David L. Duewer 

Sam A. Margolis (Retired) 

Katherine E. Sharpless 

Jeanice B. Thomas 

Chemical Sciences Division 

Materials Measurement Laboratory 

July, 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 2001 MMQAP measurement comparability improvement studies: 1) Round Robin XLIX 

Fat-Soluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 14 Total Ascorbic Acid 

in Human Serum. The materials for both studies were shipped to participants in January 2001. 

Participants in Round Robin XLIX were requested to provide their measurement results by March 

16, 2001. Participants in Round Robin 14 were requested to provide their measurement results by 

May 12, 2001. 

Keywords 

Human Serum
 

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

Total Ascorbic Acid
 

iii 
 

 

 

 

 

 

 

Table of Contents 

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

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

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

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

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

Round Robin 14: Vitamin C in Human Serum............................................................................... 2
 

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

Appendix A. Shipping Package Inserts for RR49........................................................................ A1
 

Appendix B. Final Report for RR49 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR49 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR49 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR14 ......................................................................... E1
 

Appendix F. Final Report for RR14............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR14..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR14............................................... H1
 

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 total 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 XLIX: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

XLIX comparability study (hereafter referred to as RR49) received four lyophilized and one liquidfrozen 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 2001. 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 RR49 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 14: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 14 comparability study 

(hereafter referred to as RR14) received four frozen serum test samples and a solid ascorbic acid 

control material 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 January 

2001. The communication materials included in the sample shipment are provided in Appendix E. 

The test serum materials were prepared by adding equal volumes of 10 % metaphosphoric acid 

(MPA) to human serum that had been spiked with ascorbic acid. While these samples contain some 

dehydroascorbic acid, its content is variable. Therefore, the participants report only total ascorbic 

acid (TAA, ascorbic acid plus dehydroascorbic acid). Participants are also encouraged to prepare 

calibration solutions from the supplied solid control to enable calibrating their serum measurements 

to the same reference standard. 

The final report delivered to every participant in RR14 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 summarizes all of the reported measurement results and provides 

several consensus statistics. This report is reproduced as Appendix G. 

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

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 H. 

2
 
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 RR49 

The following three items were included in each package shipped to an RR49 participant: 

• Cover letter 

• Datasheet 

• Packing List and Shipment Receipt Confirmation Form 

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

samples themselves. The packing list was placed at the top of the shipping box, between 

the cardboard covering and the foam insulation. 

A1
---------·-----------------

... 

0 

0 

NIST CENTENNIAL 1'1 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20898-

January 16, 2001 

Dear Colleague: 

Happy New Year! Enclosed is the first set of samples for the quality assurance round robin exercise 

(Round Robin XLIX) for 2001. You will find one vial of each of one liquid-frozen and 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 March 16, 2001. 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 during the week of April 9, 2001. 

Lyophilized 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: Yigorous 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 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). Liquid-frozen sample 271 should not be reconstituted. 

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; cx-tocopherol, 75.8 at 292 nm; y-tocopherol, 

91.4 at 298 nm; ex-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 XLIX 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 at 

jbthomas@nist.gov; or mail/fax queries Jf the above address. 

S~cerely, l ---/J ~c- /)---· I lm.v 

Je · '"ce Brown Thomas J R~ arch Chemist 

Ailalytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

NISI 

A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin XLIX 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 269 270 271 272 273 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 

ubiquinone-10 (Q10) 

phylloquinone (K1) 

25-hydroxyvitamin D 

cholesterol 

Other analytes? 

* we prefer μg/mL 

Was serum 271 frozen when received? Yes | No 

Mail: M2QAP 

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

Gaithersburg, MD 20899-8392 16-Mar-2001 Email: David.Duewer@NIST.gov 

A3
 

 

 

 

Participant #: ________ Date: _____________ 

Round Robin XLIX
 

NIST Micronutrients Measurement Quality Assurance Program
 

Packing List and Shipment Receipt Confirmation Form
 

The enclosed bubble-pack (should) contain one vial each of the following five sera: 

Serum Form Reconstitute? 

#269 Lyophilized Yes (1 ml H2O) 

#270 Lyophilized Yes (1 ml H2O) 

#271 Liquid frozen No 

#272 Lyophilized Yes (1 ml H2O) 

#273 Lyophilized Yes (1 ml H2O) 

Please 1) Open the pack immediately 

2) Check that it contains one vial each of the above samples 

3) Check if serum #271 arrived frozen 

4) Store the RR XLIX samples upright at -20  ̊C or below until analysis 

5) Complete the following information 

6) Fax the completed form to us at 301-977-0685 

(or email requested information to david.duewer@nist.gov) 

1) Date this shipment arrived: ___________________________ 

2) Are all five vials intact? Yes | No 

If "No", which one(s) were damaged? 

3) Was there any dry-ice left in cooler? Yes | No 

4) Did serum #271 arrive frozen? Yes | No 

5) At what temperature are you storing the samples? _______  ̊C 

6) When do you anticipate analyzing these samples? ________________________ 

Thank you in advance for your prompt response. 

The M2QAP Gang 

Mail: M2QAP 

NIST, Stop 8392 Fax: 301-977-0685 

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

A4
Appendix B. Final Report for RR49 and Folate Questionnaire 

The following four 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 their previous distributions, 

if any, and 

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

participants. 

The fifth page of this section is a questionnaire that was distributed in the same mailing 

as the final report. This questionnaire was intended to assess the level of interest in the 

measurement of folates in serum and plasma. 

B1
r-~~--~~;11119'111111111ii!lil ~ 

• D 

0 

.,,, 

0 .._ __________ ..._. o 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20888-

NIST CENTENNIALO 

April 25, 2001 

Dear Colleague: 

Enclosed is the summary report of the results for Round Robin XLIX (RR 49) for fat-soluble vitamins 

and carotenoids. Included in this report are: a summary of data for all laboratories; the measurement 

comparability summary for evaluating laboratory performance; lyophilized vs. fresh-frozen 

commutability data, a summary of individual laboratory performance and interlaboratory accuracy and 

precision; and a summary of the NIST assigned value (NA V) vs. your laboratory value for the analytes 

that you measured. As in previous reports, the NIST-assigned values are 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 49 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 1to3 standard deviation(s) of the assigned value, respectively; those rated 4 are 

>3 standard deviations from the assigned value. 

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

unit of SRM 968c, Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum. If your 

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

The following are newly released or forthcoming publications. Reprints will be provided upon request. 

"Preparation and Value Assignment of Standard Reference Material 968c, Fat-Soluble Vitamins, 

Carotenoids, and Cholesterol in Human Serum," Brown Thomas et al., Clinica Chimica Acta 

305 (2001) 141-155. 

"The Stability of Ascorbic Acid in Autosampler Vials," Margolis, S.A. and Park, E., accepted by 

Clinical Chemistry, March 2001. 

The NIST Micronutrients Measurement Quality Assurance Workshop was held on April 4, 2001 as a 

symposium at the Experimental Biology (EB) meeting in Orlando, Florida. At the workshop, results 

from the past three interlaboratory comparison exercises (Round Robins 47-49), methodology updates, 

and program needs were discussed. There were 41 attendees at the workshop. As discussed at the 

session, the "better-than-expected" attendance was thought to be due to the workshop being held at the 

end of the conference instead of at the beginning. Since the EB meetings now begin a day earlier (on 

Saturday) than in the past, having the QA workshop at the end of the conference allows conferees to 

attend the EB meetings first and focus on the QA workshop afterwards. It was agreed that the next 

workshop will be held in conjunction with EB, which provides the appropriate audience, and will be held 

at the end of the conference. It was also suggested that our next QA workshop be held at EB 2003 in San 

Diego, CA. You will be notified about the next QA workshop as plans are made. 

Most of the discussion for the afternoon session at the workshop concerned the measurement of folates in 

serum. Attendees expressed that quality assurance of folate measurements in serum and a folate-inserum/plasma reference material are needed, and that they would like to start participating in round robin 

studies for folates in serum/plasma. To help us assess the level of interest in the measurement of folates 

in serum/plasma among the current QA program participants, please return the enclosed questionnaire 

by May 31. NISI 

B2
Another topic discussed at the workshop was the need to have more than one vitamin C round robin 

study so that laboratories can meet the requirements of the Clinical Laboratory Improvement 

Amendments (CLIA). Since there were not enough representatives from laboratories that routinely 

measure vitamin C present at the workshop, a decision about increasing the number of studies could not 

be made at that time. Again, we would appreciate your feedback regarding this issue by completing the 

enclosed questionnaire. Additionally, please be reminded that SRM 970, Vitamin C in Frozen Human 

Serum, is now available. This material can be purchased through the Standard Reference Materials 

Program at 301-975-6776; fax: 301-948-3730; or at srminfo@nist.gov. 

If you have any questions regarding this report, please contact David Duewer at 301/975-3935; e-mail: 

david.duewer@nist.gov, or me at 301/975-3120; e-mail: jbthomas@nist.gov; fax: 301/977-0685. 

D-i~ ~ · ce Brown Thomas 

earch Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

cc: 

L. C. Sander 

S.A.Wise 

Enclosures 

B3
 

 

1 

The NIST M2QAP Round Robin XLIX (RR49) report consists of 

Page 

2 to 

n 

n+1 

n+2 

“Individualized” Report 

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

“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 “target” plot version of your “Comparability Summary” scores.
 

An experimental “Commutability” plot summarizing your measurements in the five liquidfrozen / lyophilized sample pairs distributed in RR47, RR48, and RR49.
 

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 four analytes reported by only one laboratory. 

A legend for the above two lists
 

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

Samples. Five sera were distributed in RR49. 

Serum #269 is a lyophilized material that has been distributed in three previous studies, as #193 in 

RR30 (3/94), #254 in RR45 (3/99), and #255 in RR46 (6/99). It was prepared from a native serum 

pool augmented with “retinol” that we now believe was highly enriched in cis-isomers. Up to 30%
 

of the total retinol in this sample may be in the form of cis-retinols.
 

Serum #270 is a lyophilized material prepared from a native serum pool. The liquid-frozen partner of
 

this sample was distributed as #267 in RR48. Sera #267 and #270 were prepared and aliquoted into 

vials as a single batch.
 

Serum #271 is a liquid-frozen material prepared from a native serum pool. The lyophilized partner of
 

this sample was distributed as #266 in RR48. Sera #266 and #271 were prepared and aliquoted into 

vials as a single batch.
 

Serum #272 is a lyophilized material that has been distributed in two previous studies, as #223 and 

#225 in RR38 (9/96) and #228 in RR39 (3/97). It was prepared from a native serum pool augmented 

with retinyl palmitate.
 

Serum #273 is a lyophilized material that was distributed as #203 in RR33 (3/95). It was prepared 

from a native carotenoid-deficient serum augmented with retinol, retinyl palmitate, (α, γ, δ)­

tocopherols, (α, β)-carotenes, and lycopene.
 

Qualitative Observations. 

1)	 Several participants noted the presence an “insoluble stringy clot” in Serum #271. As noted in the 

RR48 report for #266, we failed to re-filter the final blend of the serum pool used for this sample. As 

with its lyophilized partner, the resulting solids do not appear to have affected measurements. 

2)	 One participant noted that what we’ve been reporting as γ-tocopherol is “really” γ- and/or βtocopherol. We now denote this measurand as “γ/β-tocopherol. 

3)	 All participants received their samples still frozen. We thank all of you who promptly confirmed 

receipt of the samples. Such prompt confirmation greatly simplifies our package delivery tracking 

and thus helps contain M2

QAP costs. We will be requesting similar confirmation in all future 

studies. 

B4
 

Quantitative Results 

1)	 With the possible exception of zeaxanthin, there have been no changes in the median level of any 

measurand in sera #269 (7 years storage), #272 (5 years), or #273 (6 years). There is, however, 

evidence of increased variability in retinol and α-tocopherol measurements, particularly in sera #272 

and #273. We believe that this increased variability may be related to contamination of many of the 

lyophilized sera prepared in the past 6 years. We will discuss this more fully in the RR50 report. 

As discussed in the RR45 report for serum #254, perhaps 30% of the retinol in Serum #269 is in the 

form of cis-isomers. While we did not intentionally spike this serum with cis-retinol, our methods 

indicate an unusually large retinol shoulder peak that is compatible with the presence of one or more 

of the cis-forms. 

2)	 The distribution of reported “retinol-related measurand” interlaboratory values is bimodal, with 

approximately equal numbers centered at about 0.9 μg/mL and 1.1 μg/mL. Somewhat distressingly, 

many of your are not correctly specifying the form you are actually measuring. Many of the reported 

“Total Retinol” values are more compatible with being “trans-Retinol”; many of reported “transRetinol” values are more compatible with being “Total”. 

If you report “Total Retinol” and your #269 value isn’t closer to 0.9 μg/mL than to 1.1 μg/mL, we 

suggest that you check your integration protocol to ensure that you are including cis-retinol isomers. 

If you report “trans-Retinol” and your #269 value isn’t closer to 1.1 μg/mL than to 0.9 μg/mL, we 

suggest that you confirm that your separation system does adequately resolve cis- and trans-retinol 

isomers. We intend to address this issue in the near future with explicitly cis-augmented samples. 

3)	 A total of five matched {liquid-frozen, lyophilized} matrix pairs have now been distributed: 

{261,259} and {262,260} in RR47, {265,268} in RR48, and {266,271} and {270,267} in RR48 and 

RR49. Since these pairs were prepared at the same time from the same serum pools, the ratio of the 

values in the two matrices (liquid-frozen / lyophilized) is a direct assessment of measurement 

commutability between the two matrices. The last page of your “Individualized Report” summarizes 

the community’s and your individual commutability ratios. 

We have not yet completed the detailed analysis of these data; however, a number of interesting 

results are already apparent: 

The average (liquid-frozen / lyophilized) ratio is 0.94, essentially identical to the 0.95 expected 

from serum density consideration. There is no systematic variation in this ratio across 

measurands. While there is considerable variability about this average with most of the “minor” 

carotenoids, much of this variability in the ratios is a consequence of limited reporting precision 

at low measurand levels (e.g., 0.0034/0.0036 = 0.94 but 0.003/0.004 = 0.75). 

There are several participants with retinol and/or tocopherol commutability ratios that are 

consistently above or below 0.94, indicating a systematic difference between the matrices in their 

measurement systems. We believe that this arises from contamination of the lyophilized samples 

used rather than a lyophilization-specific matrix effect. 

Note: since the {266,271} and {270,267} ratios involve measurements made half a year apart, the 

average of these two ratios (in logarithmic form) estimates commutability while the difference 

between the ratios estimates within-laboratory calibration differences between RR48 and RR49. 

B5
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lab number:
 

Phone:
 

Fax:
 

E-mail:
 

Questionnaire 

NIST Micronutrients Measurement Quality Assurance Program 

Please provide us with your input by completing this form and returning it by May 31, 2001 to: 

NIST Micronutrients Measurement Quality Assurance Program 

NIST 

100 Bureau Drive, Stop 8392 

 Gaithersburg, MD 20899-8392 

Fax: 301-977-0685 

Folates in serum/plasma are currently measured in my organization by: 

Name of the contact Phone Fax 

E-mail address 

I would participate and be willing to pay for a second annual QA 

interlaboratory comparison study for vitamin C if it were available. 

I am required to comply with the Clinical Laboratory Improvement 

Amendments and/or another laboratory standards program for the 

measurement of: 

 vitamin A  vitamin D 

 carotenes  vitamin K1 

 vitamin C  coenzyme Q10 

 vitamin E  other (please specify) 

Comments: 

B6
 

 

Appendix C. “All-Lab Report” for RR49 

The following eight 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 XLIX Laboratory Results 

All Values in μg/mL 

Total Retinol trans-Retinol Retinyl Palmitate α-Tocopherol 

Lab 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 

FSV-BA 1.25 0.688 0.495 0.564 1.35 0.070 nd 0.072 0.115 0.066 28.9 6.15 7.21 8.11 17.6 

FSV-BB 1.27 0.714 0.519 0.542 1.32 0.017 0.008 0.054 0.068 0.050 29.8 6.52 8.01 8.82 18.6 

FSV-BD 1.02 0.619 0.451 0.487 1.15 26.6 6.50 6.50 7.40 16.0 

FSV-BE 1.04 0.660 0.450 0.570 1.37 25.1 5.50 6.40 7.40 16.0 

FSV-BF 1.01 0.640 0.430 0.500 1.26 29.1 6.20 7.10 7.90 17.5 

FSV-BG 1.24 0.653 0.483 0.533 1.35 0.046 0.047 0.065 0.049 0.055 30.1 6.07 7.67 8.28 17.5 

FSV-BH 0.97 0.612 0.431 0.425 1.12 27.2 6.00 6.85 7.50 16.0 

FSV-BI 1.22 0.680 0.503 0.582 1.37 0.024 0.023 0.066 0.068 0.063 27.7 6.18 7.53 8.56 17.1 

FSV-BJ 1.11 0.634 0.460 0.509 1.21 nq nq 0.049 0.091 0.074 26.4 5.94 7.14 7.85 17.6 

FSV-BK 1.03 0.649 0.421 0.516 1.28 25.5 5.25 5.70 6.87 16.0 

FSV-BL 0.40 0.600 0.460 0.400 0.69 21.5 10.34 9.04 8.61 10.8 

FSV-BM 0.98 0.668 0.511 0.516 1.11 32.8 6.00 7.40 8.40 19.7 

FSV-BN 1.08 0.630 0.470 0.494 1.31 0.018 0.016 0.048 0.050 0.043 25.6 5.89 7.30 7.68 17.0 

FSV-BO 1.01 0.610 0.513 0.504 1.35 24.9 5.30 7.30 7.20 16.8 

FSV-BP 1.00 0.590 0.436 0.460 1.12 27.2 6.52 7.07 7.28 16.2 

FSV-BQ 1.17 0.674 0.496 0.550 1.33 24.4 5.07 6.22 7.44 15.8 

FSV-BR >1.04 >0.600 >0.440 >0.500 >1.15 1.04 0.600 0.440 0.500 1.15 24.5 4.90 5.86 6.96 14.9 

FSV-BS >1.05 >0.590 >0.440 >0.500 >1.18 1.05 0.590 0.440 0.500 1.18 

FSV-BT 1.12 0.599 0.643 0.506 1.24 0.026 0.014 0.046 0.081 0.070 26.8 5.83 5.56 7.59 16.6 

FSV-BU 0.88 0.603 0.458 0.413 1.18 27.6 5.43 6.83 7.35 16.8 

FSV-BV 0.94 0.570 0.440 0.450 1.10 26.7 5.94 7.71 7.71 16.8 

FSV-BW 1.19 0.660 0.490 0.540 1.36 0.022 0.018 0.062 0.071 0.076 28.4 6.04 7.32 8.10 17.5 

FSV-BX >1.02 >0.62 >0.46 >0.50 >1.14 1.02 0.620 0.455 0.501 1.14 25.0 5.65 6.90 7.54 15.9 

FSV-CB 0.95 0.591 0.419 0.473 1.18 25.7 5.96 7.03 7.67 16.2 

FSV-CC 1.11 0.670 0.460 0.510 1.26 1.03 0.630 0.450 0.490 1.21 27.9 6.10 7.00 7.50 16.2 

FSV-CD >1.18 >0.628 >0.450 >0.505 >1.19 1.18 0.628 0.450 0.505 1.19 0.013 0.033 0.022 0.179 0.041 27.6 5.94 6.99 8.36 17.0 

FSV-CE 1.16 0.670 0.510 0.570 1.30 29.5 6.70 8.07 9.08 17.2 

FSV-CF 1.08 0.663 0.474 0.512 1.31 25.5 6.50 7.90 8.20 16.5 

FSV-CG 1.13 0.715 0.510 0.560 1.28 24.7 5.59 6.75 7.19 13.8 

FSV-CH 0.94 0.542 0.376 0.431 1.01 26.3 5.92 7.01 7.92 15.3 

FSV-CI 0.88 0.710 0.520 0.550 1.42 0.030 0.030 0.060 0.060 0.050 31.2 5.60 6.70 7.60 16.9 

FSV-CL 0.99 0.534 0.389 0.396 1.08 31.6 7.54 9.01 9.89 19.3 

FSV-CR 1.14 0.720 0.490 0.550 1.35 28.3 6.00 6.90 7.90 18.2 

FSV-CV 0.49 0.488 0.283 0.205 0.58 0.110 0.083 0.103 0.144 0.120 30.3 7.69 7.82 9.04 16.9 

FSV-CW >0.99 >0.575 >0.401 >0.441 >1.15 0.99 0.575 0.401 0.441 1.15 0.012 0.016 0.046 0.065 0.065 27.4 5.82 6.86 7.60 16.7 

FSV-CZ 1.12 0.690 0.510 0.550 1.47 15.9 1.60 2.38 2.67 10.7 

FSV-DB 1.14 0.650 0.470 0.540 1.34 28.1 6.43 7.57 8.60 18.0 

FSV-DD >1.04 >0.600 >0.417 >0.525 >1.09 1.04 0.600 0.417 0.525 1.09 

FSV-DF 1.06 0.605 0.433 0.492 1.16 

FSV-DI >0.98 >0.606 >0.428 >0.466 >1.14 0.98 0.606 0.428 0.466 1.14 0.031 0.036 0.028 0.046 0.040 28.4 6.21 7.28 8.11 17.4 

FSV-DQ 36.8 7.04 10.24 13.42 26.2 

FSV-DR 1.19 0.650 0.490 0.510 1.33 31.9 6.58 7.99 8.23 19.2 

FSV-DU >1.16 >0.576 >0.406 >0.491 >1.20 1.16 0.576 0.406 0.491 1.21 24.4 4.32 5.51 6.19 14.3 

FSV-EH >1.07 >0.549 >0.468 >0.508 >1.26 1.07 0.549 0.468 0.508 1.26 0.031 0.032 0.070 0.070 0.062 28.1 5.75 6.59 7.00 16.6 

FSV-EQ 1.24 0.678 0.523 0.572 1.34 31.3 6.90 8.00 8.80 11.6 

FSV-FB >1.33 >0.760 >0.660 >0.773 >1.76 1.33 0.760 0.660 0.773 1.76 28.0 5.96 7.15 8.37 18.0 

FSV-FJ 1.01 0.640 0.470 0.470 1.05 27.7 6.08 7.43 8.06 15.4 

N 36 36 36 36 36 11 11 11 11 11 13 12 14 14 14 44 44 44 44 44 

Min 0.40 0.488 0.283 0.205 0.58 0.98 0.549 0.401 0.441 1.09 0.012 0.008 0.022 0.046 0.040 15.9 1.60 2.38 2.67 10.7 

Median 1.07 0.650 0.470 0.510 1.28 1.04 0.600 0.440 0.500 1.18 0.026 0.027 0.057 0.069 0.063 27.6 6.00 7.12 7.87 16.8 

Max 1.27 0.720 0.643 0.582 1.47 1.33 0.760 0.660 0.773 1.76 0.110 0.083 0.103 0.179 0.120 36.8 10.34 10.24 13.42 26.2 

eSD 0.13 0.050 0.050 0.059 0.11 0.04 0.036 0.022 0.013 0.05 0.012 0.015 0.015 0.023 0.018 2.8 0.56 0.62 0.70 1.2 

eCV 12 8 11 12 9 4 6 5 3 4 46 56 26 34 28 10 9 9 9 7 

Npast 47 44 44 49 49 7 11 11 0 0 11 11 15 15 9 47 52 52 47 47 

Medianpast 1.04 0.671 0.446 0.498 1.27 1.00 0.668 0.440 0.041 0.028 0.053 0.091 0.129 26.9 6.36 6.81 7.72 17.1 

SDpast 0.10 0.073 0.044 0.039 0.11 0.15 0.028 0.010 0.040 0.010 0.016 0.044 0.061 2.2 0.70 0.67 0.59 1.5 

23.9 5.28 6.76 7.14 16.3 

28.5 5.55 5.94 7.21 15.5 

3 4 4 4 4 

Mean 0.92 0.610 0.428 0.473 1.13 0.71 0.599 0.454 0.478 1.13 26.2 5.41 6.35 7.18 15.9 

Srep 0.02 0.017 0.016 0.008 0.02 0.02 0.024 0.019 0.010 0.00 0.3 0.14 0.29 0.12 0.2 

Shet 0.00 0.038 0.004 0.037 0.05 0.02 0.009 0.003 0.009 0.01 0.4 0.32 0.10 0.40 0.1 

Sanl 0.01 0.016 0.036 0.007 0.00 3.3 0.19 0.58 0.05 0.5 

SNIST 0.02 0.045 0.040 0.038 0.06 0.03 0.025 0.019 0.014 0.01 3.3 0.39 0.65 0.42 0.6 

NISTa 0.91 0.599 0.454 0.478 1.13 0.71 0.599 0.454 0.478 1.13 

NISTb 0.92 0.621 0.403 0.468 1.11 

NNIST 3 4 4 4 4 2 2 2 2 2 

NAV 

NAU 

0.99 

0.17 

0.630 

0.059 

0.449 

0.058 

0.491 

0.065 

1.20 

0.16 

0.88 0.599 0.447 0.489 1.16 

0.25 0.048 0.037 0.043 0.10 

0.026 0.027 0.057 0.069 0.063 

0.012 0.015 0.017 0.023 0.019 

26.9 5.71 

3.5 0.69 

6.74 

0.85 

7.52 16.3 

0.86 1.5 

All Lab Report C2 Page 1 / 8 
 

 

Round Robin XLIX Laboratory Results 

All Values in μg/mL 

γ/β-Tocopherol δ-Tocopherol Total β-Carotene		 trans-β-Carotene 

Lab 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273
 

FSV-BA
 6.42 2.29 1.96 1.76 1.22 0.347 0.480 0.331 0.165 0.051 0.316 0.460 0.323 0.155 0.051 

FSV-BB 6.18 2.30 2.03 1.78 1.21 0.366 0.490 0.355 0.158 0.063 0.338 0.470 0.338 0.155 0.045 

FSV-BD 0.376 0.548 0.367 0.192 0.074
 

FSV-BE
 5.90 2.10 1.80 1.70 1.10 0.357 0.486 0.295 0.156 0.050
 

FSV-BF
 5.60 2.50 1.90 1.70 1.10 0.440 0.586 0.410 0.169 0.031 

FSV-BG 6.72 2.23 2.06 1.88 1.20 0.366 0.543 0.350 0.174 0.058 

FSV-BH 6.56 2.43 2.06 1.84 1.24 0.375 0.505 0.357 0.168 0.048 0.342 0.481 0.336 0.159 0.048 

FSV-BI 6.47 2.43 2.17 2.01 1.23 0.360 0.518 0.373 0.172 0.056
 

FSV-BJ
 6.23 2.33 2.05 1.81 1.31 0.397 0.565 0.451 0.172 0.060 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 4.72 1.79 1.62 1.37 0.96 0.700 0.250 0.310 0.340 3.39 0.336 0.471 0.352 0.148 0.053 0.300 0.442 0.324 0.140 0.052 

FSV-BO 0.367 0.506 0.410 0.180 0.064
 

FSV-BP
 0.380 0.453 0.310 0.183 nd 

FSV-BQ 

FSV-BR 

FSV-BS >0.222 >0.292 >0.180 >0.082 >0.034 0.222 0.292 0.180 0.082 0.034 

FSV-BT 5.86 2.32 1.56 1.68 1.20 0.757 0.748 0.233 0.336 3.38 0.314 0.436 0.317 0.143 0.057 0.288 0.416 0.298 0.135 0.053 

FSV-BU 6.16 2.30 2.05 1.73 1.12 0.375 0.535 0.362 0.175 0.058
 

FSV-BV
 6.44 2.48 2.21 1.89 1.28 0.351 0.506 0.365 0.169 0.057 

FSV-BW 6.75 2.46 2.17 1.96 1.24 0.350 0.500 0.350 0.160 0.054
 

FSV-BX
 6.02 2.22 1.96 1.75 1.13 >0.317 >0.467 >0.336 >0.165 >0.076 0.317 0.467 0.336 0.165 0.076 

FSV-CB 0.367 0.497 0.345 0.170 0.056 

FSV-CC 

FSV-CD 5.77 2.24 1.94 1.90 1.24 0.390 0.515 0.332 0.140 0.060 

FSV-CE 0.390 0.570 0.430 0.200 0.050 

FSV-CF 

FSV-CG 6.32 2.29 2.11 1.82 1.21 0.492 0.123 0.171 0.228 2.48 0.368 0.472 0.352 0.164 0.059 0.334 0.446 0.328 0.154 0.052 

FSV-CH 5.65 2.17 1.87 1.61 1.06 0.233 0.440 0.322 0.153 0.051
 

FSV-CI
 6.00 1.80 1.70 1.60 1.10
 

FSV-CL
 6.84 2.73 2.39 1.95 0.98 0.321 0.432 0.292 0.153 0.049 

FSV-CR 

FSV-CV 16.17 5.81 4.36 4.15 2.53 0.432 0.111 0.118 0.166 2.64 0.467 0.691 0.394 0.173 0.038 

FSV-CW 6.31 2.32 2.01 1.80 1.23 0.390 0.090 0.110 0.160 3.14 0.344 0.469 0.332 0.157 0.055 0.310 0.442 0.308 0.147 0.051 

FSV-CZ 0.380 0.530 0.410 0.210 0.110 

FSV-DB 0.400 0.530 0.360 0.170 0.070 

FSV-DD 

FSV-DF 

FSV-DI 5.60 2.03 1.73 1.53 1.01 0.378 0.084 0.106 0.153 3.22 >0.320 >0.439 >0.293 >0.135 >0.039 0.320 0.439 0.293 0.135 0.039 

FSV-DQ 9.39 2.76 2.73 2.83 1.92 0.485 0.431 0.483 0.337 0.106 

FSV-DR 0.350 0.528 0.390 0.119 0.070 

FSV-DU >0.274 >0.376 >0.252 >0.118 >0.021 0.274 0.376 0.252 0.118 0.021 

FSV-EH 6.06 2.01 1.92 1.65 1.24 0.313 0.106 0.118 0.196 2.15 0.339 0.463 0.337 0.158 0.070 0.281 0.419 0.296 0.135 0.048 

FSV-EQ 0.335 0.471 0.328 0.165 0.052 0.323 0.463 0.328 0.162 0.052 

FSV-FB 0.326 0.390 0.313 0.178 0.073 0.215 0.317 0.256 0.134 0.042 

FSV-FJ 5.53 2.18 1.89 1.63 0.95 0.310 0.320 0.150 0.160 0.030 

N 

Min 

Median 

Max 

eSD 

eCV 

Npast 

Medianpast 

SDpast 

NISTa 

NISTb 

NNIST 

Mean 

Srep 

Shet 

Sanl 

SNIST 

NAV 

NAU 

25 25 25 25 25 

4.72 1.79 1.56 1.37 0.95 

6.18 2.30 2.01 1.78 1.21 

16.17 5.81 4.36 4.15 2.53 

0.48 0.20 0.18 0.16 0.11 

8 9 9 9 9 

26 29 29 25 22 

6.03 2.38 1.85 1.71 1.22 

0.65 0.25 0.17 0.15 0.17 

3 4 4 4 4 

6.04 2.06 1.76 1.62 1.12 

0.22 0.06 0.09 0.05 0.03 

0.02 0.15 0.10 0.08 0.15 

0.19 0.02 0.27 0.05 0.06 

0.29 0.17 0.30 0.11 0.17 

7 7 7 7 7 

0.313 0.084 0.106 0.153 2.15 

0.432 0.111 0.118 0.196 3.14 

0.757 0.748 0.310 0.340 3.39 

0.089 0.031 0.018 0.053 0.37 

21 28 15 27 12 

10 6 6 7 

0.550 0.121 0.152 0.165 

0.249 0.048 0.062 0.038 

0 

3 2 2 2 4 

0.337 0.072 0.128 0.136 2.30 

0.023 0.004 0.008 0.009 0.08 

0.010 0.001 0.011 0.011 0.10 

0.093	 0.34 

0.096 0.004 0.014 0.014 0.36 

32 

0.233 

0.366 

0.485 

0.030 

8 

35 

0.369 

0.051 

3 

0.349 

0.005 

0.001 

0.031 

0.032 

32 

0.320 

0.499 

0.691 

0.047 

9 

33 

0.515 

0.077 

2 

0.402 

0.015 

0.008 

0.017 

32 

0.150 

0.352 

0.483 

0.034 

10 

33 

0.307 

0.068 

2 

0.273 

0.009 

0.006 

0.011 

32 

0.119 

0.169 

0.337 

0.015 

9 

34 

0.171 

0.022 

2 

0.139 

0.005 

0.007 

0.008 

31 

0.030 

0.057 

0.110 

0.009 

16 

35 

0.056 

0.017 

2 

0.046 

0.007 

0.001 

0.007 

14 14 14 14 14 

0.215 0.292 0.180 0.082 0.021 

0.313 0.442 0.316 0.144 0.050 

0.342 0.481 0.338 0.165 0.076 

0.034 0.036 0.030	 0.016 0.005 

11 8 9 11 10 

13 17 17 12 11 

0.325 0.470 0.287 0.158 0.056 

0.047 0.061 0.042 0.020 0.012 

3 4 4 2 1 

0.295 0.399 0.268 0.153 0.048 

0.005 0.010 0.012 0.003 0.003 

0.008 0.026 0.003 0.009 0.000 

0.069 0.076 0.024 

0.069 0.081 0.027 0.010 0.003 

5.90 2.08 1.96 1.66 1.08 

6.18 2.04 1.57 1.58 1.11 

0.268 nq nq nq 2.06 

0.403 0.072 0.128 0.136 2.50 

0.327 0.402 0.273 0.139 0.046 

0.371 >0.453 >0.285 >0.153 >0.048 

0.246 0.345 0.251 <0.139 <0.046 

0.343 0.453 0.285 0.153 0.048 

6.11 2.18 1.89 1.70 1.16 

0.52 0.29 0.35 0.22 0.18 

0.385 0.091 0.123 0.166 2.72 

0.117 0.042 0.027 0.068 0.70 

0.358 

0.054 

0.450 

0.097 

0.313 

0.075 

0.154 

0.034 

0.052 

0.014 

0.304 0.420 0.292 

0.070 0.087 0.048 

0.148 

0.018 

0.049 

0.009 

All Lab Report C3 Page 2 / 8 
 

 

Round Robin XLIX Laboratory Results 

All Values in μg/mL 

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

Lab 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 

FSV-BA 0.033 0.023 0.010 0.011 nd 0.014 0.020 0.029 0.027 0.028 0.62 0.274 0.425 0.60 0.227 

FSV-BB 0.028 0.020 0.018 0.003 0.019 0.009 0.018 0.029 0.020 0.017 0.59 0.260 0.421 0.57 0.237 

FSV-BD 

FSV-BE 

FSV-BF 0.015 0.020 0.031 0.030 0.035 0.60 0.209 0.377 0.53 0.196 

FSV-BG 0.023 0.034 0.043 0.031 0.030 0.60 0.316 0.415 0.52 0.234 

FSV-BH 0.033 0.024 0.022 0.010 nd 0.011 0.015 0.027 0.024 0.024 0.54 0.236 0.376 0.52 0.205 

FSV-BI 0.014 0.022 0.028 0.031 0.031 0.44 0.204 0.338 0.43 0.175 

FSV-BJ 0.015 0.028 0.042 0.034 0.028 0.49 0.186 0.330 0.45 0.189 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.032 0.026 0.024 0.004 nd 0.001 0.011 0.023 0.018 0.025 0.48 0.217 0.363 0.47 0.218 

FSV-BO 0.014 0.018 0.033 0.032 0.029 0.49 0.211 0.395 0.27 0.248 

FSV-BP 0.009 0.015 0.026 0.022 nd 0.54 0.416 0.362 0.27 nd 

FSV-BQ 

FSV-BR 

FSV-BS nd >0.009 >0.015 >0.017 >0.012 nd 0.009 0.015 0.017 0.012 0.48 0.278 0.330 0.42 0.276 

FSV-BT 0.024 0.019 0.018 0.008 0.003 0.010 0.017 0.027 0.026 0.026 0.43 0.198 0.311 0.42 0.190 

FSV-BU 0.020 0.021 0.035 0.032 0.034 0.57 0.134 0.346 0.57 0.142 

FSV-BV 0.006 0.012 0.021 0.017 0.019 0.40 0.181 0.299 0.40 0.173 

FSV-BW >0.020 >0.016 0.020 0.016 <0.015 <0.015 <0.015 0.53 0.230 0.350 0.50 0.240 

FSV-BX 0.019 0.023 0.038 0.037 0.035 

FSV-CB 0.010 0.016 0.026 0.022 0.025 0.45 0.200 0.305 0.44 0.177 

FSV-CC 

FSV-CD 0.012 0.018 0.032 0.023 0.027 0.60 0.231 0.338 0.41 0.158 

FSV-CE 

FSV-CF 

FSV-CG 0.034 0.026 0.025 0.010 0.007 0.016 0.021 0.036 0.030 0.029 0.54 0.233 0.381 0.50 0.207 

FSV-CH 0.013 0.018 0.038 0.023 0.029 0.40 0.196 0.297 0.40 0.179 

FSV-CI
 

FSV-CL
 0.013 0.020 0.027 0.026 0.022 0.49 0.230 0.324 0.46 0.180 

FSV-CR 

FSV-CV 0.115 0.017 0.032 0.203 0.015 1.15 0.487 0.632 1.09 0.314 

FSV-CW 0.034 0.027 0.024 0.010 0.004 >0.013 >0.021 >0.031 >0.025 >0.028 0.013 0.021 0.031 0.025 0.028 0.46 0.203 0.339 0.45 0.200 

FSV-CZ 

FSV-DB 0.65 0.280 0.440 0.61 0.270 

FSV-DD 

FSV-DF 

FSV-DI 

FSV-DQ 0.025 0.017 0.045 0.042 0.049 0.89 0.149 0.594 1.07 0.361 

FSV-DR 

FSV-DU 

FSV-EH 0.058 0.044 0.041 0.023 0.022 0.008 0.013 0.026 0.018 0.020 0.51 0.224 0.363 0.49 0.208 

FSV-EQ 0.012 0.008 0.008 0.003 nd 0.008 0.012 0.024 0.019 0.017 0.51 0.236 0.364 0.54 0.213 

FSV-FB 0.111 0.073 0.057 0.044 0.031 >0.003 >0.012 >0.020 >0.014 >0.018 0.003 0.012 0.020 0.014 0.018 0.46 0.242 0.396 0.58 0.229 

FSV-FJ 0.010 nq 0.020 0.020 0.020 

N 

Min 

Median 

Max 

eSD 

eCV 

Npast 

Medianpast 

SDpast 

NISTa 

NISTb 

NNIST 

Mean 

Srep 

Shet 

Sanl 

SNIST 

10 10 10 10 6 

0.012 0.008 0.008 0.003 0.003 

0.033 0.025 0.023 0.010 0.013 

0.111 0.073 0.057 0.044 0.031 

0.004 0.005 0.008 0.006 0.013 

13 21 33 63 103 

10 11 11 7 6 

0.037 0.024 0.020 0.012 0.006 

0.019 0.009 0.007 0.006 0.004 

24 

0.001 

0.013 

0.115 

0.005 

38 

25 

0.013 

0.005 

23 

0.011 

0.018 

0.034 

0.004 

25 

28 

0.022 

0.007 

1 

0.012 

0.000 

0.000 

0.000 

24 

0.020 

0.029 

0.045 

0.005 

17 

29 

0.030 

0.006 

24 

0.017 

0.026 

0.203 

0.008 

29 

27 

0.027 

0.012 

2 

0.034 

0.001 

0.001 

0.001 

23 

0.015 

0.027 

0.049 

0.006 

22 

28 

0.028 

0.006 

2 

0.028 

0.001 

0.001 

0.001 

3 4 

0.003 0.009 

0.013 0.014 

0.020 0.021 

0.005 

35 

0 0 

1 2 

0.017 0.014 

0.000 0.004 

0.000 0.001 

0.000 0.004 

3 

0.015 

0.020 

0.031 

0 

2 

0.021 

0.003 

0.001 

0.004 

3 

0.014 

0.017 

0.025 

0 

2 

0.018 

0.001 

0.002 

0.002 

3 

0.012 

0.018 

0.028 

0 

1 

0.023 

0.000 

0.000 

0.000 

27 27 27 27 26 

0.40 0.134 0.297 0.27 0.142 

0.51 0.230 0.363 0.49 0.208 

1.15 0.487 0.632 1.09 0.361 

0.09 0.044 0.049 0.10 0.042 

18 19 13 21 20 

28 29 29 29 29 

0.50 0.229 0.330 0.46 0.197 

0.11 0.049 0.086 0.10 0.050 

1 2 2 2 1 

0.40 0.185 0.296 0.47 0.184 

0.05 0.008 0.019 0.02 0.038 

0.00 0.013 0.003 0.04 0.000 

0.05 0.016 0.019 0.05 0.038 

0.080 0.057 0.023 

0.028 nd nd 

nq 

nd 

nq 

nd 

nq nq nq >0.034 >0.028 

>0.017 >0.014 >0.021 >0.018 >0.023 

nq nq 

0.017 0.014 

nq 

0.021 

0.034 

0.018 

0.028 

0.023 0.40 0.185 0.296 0.47 0.184 

NAV 

NAU 

0.033 0.025 0.023 0.010 0.013 0.015 0.029 0.030 0.028 

0.012 0.009 0.008 0.006 0.005 0.008 0.010 0.011 0.009 

0.45 0.208 0.329 0.48 0.196 

0.13 0.063 0.093 0.10 0.053 

All Lab Report C4 Page 3 / 8 
 

 

Round Robin XLIX Laboratory Results 

All Values in μg/mL 

trans-Lycopene Total β-Cryptoxanthin Total α-Cryptoxanthin		 Total Lutein 

Lab 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273
 

FSV-BA
 0.293 0.151 0.220 0.267 0.121 0.050 0.064 0.071 0.067 0.069
 

FSV-BB
 0.235 0.128 0.186 0.219 0.101 0.039 0.049 0.056 0.052 0.055 0.016 0.024 0.025 0.019 0.031 0.062 0.101 0.097 0.118 0.064 

FSV-BD 

FSV-BE 

FSV-BF 0.036 0.037 0.043 0.043 0.041 

FSV-BG 0.322 0.172 0.221 0.256 0.126 0.032 0.042 0.042 0.044 0.033 0.065 0.058 0.074 0.077 0.060 

FSV-BH 0.061 0.064 0.078 0.083 0.080 0.040 0.068 0.063 0.085 0.054 

FSV-BI 0.042 0.061 0.066 0.059 0.066 0.070 0.106 0.113 0.143 0.082 

FSV-BJ 0.034 0.043 0.054 0.044 0.055 0.062 0.082 0.090 0.119 0.086 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.217 0.119 0.191 0.207 0.117 0.035 0.056 0.065 0.052 0.066 0.009 0.023 0.024 0.014 0.033 0.049 0.088 0.084 0.104 0.068 

FSV-BO 0.038 0.049 0.057 0.051 0.059 0.059 0.111 0.108 0.205 0.080 

FSV-BP 0.035 0.064 0.059 0.064 0.032 

FSV-BQ 

FSV-BR 

FSV-BS 0.243 0.103 0.122 0.156 0.103 0.042 0.051 0.052 0.064 0.058 nd 0.033 0.033 0.052 0.023 

FSV-BT 0.188 0.088 0.138 0.178 0.084 0.055 0.063 0.064 0.066 0.077 0.033 0.035 0.035 0.039 0.043 0.072 0.105 0.115 0.119 0.095 

FSV-BU 0.044 0.056 0.060 0.056 0.062
 

FSV-BV
 0.021 0.029 0.033 0.030 0.032 

FSV-BW 

FSV-BX 0.220 0.111 0.170 0.199 0.100 0.039 0.051 0.054 0.051 0.051 0.057 0.097 0.092 0.118 0.069 

FSV-CB 0.041 0.046 0.054 0.049 0.053 0.048 0.074 0.084 0.133 0.063 

FSV-CC 

FSV-CD 0.039 0.045 0.054 0.054 0.048 

FSV-CE 

FSV-CF 

FSV-CG 0.283 0.139 0.208 0.245 0.116 0.047 0.048 0.058 0.058 0.051 0.082 0.119 0.115 0.138 0.099 

FSV-CH 

FSV-CI
 

FSV-CL
 0.047 0.059 0.050 0.043 0.056 0.037 0.041 0.034 0.029 0.042 

FSV-CR 

FSV-CV 

FSV-CW 0.204 0.106 0.155 0.185 0.101 0.042 0.045 0.053 0.051 0.052 0.020 0.023 0.027 0.022 0.029 >0.048 >0.073 >0.073 >0.093 >0.056 

FSV-CZ 

FSV-DB 0.045 0.063 0.060 0.056 0.072 

FSV-DD 

FSV-DF 

FSV-DI 0.342 0.150 0.217 0.304 0.109 0.038 0.064 0.063 0.086 0.052 

FSV-DQ 0.049 0.067 0.087 0.093 0.107 0.047 0.207 0.089 0.072 0.033 

FSV-DR 

FSV-DU 

FSV-EH 0.215 0.107 0.164 0.197 0.089 0.041 0.052 0.059 0.056 0.062 >0.051 >0.080 >0.077 >0.092 >0.061 

FSV-EQ 0.037 0.045 0.049 0.051 0.052
 

FSV-FB
 0.413 0.208 0.345 0.503 0.196 0.038 0.062 0.063 0.057 0.067 0.052 0.063 0.065 0.100 0.044 

FSV-FJ 

N 

Min 

Median 

Max 

eSD 

eCV 

Npast 

Medianpast 

SDpast 

NISTa 

NISTb 

NNIST 

Mean 

Srep 

Shet 

Sanl 

SNIST 

NAV 

NAU 

12 12 12 12 12 

0.188 0.088 0.122 0.156 0.084 

0.239 0.124 0.189 0.213 0.106 

0.413 0.208 0.345 0.503 0.196 

0.058 0.028 0.044 0.050 0.015 

24 23 24 23 14 

14 12 12 8 5 

0.260 0.135 0.165 0.250 0.114 

0.061 0.019 0.017 0.039 0.031 

25 25 25 25 

0.021 0.029 0.033 0.030 

0.041 0.051 0.057 0.054 

0.061 0.067 0.087 0.093 

0.006 0.012 0.008 0.007 

14 23 14 13 

24 29 29 22 

0.044 0.052 0.054 0.054 

0.010 0.010 0.013 0.016 

1 4 4 2 

0.042 0.047 0.067 0.065 

0.000 0.001 0.010 0.014 

0.000 0.007 0.004 0.003 

0.025 0.003 

0.000 0.026 0.011 0.015 

25 

0.032 

0.056 

0.107 

0.012 

21 

22 

0.060 

0.016 

2 

0.036 

0.003 

0.002 

0.003 

5 5 5 5 5 

0.009 0.023 0.024 0.014 0.029 

0.020 0.024 0.027 0.022 0.033 

0.037 0.041 0.035 0.039 0.043 

0.016 0.001 0.004 0.010 0.006 

82 6 16 47 18 

6 7 7 

0.019 0.030 0.026 

0.010 0.004 0.007 

0 0 

1 2 2 2 1 

0.030 0.047 0.047 0.038 0.036 

0.000 0.001 0.009 0.006 0.007 

0.000 0.002 0.002 0.001 0.000 

0.000 0.002 0.009 0.007 0.007 

14 

0.038 

0.058 

0.082 

0.014 

25 

16 

0.065 

0.026 

2 

0.055 

0.001 

0.006 

0.006 

15 15 15 15 

0.033 0.033 0.052 0.023 

0.088 0.089 0.118 0.064 

0.207 0.115 0.205 0.099 

0.030	 0.029 0.031 0.024 

34 32 26 37 

16 16 14 8 

0.092 0.083 0.125 0.079 

0.017 0.013 0.016 0.014 

2 2 2 2 

0.101 0.110 0.137 0.075 

0.010 0.005 0.004 0.004 

0.002 0.002 0.003 0.000 

0.010 0.006 0.005 0.004 

nq 0.029 0.065 nq 0.036 

0.042 0.064 0.069 0.065 >0.045 0.030 0.047 0.047 0.038 0.036 

0.055 0.101 0.110 0.137 0.075 

>0.054 >0.067 >0.068 >0.091 >0.050 

0.239 0.124 0.189 0.213 0.106 

0.058 0.028 0.044 0.050 0.018 

0.041 0.049 0.062 0.060 

0.010 0.026 0.015 0.017 

0.046 

0.020 

0.025 0.035 0.037 0.030 0.035 

0.018 0.016 0.017 0.015 0.007 

0.057 

0.015 

0.094 

0.031 

0.099 

0.032 

0.127 

0.033 

0.069 

0.025 

All Lab Report C5 Page 4 / 8 
 

 

Round Robin XLIX Laboratory Results 

All Values in μg/mL 

Lab 

FSV-BA
 

FSV-BB
 

FSV-BD
 

FSV-BE
 

FSV-BF
 

FSV-BG
 

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-CB
 

FSV-CC
 

FSV-CD
 

FSV-CE
 

FSV-CF
 

FSV-CG
 

FSV-CH
 

FSV-CI
 

FSV-CL
 

FSV-CR
 

FSV-CV
 

FSV-CW 

FSV-CZ 

FSV-DB 

FSV-DD 

FSV-DF 

FSV-DI 

FSV-DQ 

FSV-DR 

FSV-DU 

FSV-EH 

FSV-EQ 

FSV-FB 

FSV-FJ 

N 

Min 

Median 

Max 

eSD 

eCV 

Npast 

Medianpast 

SDpast 

NISTa 

NISTb 

NNIST 

Mean 

Srep 

Shet 

Sanl 

SNIST 

NAV 

NAU 

269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 

0.051 0.048 0.041 0.054 0.035 

0.019 0.012 0.020 0.018 0.020 

0.020 0.033 0.023 0.025 0.035 

0.026 0.042 0.033 0.038 0.039 

0.017 0.027 0.022 0.023 0.032 

0.020 0.024 0.018 0.019 0.027 

>0.028 >0.033 >0.038 >0.044 >0.041 0.028 0.033 0.038 0.044 0.041 

0.022 0.034 0.024 0.026 0.034 

0.020 0.035 0.033 0.007 0.036 

0.018 0.025 0.024 0.034 0.022 

0.048 0.073 0.073 0.093 0.056 0.023 0.034 0.025 0.026 0.033 

0.019 0.064 0.017 0.008 0.025 

0.051 0.080 0.077 0.092 0.061 0.023 0.036 0.028 0.029 0.033 

0.020 0.037 0.016 0.012 0.030 

trans-Lutein 

2 2 2 2 2 13 

0.048 0.073 0.073 0.092 0.056 0.017 

0.050 0.077 0.075 0.093 0.059 0.020 

0.051 0.080 0.077 0.093 0.061 0.051 

0.002 

12 

0 0 0 0 0 12 

0.027 

0.010 

1 2 2 2 1 

0.054 0.067 0.068 0.091 0.050 

0.009 0.004 0.005 0.004 0.001 

0.000 0.005 0.003 0.005 0.000 

0.009 0.006 0.006 0.007 0.001 

0.020 

0.006 

Total Zeaxanthin 

13 13 13 

0.012 0.016 0.007 

0.034 0.024 0.025 

0.064 0.041 0.054 

0.010 0.007 0.010 

31 28 42 

15 15 11 

0.035 0.027 0.032 

0.009 0.005 0.012 

2 2 

0.020 0.015 

0.001 0.001 

0.000 0.003 

0.001 0.003 

0.034 0.022 0.020 

0.010 0.007 0.012 

13 

0.020 

0.033 

0.039 

0.004 

13 

8 

0.035 

0.008 

2 

0.024 

0.001 

0.000 

0.001 

0.028 

0.011 

trans-Zeaxanthin 

1 1 1 1 1 

0.028 0.033 0.038 0.044 0.041 

0 0 0 0 0 

1 2 2 2 1 

0.029 0.036 0.026 0.034 0.033 

0.000 0.002 0.002 0.004 0.003 

0.000 0.004 0.003 0.005 0.000 

0.000 0.004 0.004 0.007 0.003 

0.054 0.067 0.068 0.091 0.050 

nq nq 0.020 0.015 0.024 

>0.029 >0.036 >0.026 >0.034 >0.033 0.029 0.036 0.026 0.034 0.033 

All Lab Report C6 Page 5 / 8 
 

C7 

Round Robin XLIX Laboratory Results 

All Values in μg/mL 

Total Lutein&Zeaxanthin Coenzyme Q10 Phylloquinone (K1) x1000 

Lab 269 270 271 272 273 269 270 271 272 273 269 270 271 272 273 

FSV-BA 0.106 0.156 0.158 0.182 0.132 

FSV-BB 0.113 0.149 0.138 0.172 0.099 

FSV-BD 

FSV-BE 0.38 0.91 0.38 0.42 0.16 

FSV-BF 0.107 0.157 0.153 0.203 0.138 

FSV-BG 0.089 0.073 0.102 0.101 0.087 

FSV-BH 0.060 0.101 0.086 0.110 0.089 

FSV-BI 0.096 0.141 0.145 0.187 0.130 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.060 0.104 0.098 0.118 0.087 

FSV-BO 0.079 0.134 0.126 0.224 0.107 

FSV-BP 0.080 0.120 0.110 0.130 0.006 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.192 0.191 0.217 0.263 0.192 

FSV-BU 0.091 0.153 0.144 0.203 0.130 

FSV-BV 0.071 0.113 0.109 0.136 0.099 

FSV-BW 

FSV-BX 0.079 0.130 0.115 0.144 0.103 

FSV-CB 0.069 0.109 0.117 0.140 0.099 

FSV-CC 

FSV-CD 0.080 0.116 0.143 0.130 0.089 

FSV-CE 

FSV-CF 

FSV-CG 0.100 0.143 0.139 0.171 0.120 

FSV-CH 0.487 0.45 0.52 0.335 0.48 

FSV-CI 

FSV-CL 0.084 0.114 0.100 0.125 0.100 

FSV-CR 

FSV-CV 0.092 0.146 0.125 0.172 0.110 1.948 0.96 0.99 0.942 1.78 

FSV-CW >0.071 >0.107 >0.098 >0.119 >0.089 0.910 0.83 0.95 0.570 1.07 

FSV-CZ 0.790 0.94 1.10 0.540 1.00 

FSV-DB 0.098 0.129 0.115 0.152 0.120 

FSV-DD 

FSV-DF 

FSV-DI 0.855 0.72 0.79 0.493 0.85 0.68 1.37 0.53 0.47 nd 

FSV-DQ 0.066 0.271 0.106 0.080 0.058 

FSV-DR 

FSV-DU 

FSV-EH >0.074 >0.116 >0.105 >0.121 >0.094 

FSV-EQ 0.017 0.196 0.183 0.245 0.178 

FSV-FB 0.072 0.100 0.081 0.112 0.074 

FSV-FJ 

N 22 22 22 22 22 5 5 5 5 5 2 2 2 2 1 

Min 0.017 0.073 0.081 0.080 0.006 0.487 0.45 0.52 0.335 0.48 0.38 0.91 0.38 0.42 

Median 0.082 0.132 0.121 0.148 0.101 0.855 0.83 0.95 0.540 1.00 0.53 1.14 0.46 0.45 0.16 

Max 0.192 0.271 0.217 0.263 0.192 1.948 0.96 1.10 0.942 1.78 0.68 1.37 0.53 0.47 

eSD 0.020 0.030 0.030 0.047 0.024 0.096 0.16 0.22 0.070 0.22 

eCV 25 22 25 32 24 11 20 23 13 22 

Npast 22 29 29 22 21 0 0 0 0 0 0 0 0 0 0 

Medianpast 0.089 0.134 0.114 0.154 0.117 

SDpast 0.016 0.027 0.017 0.034 0.018 

NISTa >0.055 >0.101 0.130 0.151 0.098 

NISTb >0.083 >0.103 >0.093 >0.125 >0.082 

NNIST 1 2 4 4 3 

Mean 0.077 0.103 0.112 0.138 0.090 

Srep 0.000 0.005 0.007 0.008 0.004 

Shet 0.000 0.009 0.005 0.000 0.000 

Sanl 0.026 0.019 0.011 

SNIST 0.000 0.010 0.028 0.020 0.012 

NAV 0.080 0.118 0.117 0.143 0.096 

NAU 0.021 0.036 0.030 0.048 0.026 

All Lab Report Page 6 / 8 
 

 

 

 

 

 

Round Robin XLIX Laboratory Results
 

Analytes Reported By One Laboratory
 

Values in μg/mL 

Term 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NIST 

NAV 

NAU 

NNIST 

MeanNIST 

Srep 

Shet 

Sanl 

SNIST 

nd 

nq 

<x 

>x 

italics

Analyte Code 269 270 271 272 273 

25-hydroxyvitamin D FSV-BN 0.01 0.06 0.02 0.02 0.01 

3'-dehydro-Lutein FSV-BH 0.04 0.03 0.04 0.06 0.03 

Phytofluene FSV-CL 0.059 0.014 0.042 0.078 0.024 

Total cis-Lutein&Zeaxanthin FSV-BT 0.092 0.052 0.064 0.100 0.056 

trans-Lutein&Zeaxanthin FSV-BT 0.100 0.138 0.153 0.163 0.136 

trans-β-Cryptoxanthin NISTb 0.040 0.056 0.059 0.053 0.045 

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

 Adjusted median absolute deviation from the median of the non-NIST results

 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)
 

 Mean of NIST results

 NIST Assigned Value

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

= Median for analytes reported by ≥ 5 labs but not NIST 

NIST Assigned Uncertainty: √(S 2 + Sbtw 2)

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

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

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

 Number of total vials analyzed in duplicate by NIST analysts

 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 

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

 Detected but not quantitatively determined

 Concentration less than the limit of quantification, x

 Concentration greater than x

 Not explicitly reported but calculated by NIST from reported values

All Lab Report 

C8

Page 7 / 8 
 

 

 

 

 

 

Lab 

FSV-BA 

FSV-BB 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

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-CB 

FSV-CC 

FSV-CD 

FSV-CE 

FSV-CF 

FSV-CG 

Round Robin XLIX Laboratory Results 

Comparability Summary 

TR aT g/bT bC tbC aC TLy TbX TLu TZ L&Z 

1 1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 2 2 

1 1 1 

1 1 1 1 2 

1 1 1 2 1 1 1 

1 1 1 1 2 1 1 1 2 

1 1 1 1 1 1 1 2 1 3 1 

1 1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 1 

1 2 

3 4 

1 2 

1 1 2 1 1 2 1 1 1 1 

1 1 1 1 2 1 2 

1 1 1 1 3 1 1 

1 1 2 1 

1 2 2 

1 3 3 2 1 1 2 1 1 

2 1 1 1 1 1 1 1 1 

1 1 1 1 1 2 1 1 1 

2 1 1 1 1 1 2 2 4 

1 1 1 1 2 1 

1 1 1 1 2 1 1 1 

1 1 1 1 1 1 1 1 1 

1 1 

1 1 1 1 1 1 1 

1 1 1 1 

1 1 1 

1 2 1 1 1 1 1 1 2 1 

Label

Lab 

TR 

aT 

g/bT

bC 

tbC 

aC 

TLy 

TbX 

TLu 

TZ 

L&Z

n 

% 1 

% 2 

% 3 

% 4 

 Definition 

 Participant code 

 Total Retinol 

α-Tocopherol 

 γ/β-Tocopherol 

 Total β-Carotene 

 trans-β-Carotene 

 Total α-Carotene 

 Total Lycopene 

Total β-Cryptoxanthin 

 Total Lutein 

 Total Zeaxanthin 

 Total Lutein & Zeaxanthin 

 number of participants providing quantitative data 

 Percent of CS = 1 (within 1 SD of medians) 

 Percent of CS = 2 (within 2 SD of medians) 

 Percent of CS = 3 (within 3 SD of medians) 

 Percent of CS = 4 (3 or more SD from medians) 

“Comparability Score” 















− 





 

The Comparability Score (CS) summarizes your measurement 

performance for a given analyte relative to the consensus 

medians in this study. CS is the average distance (in units of 

standard deviation) of your measurement performance 

characteristics from the consensus performance. CS is 

calculated when the number of quantitative values you reported, 

Nyou, is at least two and at least six participants reported 

quantitative values for the analyte. 

We define CS as follows: 

MINIMUM 4,INTEGER 1 

you Youi Median i 

i i 

FSV-CH 2 1 1 2 1 1 1 CS =

N − 

+ C2 + AP2 



 





 FSV-CI 2 1 2 1 1 N 

you

∑ 

= 









∑ 

= NAU i 1 i 

You 

i 1 

FSV-DD 1 NAU = NIST Assigned Uncertainty 

FSV-DF 1 

FSV-DI 1 1 2 1 1 1 For further details, please see 

FSV-CL 2 2 2 1 1 1 1 

FSV-CR 1 1 C = Concordance = 

N FSV-CV 4 2 4 2 4 4 you 

2 FSV-CW 2 1 1 1 1 1 1 1 1 N −Median 

NAU i 

1 

FSV-CZ 1 4 2 

AP = Apparent Precision = FSV-DB 1 1 1 2 1 2 3 you 

FSV-DQ 

FSV-DR 

4 4 4 2 4 2 3 3 

1 2 1 

Duewer DL, Kline MC, Sharpless KE, Brown Thomas J, Gary 

KT. Micronutrients Measurement Quality Assurance 

Program: Helping participants use interlaboratory comparison 

FSV-DU 1 2 2 2 exercise results to improve their long-term measurement 

FSV-EH 1 1 1 1 1 1 1 1 1 1 1 performance. Anal Chem 1999;71(9):1870-8. 

FSV-EQ 1 3 1 1 1 1 1 

FSV-FB 3 1 1 2 2 1 1 1 1 1 

FSV-FJ 1 1 1 2 1 

NISTa 1 1 1 1 1 1 1 1 1 1 

NISTb 1 1 1 1 1 1 1 1 1 1 1 

n 48 46 27 38 16 30 28 27 19 16 26 

TR aT g/bT bC tbC aC TLy TbX TLu TZ L&Z 

% 1 81 74 78 79 75 77 79 89 79 69 73 

% 2 13 17 15 16 19 20 11 11 16 25 15 

% 3 4 2 0 3 6 0 4 0 5 6 8 

% 4 2 7 7 3 0 3 7 0 0 0 4 

All Lab Report C9Page 8 / 8 
 

Appendix D. Representative “Individualized Report” for RR49 

Each participant in RR49 received an “Individualized Report” reflecting their reported 

results. Each report included a detailed analysis for analytes that were assayed by at least 

five participants. The following analytes met this criterion in RR49: 

• Total Retinol 

• trans-Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ/β-Tocopherol 

• δ-Tocopherol 

• Total β-Carotene 

• trans-β-Carotene 

• Total cis-β-Carotene 

• Total α-Carotene 

• Total Lycopene 

• trans-Lycopene 

• Total β-Cryptoxanthin 

• Total α-Cryptoxanthin 

• Total Lutein 

• Total Zeaxanthin 

• Total Lutein & Zeaxanthin 

• Coenzyme Q10 

The following 13 pages are the “Individualized Report” for the analytes evaluated by 

participant FSV-BA. 

D1
 

 Set 1 of 49

Individualized Round Robin XLIX Report: FSV-BA 

Summary 

Serum 269 Serum 270 Serum 271 Serum 272 

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

Total Retinol 1.252 0.979 36 0.688 0.630 36 0.495 0.449 36 0.564 0.491 36 

Retinyl Palmitate 0.07 0.03 13 nd 0.0 12 0.1 0.1 14 0.12 0.07 14 

α-Tocopherol 28.85 26.88 44 6.15 5.71 44 7.21 6.72 44 8.11 7.52 44 

γ/β-Tocopherol 6.423 6.124 25 2.292 2.179 25 1.961 1.890 25 1.755 1.705 25 

Total β-Carotene 0.347 0.358 32 0.480 0.452 32 0.331 0.314 32 0.165 0.154 32 

trans-β-Carotene 0.316 0.305 14 0.460 0.420 14 0.323 0.288 14 0.155 0.150 14 

Total cis-β-Carotene 0.033 0.035 10 0.023 0.025 10 0.010 0.022 10 0.011 0.011 10 

Total α-Carotene 0.014 0.013 24 0.020 0.015 23 0.029 0.030 24 0.027 0.030 24 

Total Lycopene 0.624 0.465 27 0.274 0.206 27 0.425 0.329 27 0.598 0.484 27 

trans-Lycopene 0.293 0.259 12 0.151 0.134 12 0.220 0.197 12 0.267 0.232 12 

Total β-Cryptoxanthin 0.050 0.041 25 0.064 0.049 25 0.071 0.062 25 0.067 0.060 25 

Total Lutein&Zeaxanthin 0.106 0.082 22 0.156 0.118 22 0.158 0.117 22 0.182 0.143 22 

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
 

nd : Not detected
 

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: 

 Individualized Report 
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

Total Retinol 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 2 / 13 

D3
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

Retinyl Palmitate 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

Median (50%) 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 3 / 13 

D4
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

α-Tocopherol 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 4 / 13 

D5
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

γ/β-Tocopherol 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 5 / 13 

D6
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

Total β-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 6 / 13 

D7
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

trans-β-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

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

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 7 / 13 

D8
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

Total α-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 8 / 13 

D9
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

Total Lycopene 

Apparent Precision, SD 

[Analyte], μg/mL 

Your [Analyte], μg/mL

193254255269267270271266223225228272203273

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

Median (50%) 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 9 / 13 

D10
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

trans-Lycopene 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

Long-term Precision, SD 

NIST, this RR 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 10 / 13 

D11
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

Total β-Cryptoxanthin 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

NIST, this RR Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, >x, this RR 

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 11 / 13 

D12
 

 Set 1 of 49

Individualized RR XLIX Report: FSV-BA 

Total Lutein&Zeaxanthin 

Apparent Precision, SD 

[Analyte], μg/mL 

193254255269267270271266223225228272203273

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

Long-term Precision, SD 

Median (50%) 

Concordance, SD 

3rd Quartile (75%) 

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

1st Quartile (25%) 

You, >x, past RRs You, past RRs Others, this RR 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Serum History Comments 

#269 #193 RR30 3/94, #254 RR45 3/99, #255 RR46 6/99 Lyophilized 

#270 Same pool as #267 (lq fz) RR48 9/00 Lyophilized 

#271 Same pool as #266 (ly) RR48 9/00 Fresh frozen 

#272 #223 & #225 RR38 9/96, #228 RR39 3/97 Lyophilized 

#273 #203 RR33 3/95 Lyophilized 

 Individualized Report Page 12 / 13 

D13
Set 1 of 49 

Individualized Round Robin XLIX Report: FSV-BA
 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total β-Carotene 

D14

Retinyl Palmitate γ/β-Tocopherol trans-β-Carotene To

Total Lycopene δ-Tocopherol Total cis-β-Carotene Total L

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

Individualized Report 
Appendix E. Shipping Package Inserts for RR14 

The following three items were included in each package shipped to an RR14 participant: 

•	 Cover letter 

•	 Protocol for Preparation and Analysis of the Ascorbic Acid Solid Control
 

Material
 

•	 Preparation and Validation of Ascorbic Acid Solid Control Material Datasheet 

•	 Analysis of Control Materials and Test Samples Datasheet 

The cover letter, preparation protocol, and the two datasheets were enclosed in a sealed 

waterproof bag along with the samples themselves. The packing list was placed at the 

top of the shipping box, between the cardboard covering and the foam insulation. 

We have no record, either electronic or hardcopy, of a packing list for the RR14 study. 

E1
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

January, 2001 

Dear Colleague: 

For the past 16 years the National Institute of Standards and Technology (NIST) has coordinated a 

Micronutrients Measurement Quality Assurance (QA) Program for laboratories making vitamin 

measurements in human serum. Frozen and/or freeze dried sera are sent to laboratories for analysis as an 

interlaboratory comparison exercise. Results are returned to NIST for data tabulation and evaluation. 

Value-assignment of the sample pools is based on the median of all the laboratory results, with 

confirmation based on measurements at NIST. We provide consultation and trouble-shooting regarding 

methods of analysis, and a certificate of participation in the QA program is issued at the end of each 

calendar year. We also host a micronutrient analysis QA workshop for fat-soluble vitamin, carotenoid, 

and ascorbic acid measurements in serum. 

The enclosed set of samples constitute the round robin exercise for vitamin C (Round Robin XIV) for 

2001. Four vials of frozen serum (test samples), and a vial of solid ascorbic acid (a control sample), are 

enclosed. Please follow the attached protocol when you analyze these samples. 

Report your results using the attached form by May 12, 2001. We also request that you send us a 

representative chromatogram from the analysis of each sample and indicate whether peak height or peak 

area was used in the calculation of the ascorbic acid concentration. Your results will be kept confidential. 

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

robin study. The summary report concerning this study will be provided near the end of June. 

Please mail your results to: 

Micronutrients Measurement Quality Assurance Program NIST
 

100 Bureau Drive, Stop 8392
 

Gaithersburg, MD 20899-8392
 

or Fax: 301.977 .0685 E-mail: sam.margolis@nist.gov 

If you have any questions or concerns please call me at 301.975.3137 or contact me by Fax or E-mail. 

Thank you for your participation and we look forward to receiving your results. 

Sincerely, 

Sam A. Margolis, Ph.D. 

Research Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

E2
 

 

 

 

 

 

 

 

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 180-220 mg of the solid ascorbic acid sample to 0.1 mg (if possible), dissolve it in 

5% MPA in a 100 mL volumetric flask, and dilute to the 100 mL mark. Weigh the 

amount of MPA solution that was added. This will be referred to as the Stock 

Solution. 

3.	 Prepare three dilute solutions of the Stock Solution as follows: 

Dilute Solution 1: Weigh 0.500 mL of the stock solution into a 100 mL volumetric 

flask. Then dilute with 5% MPA solution to 100 mL mark and weigh the amount of 

MPA solution that was added. 

Dilute Solution 2: Weigh 0.250 mL of the stock solution into a 100 mL volumetric 

flask. Then dilute with 5% MPA solution to 100 mL mark and weigh the amount of 

MPA solution that was added. 

Dilute Solution 3: Weigh 0.125 mL of the stock solution into a 100 mL volumetric 

flask. Then dilute with 5% MPA solution to 100 mL mark and weigh the amount of 

MPA solution that was added. 

4.	 Record the ultraviolet absorbance spectrum of Dilute Solution 1 against 5% MPA 

solution as the blank using paired cuvettes. Record the wavelength in the region of 240­

245 nm at which you observe the maximum absorbance and record the absorbance at that 

wavelength. 

5.	 Record the absorbance of the sample at 242, 243 and 244 nm. 

6.	 Measure the concentration of the ascorbic acid in all three dilute solutions and the 5% 

MPA diluent in duplicate along with the ampouled test samples using your usual 

methods. 

The purpose of measuring the absorbance at the wavelength maximum is to check the concentration 

of your sample. If your spectrophotometer is properly calibrated, the maximum absorbance should 

be between 243 and 244 nm. If the concentration is correct, the molar extinction coefficient (E1%) of 

ascorbic acid at this wavelength (using a cell with a 1 cm path length) should be close to 550 ± 30 

nm. The extinction coefficient of your solution can be calculated using the following equation: 

E1% dl/g·cm = Observed Absorbanceλmax 

(g AA/100 mL stock)(g stock in 100 mL dilute solution)

 (g AA stock solution) + (g MPA solution in 100 mL dilute solution 1) 

E3
 

 

The test samples are in sealed ampoules and were prepared by adding equal volumes of 10% 

metaphosphoric acid to spiked human serum. We have checked the samples for stability and 

homogeneity. Only the total ascorbic acid is stable. While these samples contain some 

dehydroascorbic acid, its content is variable. Therefore, only total AA should be reported. The test 

samples should be defrosted by warming at 20 °C for not more than 10 min otherwise some 

irreversible degradation may occur. 

Each test sample should contain between 0 and 100 μmol of ascorbic acid/L of solution. The total 

ascorbic acid in each ampoule should be measured in duplicate by the method(s) used in your 

laboratory. Please report your results in μg/L of sample. 

E4
 

 

 

 

 

 

 

 

 

 

 

 

 

 

REPORT OF ANALYSIS
 

NAME: 

ADDRESS: 

Telephone no.: 

Fax no.: 

Method of Analysis: 

Please note the type of method that you use. 

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 

Were samples frozen upon receipt? Yes No 

Date of Analysis: 

PREPARATION OF STOCK SOLUTION AND DILUTED SOLUTIONS 

STOCK SOLUTION 

Weight of ascorbic acid in the Stock Solution mg 

Weight of 5% MPA added to the 100 mL volumetric flask g 

DILUTE SOLUTION 1 

Weight of added stock solution (0.5 mL) mg 

Weight of 5% MPA added to the 100 mL volumetric flask g 

Absorbance of Dilute Solution 1 at 243 nm AU 

Absorbance of Dilute Solution 1 at 244 nm AU 

Wavelength of maximum absorbance nm 

Calculated molar absorptivity dL/g·cm 

E5
 

 

DILUTE SOLUTION 2 

Weight of added stock solution (0.25 mL)

Weight of 5% MPA added to the 100 mL volumetric flask

 mg 

g 

DILUTE SOLUTION 3 

Weight of added stock solution (0.125 mL)

Weight of 5% MPA added to the 100 mL volumetric flask

 mg 

g 

COMMENTS: (use other side if necessary) 

Mail by May 12, 2001 to: Fax: 301-977-0685 Micronutrients 

Micronutrients Measurement Quality Program E-mail: sam.margolis@nist.gov 

NIST, 100 Bureau Drive, Stop 8392 

Gaithersburg, MD 20899-8392 

E6
REPORT OF ANALYSIS
 

RESULTS (μmol/L of Sample)
 

DILUTE SOLUTION 1 

REPLICATE 1 μmol/L of dilute solution 1 

REPLICATE 2 μmol/L of dilute solution 1 

DILUTE SOLUTION 2 

REPLICATE 1 μmol/L of dilute solution 2 

REPLICATE 2 μmol/L of dilute solution 2 

DILUTE SOLUTION 3 

REPLICATE 1 μmol/L of dilute solution 3 

REPLICATE 2 μmol/L of dilute solution 3 

TEST SAMPLE #1 

REPLICATE 1 μmol/L of Sample 1 

REPLICATE 2 μmol/L of Sample 1 

TEST SAMPLE #2 

REPLICATE 1 μmol/L of Sample 2 

REPLICATE 2 μmol/L of Sample 2 

TEST SAMPLE #3 

REPLICATE 1 μmol/L of Sample 3 

REPLICATE 2 μmol/L of Sample 3 

TEST SAMPLE #4 

REPLICATE 1 μmol/L of Sample 4 

REPLICATE 2 μmol/L of Sample 4 

Mail by May 12, 2001 to: Fax: 301-977-0685 Micronutrients 

Micronutrients Measurement Quality Program E-mail: sam.margolis@nist.gov 

NIST, 100 Bureau Drive, Stop 8392 

Gaithersburg, MD 20899-8392 

E7
 

 

Appendix F. Final Report for RR14 

The following two 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 their previous distributions, 

if any, and 

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

participants. 

F1
UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899- NIST CENTENNIAL 

August 8, 2001 

Dear Colleague: 

Enclosed is the summary report of the results for Round Robin 14 (RR14) for the measurement of 

total ascorbic acid (T AA, ascorbic acid plus dehydroascorbic acid) in human serum. Included in 

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

for evaluating laboratory performance; and a summary of individual laboratory performance and 

interlaboratory accuracy and precision. As in previous reports, the estimated standard deviations 

(eSD) for the measurements are defined as 0.74 x interquartile range and the estimate 

coefficients of variation ( eCV) are defined as 100 x eSD/median. NIST data are not included in 

the statistical analysis. 

RR14 consists of four unknowns and one solid reference ascorbic acid for control solutions. 

Details regarding the samples can be found in the enclosed report. 

Data for evaluating laboratory performance in RR14 are provided in the comparability summary 

(Score Card) on page 1 of the "All Lab Report." Laboratory comparability is summarized as 

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

rated 4 are >3 standard deviations from the assigned value. 

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

analyze a unit of SRM 970, Vitamin C in Frozen Human Serum. SRM 970 can be purchased 

from the NIST SRM Office at phone: 301-975-6776; fax: 301-948-3730. If your measured 

values do not agree with the certified values, we suggest that you contact us for consultation. 

If you have any questions regarding this report, please contact David Duewer at 

david.duewer@nist.gov, phone: 301-975-3935 or Sam Margolis at sam.margolis@nist.gov; 

phone: 301-975-3137; fax: 301- 77-0685. 

&~ gnu} 

Analytical Chemistry Division 

Chemical Science and Tec, ology Laboratory 

~\,,~G Sam A. Margolis, Ph.D. 

Research Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

enclosure 

NISI 

F2
The NIST M2

QAP Vitamin C Round Robin 14 (RR14) report consists of 

Page “Individualized” Report 

1 Summarizes your reported values for the nominal 55 mmol/L control solution and the SRM 

970 Level 1 and 2 samples distributed in RR11 through RR14. 

2 Graphical summary of your RR 14 sample measurements. 

3 Graphical summary of your RR 14 control solution measurements. 

Page “All Lab” Report 

1 A listing of all results and statistics for Total Ascorbic Acid [TAA] in the RR14 samples 

and control solutions, the density of the 5% metaphosphoric acid (MPA) used to prepare the 

control solutions, the maximum absorbance reported between 243 nm and 245 nm for 

control solution #1, and the molar extinction coefficient. 

Samples. Four unknowns and a control material (ascorbic acid) were distributed in RR14. . Serum 

sample 1 was prepared (04/93) as sample 180a. Serum sample 2 was prepared (03/95) as sample 

188b. Sera samples 3 and 4 were prepared (05/98) as SRM 970, Level 1 and Level 2, respectively. 

Each serum sample was prepared by adding ascorbic acid to a serum pool that was depleted of 

ascorbic acid. 

Qualitative Observations. 

1)	 Too few sets of data have been returned to place a great deal of faith in the statistical summaries. If 

the program is to continue, the number of active participants must be increased. Suggestions are 

more than welcome! 

2)	 Many participants that reported “Not detected” for the “blank” (S14-2) sample had significantly nonzero intercepts for their external calibration curve. While these intercepts averaged about 1 μmol/L 

(the expected value for [TAA] in S14-2), they ranged as high as 13 μmol/L. Future exercises will 

request a “true” 5% MPA blank to help sort things out. 

3)	 Almost all participants correctly prepared the control solutions, although one participant appears to 

be using about 3% MPA and one about 10%. While the actual concentration of MPA in the nominal 

5% is not believed to be a critical parameter, these two participants reported the most extreme (low 

and high) molar extinction coefficients (E1%). These differences may influence calibrant purity 

corrections. 

4)	 Based upon 1% to 10% differences between reported and calculated E1% values, several participants 

based their calculations on volume rather than weight of stock solution delivered to control solution 

#1. In general, 0.500 g gravimetric measurements are more accurate than are 0.500 mL volumetric 

measurements. These differences may influence calibrant purity corrections. 

5)	 All participants are now reporting “reasonable” maximum absorbance values (ODmax) for the nominal 

55 μmol/L control solution #1. However, several participants report the location of maximal 

absorbance 1 nm to 2 nm offset from its nominal location of 244 nm. For most accurate results, 

spectrophotometers require periodic calibration of both their absorbance and wavelength axes. 

Quantitative Results. 

1)	 There is no sign of degradation (change in median [TAA] or increase in estimated standard 

deviation) in either SRM 970 Level 1 or Level 2 since their Certification in 1998. We will continue 

to periodically monitor these materials. 

F3
 

Appendix G. “All-Lab Report” for RR14 

The following single page is 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
Vitamin C 'Round Robin' 14
 

Laboratory Results
 

Total Ascorbic Acid [AA]nom ([AA]obs / [AA]calc) 

Lab Date Method 

G2

VC-MA 27/09/01 HPLC-EC 

VC-MB 26/03/01 AO-OPD, Cobas Fara 

VC-MC 02/05/01 HPLC-EC 

VC-ME 17/05/01 Cobas Bio Fluoro 

VC-MG 02/03/01 HPLC-UV-ionpair 

VC-MH 11/04/01 HPLC-Fluor OPD 

VC-MI 11/05/01 HPLC-UV 

VC-MO 15/02/01 HPLC-OPD 

VC-MQ 05/06/01 HPLC-EC 

VC-MR 13/03/01 HPLC-OPDA 

VC-MS 13/04/01 HPLC-EC 

VC-NH 23/04/01 HPLC-Fluor DAB 

VC-NK 27/04/01 24DNPH 

NIST 18/04/01 HPLC-EC 

S14:1 S14:2 S14:3 S14:4 

μmol/L solution 

20.0 0.00 7.8 26.0 

23.0 3.60 9.8 30.2 

26.0 6.32 11.4 33.0 

18.7 0.04 6.5 25.7 

18.0 0.00 9.1 27.5 

19.8 0.00 7.9 

29.3 0.00 31.4 

16.7 0.26 8.1 23.7 

18.7 1.49 7.9 24.8 

20.5 0.00 9.0 28.5 

19.0 0.00 7.9 25.7 

22.8 9.5 

36.7 0.00 12.2 21.0 

20.6 1.7 9.1 27.1 

14-Ctrl1 14-Ctrl2 14-Ctrl3 

Nominal μmol/L solution 

56.03 26.54 13.83 

57.54 29.32 15.38 

60.08 30.72 14.60 

54.03 26.83 13.42 

55.35 24.49 10.91 

54.95 27.59 13.97 

78.76 33.67 15.30 

54.47 29.50 15.45 

53.78 

57.17 28.67 15.25 

53.49 27.11 13.73 

58.25 36.12 23.63 

52.58 25.79 13.31 

D5%MPA 

g/mL 

1.034 

1.033 

1.032 

1.032 

1.032 

1.033 

1.035 

1.032 

1.043 

1.032 

1.031 

1.034 

1.029 

1.031 

N 13 12 12 11 12 11 11 13 

Average 22.2 1.0 8.9 27.0 57.8 29.1 15.0 1.033 

Min 16.7 0.00 6.5 21.0 53.49 24.49 10.91 1.029 

%25 18.7 0.00 7.9 25.2 54.36 26.97 13.78 1.032 

Median 20.0 0.00 8.6 26.0 55.69 28.67 14.60 1.032 

%75 23.0 0.57 9.6 29.4 57.72 30.11 15.34 1.034 

Max 36.7 6.32 12.2 33.0 78.76 36.12 23.63 1.043 

eSD 3.0 0.00 1.1 3.4 2.60 2.71 1.15 0.001 

eCV 15 13 13 5 9 8 0.1 

All Lab Report 
Appendix H. Representative “Individualized Report” for RR14 

Each participant in RR14 received an “Individualized Report” reflecting their reported 

results. The following three pages are the “Individualized Report” for participant 

“VC-MA”. 

H1
 

Set 1 of 13 

H2

Vitamin C 'Round Robin' 14 Report: Participant VC-MA 

Date Method RR Control 

09/23/98 HPLC-EC (Height) 11 55 μmol/L 

04/02/99 HPLC-EC (Height) 12 55 μmol/L 

09/17/01 HPLC-EC 13 55 μmol/L 

10/02/01 HPLC-EC (Height) 14 55 μmol/L, Crtl-1 

AA MPA Stock MPA 

mg g mg g Calc Obs 

[AA] μmol/L 

200.0 103.09 526.0 102.45 

215.0 103.10 517.1 102.52 

200.8 103.16 508.0 102.58 

200.3 103.23 510.0 102.31 

57.8 6.1 

61.1 53.1 

56.0 55.4 

56.1 57.1 

A243 A244 

OD OD 

0.0525 0.0527 

0.0721 0.0721 

0.5650 0.5232 

0.5409 0.5193 

[TAA] μmol/Lsample Grand Ave

RR Sample 

11 SRM Lv 1, A 

11 SRM Lv 1, B 

12 SRM Lv 1, A 

12 SRM Lv 1, B 

13 SRM Lv 1, S13-1 

14 SRM Lv 1, S14-3 

Mean SDrepea

7.8 0.3 

Rep1 Rep2 Factor Mean SDdup 

15.5 13.9 

14.0 14.5 

14.5 15.8 

16.1 15.1 

8.4 8.5 

8.0 7.8 

0.5 

0.5 

0.5 

0.5 

1.0 

1.0 

7.4 0.6 

7.1 0.2 

7.6 0.5 

7.8 0.3 

8.5 0.1 

7.9 0.2 

11 SRM Lv 2, A 50.7 47.7 

48.8 54.0 

49.5 45.9 

46.2 47.9 

27.6 27.7 

25.7 26.4 

0.5 

0.5 

0.5 

0.5 

1.0 

1.0 

24.6 1.1 

25.7 1.8 

23.9 1.3 

23.5 0.6 

27.7 0.1 

26.0 0.5 

25.6 1.1 

11 SRM Lv 2, B 

12 SRM Lv 2, A 

12 SRM Lv 2, B 

13 SRM Lv 2, S13-2 

14 SRM Lv 2, S14-4 

14 S14-1 (180B) 20.4 19.6 1.0 20.0 0.6 

14 S14-2 (188B) 1.0 0.0 0.0 

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: s

Individualized Report 
 

 

 

Set 1 of 13 

Vitamin C 'Round Robin' 14 Report: Participant VC-MA 

Total Ascorbic Acid: Samples 

S11loS12lo

S13-1

S14-3

S11hiS12hi

S13-2

S14-4 

S14-1 

S14-2 

[Total Ascorbic Acid], μmol/L 

Your [Total Ascorbic Acid], μmol/L

Median [Total Ascorbic Acid], μmol/L 

SRM 970 Level 1 SRM 970 Level 2 Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, RR 14 NIST, RR 14 

Median (50%) 

You, RR 11-13 Others, RR 11-13 

1st Quartile (25%) 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8. 

Sample Comments 

S14-1 Serum 180B, augmented 

S14-2 Serum 188B, no augmentation 

S14-3 SRM 970 Level 1 

S14-4 SRM 970 Level 2 

Individualized Report Page 1 / 3 

H3
 

 

 

 

Set 1 of 13 

Vitamin C 'Round Robin' 14 Report: Participant VC-MA 

Total Ascorbic Acid: Control Solutions 

11-Ctrl12-Ctrl13-Ctrl

14-Ctrl114-Ctrl214-Ctrl3 

[Total Ascorbic Acid], μmol/L 

Your [Total Ascorbic Acid], μmol/L

Median [Total Ascorbic Acid], μmol/L 

SRM 970 Level 1 SRM 970 Level 2 Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, RR 14 NIST, RR 14 

Median (50%) 

You, RR 11-13 Others, RR 11-13 

1st Quartile (25%) 

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

Duewer, Kline, Sharpless, Brown Thomas, Gary, Sowell. Anal Chem 1999;71(9):1870-8.
 

Sample Comments
 

14Ctrl-1 Control Solution 1, nominally 55.0 μm/mL. Displayed Value = (Nominal)(Measured)/(Calculated)
 

14Ctrl-2 Control Solution 2, nominally 27.5 μm/mL. Displayed Value = (Nominal)(Measured)/(Calculated)
 

14Ctrl-3 Control Solution 3, nominally 13.75 μm/mL. Displayed Value = (Nominal)(Measured)/(Calculated)
 

Individualized Report Page 1 / 3 

H4