NISTIR 7880-19 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2003 

Comparability Studies 

Results for Round Robin LIII 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 18 Ascorbic Acid in Human Serum 

David L. Duewer 

Katherine E. Sharpless 

Jeanice B. Thomas 

 

 

 

 

NISTIR 7880-19
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2003 

Comparability Studies 

Results for Round Robin LIII 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 18 Ascorbic Acid in Human Serum 

David L. Duewer 

Katherine E. Sharpless 

Jeanice B. Thomas 

Chemical Sciences Division 

Materials Measurement Laboratory 

-XQH 2013 

U.S. Department of Commerce 

&DPHURQ).HUU\ Acting 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 2003 MMQAP measurement comparability improvement studies: 1) Round Robin LIII FatSoluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 18 Total Ascorbic Acid in 

Human Serum. The materials for both studies were shipped to participants in November 2002; 

participants were requested to provide their measurement results by March 3, 2003. 

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 LIII: Fat-Soluble Vitamins and Carotenoids in Human Serum............................ 1
 

Round Robin 18: Vitamin C in Human Serum............................................................................... 2
 

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

Appendix A. Shipping Package Inserts for RR53........................................................................ A1
 

Appendix B. Final Report for RR53 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR53 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR53 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR18 ......................................................................... E1
 

Appendix F. Final Report for RR18............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR18..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR18............................................... 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 LIII: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

LIII comparability study (hereafter referred to as RR53) received two lyophilized and three 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 

November 2002. 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 RR53 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 all 

analytes reported by at least five participants. 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 18: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 18 comparability study 

(hereafter referred to as RR18) received three 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 

November 2002. 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 RR18 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 RR53 

The following three items were included in each package shipped to an RR53 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
November 13, 2002 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-0001 

Enclosed are the samples for the first fat-soluble vitamins and carotenoids in serum round robin study 

(Round Robin Liii) for the 2003 NIST Micronutrients Measurement Quality Assurance Program. You 

will find one vial of each of three liquid-frozen and two 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 quantification, please 

indicate this result on the form by using NQ (Not Quantified). Results are due to NIST by March 3, 

2003. Results received more than two weeks after the due date will not be included in the summary 

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

Lyophilized samples should be reconstituted with 1.0 mL of HPLC-grade water or equivalent. We 

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

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

possibly interfere with accurate measurement. The rubber stopper contains phthalate esters that may 

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. Water should not be added to the liquid-frozen samples 291-293. 

For consistency, we request that laboratories use the following absorptivities (E 1 % cm): retinal, 1843 at 

325 nm (ethanol); retinyl palmitate, 975 at 325 nm (ethanol); cx-tocopherol, 75.8 at 292 nm (ethanol); ytocopherol, 91.4 at 298 nm (ethanol); ex-carotene, 2800 at 444 nm (hexane); P-carotene, 2560 at 450 nm 

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

Please mail or fax your results for Round Robin Liii to: 

Micronutrients Measurement Quality Assurance Program 

NIST 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 

Fax: (301) 977-0685 

If you have questions or comments regarding this study, please call me at (301) 975-3120; e-mail me at 

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

-0J11trx ~ ~m'lla./J e nice Brown Thomas 

esearch Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

NISI 

A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LIII 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 289 290 291 292 293 Units* 

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 

trans-α-carotene 

total lycopene 

trans-lycopene 

total β-cryptoxanthin 

total α-cryptoxanthin 

total lutein 

total zeaxanthin 

total lutein&zeaxanthin

 total Coenzyme Q10 

ubiquinol (QH2) 

ubiquinone (Qox) 

phylloquinone (K1) 

25-hydroxyvitamin D 

Other analytes? 

* we prefer μg/mL 

Were sera {291,292,293} frozen when received? Yes | No 

Comments: 

Mail: M2QAP 

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

Gaithersburg, MD 20899-8392 3-Mar-2003 Email: David.Duewer@NIST.gov 

A3
 

 

 

 

Participant #: ________ Date: _____________ 

Fat-Soluble Vitamins Round Robin LIII 

NIST Micronutrients Measurement Quality Assurance Program 

Packing List and Shipment Receipt Confirmation Form 

This box contains (we hope) one vial each of the following five FSV M2QAP sera: 

Serum Form Reconstitute? 

#289 Lyophilized Yes (1 ml H2O) 

#290 Lyophilized Yes (1 ml H2O) 

#291 Liquid frozen No 

#292 Liquid frozen No 

#293 Liquid frozen No 

Please 1) Open the pack immediately 

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

3) Check if sera {291,292,293} arrived frozen 

4) Store the samples 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 sera {291,292,293} arrive frozen? Yes | No 

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

6) When do you anticipate analyzing these samples? ________________________ 

Your prompt return of this information is appreciated. 

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 RR53 

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

•	 Cover letter. 

•	 An information sheet that: 

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

o	 describes the content of the “Individualized” report, 

o	 describes the nature of the test samples and details their previous distributions, 

if any, and 

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

participants. 

B1
March 26, 2003 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and .Technology 

Gaithersburg, Maryland 20899-0001 

Enclosed is the summary report of the results for Round Robin Liil (RR 53) 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; 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 NISTassigned 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 53 are provided in the comparability summary (Score 

Card) on page 6 of the "All Lab Report." Laboratory comparability is summarized as follows: results 

rated I to 3 are within 1 to 3 standard deviation(s) of the assigned value, respect~vely; 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. 

Intent-to-participate forms for the 2004 QA program will be mailed in May. This form will provide us 

with formal notification of your intent to participate in the program for the upcoming year. The program 

will consist of two round robin studies for the fat-soluble vitamins and carotenoids and one study for 

vitamin C in serum. To participate in the fat-soluble vitamins and carotenoids in serum studies, the 

participation fee is $1600 for U.S. laboratories and $2000 for non-U.S. laboratories. To participate in the 

vitamin C in serum study, the participation fee is $800 for U.S. laboratories and $1000 for non-U.S. 

laboratories. We ask that you return the form to us by no later than September 1, 2003. 

Samples for the second round robin exercise (RR54) will be distributed during the week of April 7, 

2003. We will send you a reminder via e-mail or fax a week prior to shipment. It is critical that you 

carefully inspect all samples upon arrival and that you promptly confirm to us that they have arrived. 

We will "replace samples (lost or damaged in shipment or miss-packaged by us) only for participants who 

report the problem within one calendar week after the package arrives. 

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. 

ce Brown Thomas 

arch Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Cc: L.C. Sander 

S.A. Wise 

Enclosures NISI 

B2
 

 

The NIST M2QAP Round Robin LIII (RR53) report consists of: 

Page 

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

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

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

n+1 The “target” plot version of your “Comparability Summary” scores. 

Page “All Lab” Report 

1-4 

5a 

5b 

6 

Samples.

Serum 

289 

290 

291 

292 

293 

Results 

“Individualized” Report 

A listing of all results and statistics for analytes reported by at least two laboratories.
 

A list of results for the four analytes reported by only one laboratory. 

A legend for the above two lists.
 

The text version of the “Comparability Summary” (or “Score Card”).
 

 The five sera below were distributed in RR53. 

Description 

Lyophilized, native, single-donor serum 

prepared in 1987. 

Lyophilized, native, single donor, 

commercially obtained serum prepared in 

2002. The same material was used to prepare 

Serum 292. 

Fresh-frozen, native, single-donor serum 

prepared in 2002. 

Fresh-frozen, native, single donor, 

commercially obtained serum prepared in 

2002. The same material was used to prepare 

Serum 290. 

Fresh-frozen, native, single-donor, 

commercially obtained serum prepared in 

2002. This material has rather low levels of 

most micronutrients. 

Prior Distributions 

Serum 93 in RR13 (Jun-88)
 

Serum 111 RR16 (Jun-89)
 

Initial distribution. 

Initial distribution. 

Initial distribution. 

Serum 288 RR52 (Nov-02) 

1)	 Sera Stability. There was no significant change in the median level or in the variability of retinol or 

α-tocopherol in the lyophilized Serum 289 after 15 years; however, the total β-carotene apparently 

has declined by ≈ 0.8% per year but with no significant change in variability. There has been no 

significant change in the median level or variability for any measurand in the fresh-frozen Serum 293 

after six months. 

B3
 

 

2)	 Matrix (Lyophilized Vs Fresh-Frozen) Differences. Sera 290 and 292 were prepared from the same 

serum pool. Since we suggest that you reconstitute our lyophilized samples with 1.0 mL water rather 

than to a total volume of 1.0 mL, the measurand levels in Serum 290 should be ≈ 96% of those in 

Serum 292. The observed average ±SD over all measurands with 10 or more quantitative 

measurements is 95.1 ±0.8%. If any of your Sera 290/292 ratios are much different than 0.95, you 

may want to take a hard look at your measurement system for those measurands. 

For those of you who remember that we’ve been studying the potential interactions between 

measurement systems and the sample matrix – we’re still working on it! We hope to finish the report 

within the year. 

3)	 Didehydroretinol. A recent letter (Erhardt JC, Biesalski HK, Malaba LC, Craft NE. Improved 

Method for Measurement of Retinol and Didehydroretinol in the Modified Relative Dose Response 

Test to Detect Vitamin A Deficiency. Clin Chem 2003 49:338-339) suggested that didehydroretinol 

be used as a marker for Vitamin A deficiency. Participant 164 found measurable levels of this 

measurand in the (obtained more than five years ago) Serum 293. Sad to say, it’s quite plausible that 

the individual who was paid by the commercial vendor for this material may well have been 

nutritionally deficient. 

4)	 Total Retinol and trans-retinol: An Answer to the “Halfway Between” Values for Serum 286 in 

RR52. Thanks to one of our participants who supplied chromatograms and re-evaluated their 

numerical results, we have identified at least one cause for the anomalous “total retinol” values for 

the 13-cis-retinol spiked Serum 286 in the previous Round Robin: quantitation by height in 

combination with modest chromatographic separation between the 13-cis- and trans-retinol isomers. 

Warnings! 

1)	 A few samples in upcoming Round Robins should have measurable didehydroretinol levels. 

2)	 We will soon distribute another pair of sera that have been spiked with trans- and 13-cis-retinol. 

3)	 Whenever you quantitate by peak height, you should be very sure that all isomers you wish to group 

together as the same measurand (i.e, grouping all retinol isomers as “total retinol” and β- and 

γ-tocopherol as “γ/β-tocopherol) elute at exactly the same time. If there is any appreciable peak 

broadening for such a measurand, peak area will be a more appropriate metric than peak height. 

4)	 It is critical that you carefully inspect all samples on arrival and that you promptly confirm to us that 

they have arrived. We will now replace samples (whether lost or damaged in shipment or misspacked by us!) only for participants who report the problem within one calendar week after the 

package’s arrival. 

B4
Appendix C. “All-Lab Report” for RR53 

The following seven 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 analysts. The NIST results are not used in the assessment of the 

consensus summary results of the study. 

C1
Round Robin LIII Laboratory Results 

All Results in μg/mL 

Total Retinol trans-Retinol Retinyl Palmitate α-Tocopherol γ/β-Tocopherol 

Lab 289 290 291 292 293 

C2

FSV-BA 0.821 0.640 0.554 0.663 0.336 

FSV-BB 0.774 0.599 0.497 0.634 0.325 

FSV-BD 0.715 0.660 0.556 0.674 0.368 

FSV-BE ≥0.690 ≥0.570 ≥0.490 ≥0.670 ≥0.330

FSV-BF 0.750 0.620 0.530 0.640 0.310 

FSV-BG 0.791 0.601 0.521 0.590 0.300 

FSV-BH 0.715 0.604 0.509 0.605 0.317 

FSV-BI 0.761 0.593 0.537 0.649 0.328 

FSV-BJ 0.771 0.599 0.506 0.621 0.324 

FSV-BK 0.794 0.600 0.535 0.619 0.325 

FSV-BL 0.690 0.630 0.520 0.690 0.320 

FSV-BM 0.670 0.644 0.571 0.679 0.385 

FSV-BN 0.915 0.602 0.551 0.639 0.332 

FSV-BO ≥0.624 ≥0.647 ≥0.481 ≥0.564 ≥0.281

FSV-BP 0.703 0.574 0.494 0.613 0.343 

FSV-BQ 0.680 0.520 0.470 0.590 0.270 

FSV-BR ≥0.780 ≥0.665 ≥0.597 ≥0.676 ≥0.340

FSV-BS 0.684 0.513 0.397 0.551 0.270 

FSV-BT 0.913 0.563 0.978 0.695 0.445 

FSV-BU - 0.589 0.519 0.620 0.403 

FSV-BV 0.859 0.700 0.591 0.714 0.370 

FSV-BW 0.779 0.609 0.532 0.643 0.335 

FSV-BX ≥0.781 ≥0.597 ≥0.565 ≥0.639 ≥0.331

FSV-CB 0.528 0.522 0.458 0.547 0.281 

FSV-CC 0.820 0.640 0.540 0.690 0.350 

FSV-CD 0.827 0.619 0.536 0.643 0.335 

FSV-CE 0.708 0.557 0.567 0.612 0.297 

FSV-CF 0.840 0.663 0.576 0.680 0.350 

FSV-CG 0.702 0.586 0.517 0.604 0.314 

FSV-CI 0.660 0.620 0.530 0.650 0.340 

FSV-CL 0.707 0.516 0.407 0.548 0.300 

FSV-CR 0.730 0.660 0.600 0.700 0.340 

FSV-CS ≥0.864 ≥0.644 ≥0.573 ≥0.685 ≥0.359

FSV-CT 

FSV-CW ≥0.696 ≥0.513 ≥0.450 ≥0.536 ≥0.316

FSV-CZ 0.780 0.600 0.490 0.600 0.330 

FSV-DA ≥0.789 ≥0.598 ≥0.529 ≥0.639 ≥0.322

FSV-DD ≥0.802 ≥0.620 ≥0.559 ≥0.719 ≥0.315

FSV-DF 0.769 0.654 0.588 0.685 0.366 

FSV-DI 0.885 0.734 0.616 0.730 0.404 

FSV-DW 0.764 0.609 0.502 0.612 0.319 

FSV-ET 0.680 0.590 0.530 0.600 0.300 

289 290 291 292 293 

0.690 0.570 0.490 0.670 0.330 

0.624 0.647 0.481 0.564 0.281 

0.780 0.665 0.597 0.676 0.340 

0.781 0.597 0.565 0.639 0.331 

0.790 0.640 0.540 0.690 0.350 

0.864 0.644 0.573 0.685 0.359 

0.696 0.513 0.450 0.536 0.316 

0.789 0.598 0.529 0.639 0.322 

0.802 0.620 0.559 0.719 0.315 

289 290 291 292 293 

0.020 0.104 0.088 0.105 0.019 

0.017 0.081 0.081 0.084 0.010 

0.034 0.123 0.100 0.090 0.019 

nd 0.103 0.107 0.116 nd 

nq 0.087 0.076 0.087 nq 

nd 0.068 0.060 0.062 nq 

0.102 0.139 0.145 0.149 0.030 

0.013 0.137 0.128 0.152 0.021 

nd 0.108 0.110 0.120 0.019 

0.030 0.100 0.070 0.100 0.020 

<0.010 0.073 0.069 0.077 0.011 

0.011 0.071 

0.012 0.100 

0.065 0.104 0.011 

0.071 0.099 0.016 

289 290 291 292 293 

5.00 10.20 11.23 10.47 2.83 

5.06 10.45 11.67 10.90 2.91 

5.50 11.00 12.20 11.10 3.30 

4.90 9.40 10.70 10.70 2.90 

4.80 10.00 11.30 10.40 2.80 

4.99 9.99 11.71 9.84 2.60 

5.00 10.62 11.48 10.69 2.91 

5.09 10.18 11.55 11.40 3.01 

4.61 10.07 12.52 10.57 2.76 

4.70 9.90 11.30 10.30 2.50 

4.31 11.63 12.92 12.92 3.45 

5.30 10.80 12.00 11.00 3.40 

4.43 8.64 10.44 9.13 2.30 

4.35 9.76 9.56 9.48 2.58 

5.13 10.48 11.09 9.89 2.76 

4.60 9.00 9.90 10.30 2.60 

4.12 10.52 11.40 10.88 2.88 

5.15 11.13 10.70 11.91 3.24 

- 9.04 10.11 9.45 2.55 

4.44 9.60 9.66 10.45 3.58 

5.00 10.20 11.54 10.81 3.00 

4.65 9.75 12.20 10.51 2.92 

4.48 9.05 10.32 9.58 2.67 

5.02 10.50 11.52 10.93 3.15 

4.64 10.52 11.73 11.02 2.62 

4.66 9.56 12.75 10.87 2.73 

5.50 10.50 12.30 11.10 3.40 

4.25 9.18 10.58 9.18 2.37 

5.40 9.30 9.50 10.10 2.90 

4.01 8.59 9.28 8.64 2.70 

4.97 10.91 12.07 11.67 2.91 

5.23 10.07 11.80 10.67 3.02 

4.40 9.00 9.90 9.60 2.50 

4.50 10.00 10.80 9.90 2.90 

4.79 9.67 10.98 10.69 2.84 

5.90 11.30 12.10 11.20 3.46 

4.86 10.34 12.10 10.78 3.27 

4.60 9.50 11.20 9.80 2.50 

289 290 291 292 

2.48 1.85 1.73 1.89 

2.24 1.68 1.52 1.77 

2.40 1.60 1.60 1.90 

2.22 1.69 1.58 1.77 

2.35 1.73 1.60 1.66 

5.33 4.07 3.65 4.15 

2.45 1.80 1.69 2.02 

2.37 1.62 1.65 1.67 

2.06 1.32 1.37 1.43 

2.40 1.81 1.51 1.93 

- 1.98 1.86 2.07 

2.34 1.68 1.46 1.82 

2.66 2.05 1.85 2.11 

2.26 1.70 1.70 1.77 

2.40 1.82 1.69 1.84 

2.06 1.66 1.53 1.70 

2.80 1.80 1.70 1.90 

2.83 2.57 2.09 2.56 

2.40 1.80 1.60 1.90 

2.40 1.76 1.66 1.92 

3.26 2.23 1.97 2.21 

2.40 1.80 1.70 1.80 

N 32 33 33 33 33 9 9 9 9 9 8 13 13 13 10 37 38 38 38 38 21 22 22 22 

Min 0.528 0.513 0.397 0.547 0.270 0.624 0.513 0.450 0.536 0.281 0.011 0.068 0.060 0.062 0.010 4.01 8.59 9.28 8.64 2.30 2.06 1.32 1.37 1.43 

Median 0.763 0.602 0.530 0.639 0.330 0.781 0.620 0.540 0.670 0.330 0.018 0.100 0.081 0.100 0.019 4.80 10.03 11.35 10.62 2.89 2.40 1.80 1.67 1.90 

Max 0.915 0.734 0.978 0.730 0.445 0.864 0.665 0.597 0.719 0.359 0.102 0.139 0.145 0.152 0.030 5.90 11.63 12.92 12.92 3.58 5.33 4.07 3.65 4.15 

SD 0.073 0.038 0.037 0.055 0.027 0.070 0.035 0.056 0.034 0.018 0.013 0.020 0.027 0.022 0.006 0.42 0.73 0.99 0.77 0.28 0.12 0.12 0.10 0.17 

CV 10 6 7 9 8 9 6 10 5 5 73 20 34 22 30 9 7 9 7 10 5 7 6 9 

Npast 28 0 0 0 38 0 0 0 0 5 0 0 0 0 9 26 0 0 0 39 0 0 0 0 

Medianpast 0.752 0.322 0.333 0.015 4.92 2.97 

SDpast 0.041 0.032 0.017 0.006 0.38 0.33 

NISTa 0.766 ≥0.621 ≥0.579 ≥0.689 ≥0.351 0.717 0.621 0.579 0.689 0.351 4.42 10.01 10.90 10.52 2.85 2.17 1.86 1.85 1.90 

NISTb
 0.764 0.636 0.557 0.671 0.348 0.698 0.634 0.557 0.671 0.348 4.99 10.17 10.89 10.67 2.85 2.17 1.60 1.45 1.67 

NNIST 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 

Mean 0.765 0.629 0.568 0.680 0.350 0.707 0.627 0.568 0.680 0.350 4.70 10.09 10.89 10.59 2.86 2.17 1.73 1.65 1.78 

Srep 0.014 0.031 0.018 0.015 0.006 0.012 0.031 0.018 0.015 0.006 0.30 0.31 0.22 0.12 0.07 0.13 0.04 0.06 0.03 

Shet 0.038 0.014 0.004 0.004 0.002 0.050 0.013 0.004 0.004 0.002 0.14 0.42 0.25 0.25 0.05 0.06 0.02 0.05 0.03 

Sanl 0.001 0.011 0.016 0.012 0.002 0.013 0.009 0.016 0.012 0.002 0.40 0.11 0.01 0.11 0.02 0.00 0.18 0.29 0.16 

SNIST 0.041 0.036 0.024 0.020 0.006 0.053 0.035 0.024 0.020 0.006 0.52 0.54 0.34 0.30 0.09 0.14 0.19 0.30 0.17 

NAV 0.764 0.615 0.549 0.660 0.340 0.744 0.624 0.554 0.675 0.340 0.100 0.081 0.100 0.019 4.75 10.06 11.12 10.61 2.87 2.28 1.77 1.66 1.84 

NAU 0.073 0.051 0.050 0.062 0.031 0.087 0.050 0.059 0.053 0.031 0.026 0.027 0.026 0.011 0.53 0.78 1.05 0.82 0.40 0.29 0.20 0.30 0.22 

All Lab Report 
Round Robin LIII Laboratory Results
 

All Results in μg/mL
 

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

C3

Lab 289 290 291 292 293 289 290 291 292 293 289 290 291 292 293 289 290 291 292 293 28

FSV-BA 0.302 0.115 0.299 0.122 0.048 0.284 0.111 0.284 0.117 0.046 0.018 0.005 0.015 0.006 0.002 0.017 0.071 0.125 0.075 0.005 

FSV-BB 0.299 0.110 0.266 0.116 0.049 0.280 0.105 0.254 0.111 0.046 0.020 0.005 0.012 0.005 0.003 0.015 0.069 0.114 0.071 0.004 

FSV-BD 

FSV-BE 0.280 0.100 0.260 0.120 0.040 

FSV-BF 0.410 0.098 0.294 0.115 0.049 0.021 0.089 0.150 0.091 0.013 

FSV-BG 0.327 0.123 0.318 0.139 0.054 0.025 0.081 0.122 0.088 0.011 

FSV-BH 0.291 0.106 0.283 0.107 0.043 0.271 0.106 0.270 0.107 0.043 0.020 nq 0.013 nq nq nq 0.068 0.116 0.068 nq
 

FSV-BI
 0.326 0.118 0.301 0.128 0.053 0.019 0.068 0.118 0.072 0.004
 

FSV-BJ
 0.256 0.109 0.303 0.116 0.044 nq 0.099 0.171 0.102 nq 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.308 0.091 0.258 0.089 0.043 0.277 0.086 0.243 0.086 0.034 0.023 nd 0.005 nq nq 0.012 0.060 0.116 0.060 nq 

FSV-BO 0.295 0.110 0.260 0.105 0.048 0.015 0.062 0.100 0.058 nq 

FSV-BP 0.286 0.114 0.219 0.135 0.073 0.007 0.042 0.075 0.047 0.005 

FSV-BQ 

FSV-BR 

FSV-BS ≥0.415 ≥0.126 ≥0.317 ≥0.128 ≥0.034 0.415 0.126 0.317 0.128 0.034 nq ≥0.071 ≥0.112 ≥0.062 nq n

FSV-BT
 0.321 0.119 0.294 0.137 0.061 0.297 0.112 0.275 0.129 0.058 0.024 0.007 0.018 0.008 0.003 0.018 0.073 0.113 0.084 0.010 

FSV-BU 0.351 0.133 0.340 0.147 0.064 0.019 0.083 0.150 0.089 0.006 

FSV-BV 0.310 0.121 0.256 0.132 0.057 0.012 0.068 0.093 0.073 0.004 

FSV-BW 0.302 0.114 0.285 0.121 0.050 0.012 0.091 0.159 0.095 nq 

FSV-BX ≥0.288 ≥0.115 ≥0.305 ≥0.123 ≥0.050 0.288 0.115 0.305 0.123 0.050 0.017 0.083 0.143 0.089 0.009 

FSV-CB 0.287 0.092 0.268 0.098 0.051 0.013 0.053 0.099 0.057 0.004 

FSV-CC 

FSV-CD 0.300 0.117 0.271 0.117 0.041 0.017 0.071 0.112 0.079 nd 

FSV-CE 0.301 0.106 0.345 0.111 0.044 

FSV-CF 

FSV-CG 0.279 0.109 0.273 0.116 0.048 0.253 0.101 0.254 0.108 0.044 0.026 0.007 0.019 0.007 0.004 0.015 0.066 0.112 0.070 0.004
 

FSV-CI
 ≥0.286 ≥0.095 ≥0.223 ≥0.099 ≥0.039 0.29 0.10 0.22 0.10 0.04 0.017 0.066 0.081 0.068 <0.009 

FSV-CL 0.261 0.108 0.208 0.097 0.048 0.015 0.067 0.091 0.062 0.005 

FSV-CR 

FSV-CS 0.357 0.154 0.394 0.170 0.068 0.302 0.116 0.248 0.119 0.051 0.03 0.01 0.02 0.01 0.00 0.019 0.080 0.121 0.084 0.005 

FSV-CT 0.330 0.100 0.260 0.090 0.053 

FSV-CW 0.312 0.113 0.282 0.119 0.052 0.288 0.106 0.263 0.111 0.049 0.024 0.007 0.019 0.008 0.003 0.021 0.070 0.120 0.074 0.007 0.0

FSV-CZ 0.260 0.170 0.340 0.170 0.050 

FSV-DA 0.323 0.127 0.294 0.143 0.068 0.295 0.110 0.270 0.129 0.057 0.028 0.017 0.024 0.014 0.012 0.020 0.076 0.123 0.087 0.016 

FSV-DD 

FSV-DF 

FSV-DI ≥0.403 ≥0.132 ≥0.293 ≥0.130 ≥0.059 0.403 0.132 0.293 0.130 0.059 

FSV-DW 0.386 0.140 0.327 0.140 0.060 0.332 0.121 0.288 0.122 0.051 0.054 0.019 0.039 0.018 0.010 

FSV-ET 0.310 0.110 0.260 0.110 0.040 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NISTa 

NISTb 

NNIST 

Mean 

Srep 

Shet 

Sanl 

SNIST 

27 27 

0.256 0.091 

0.302 0.113 

0.410 0.170 

0.026	 0.010 

9 9 

18 0 

0.343 

0.035 

4 4 

0.332 0.112 

0.011 0.003 

0.009 0.002 

0.008 0.005 

0.016 0.006 

27 

0.208 

0.283 

0.394 

0.031 

11 

0 

4 

0.274 

0.007 

0.006 

0.003 

0.010 

27 

0.089 

0.119 

0.170 

0.019 

16 

0 

4 

0.115 

0.003 

0.001 

0.002 

0.004 

27 

0.040 

0.050 

0.073 

0.007 

14 

28 

0.049 

0.008 

4 

0.050 

0.001 

0.000 

0.004 

0.005 

14 

0.253 

0.288 

0.415 

0.015 

5 

7 

0.330 

0.024 

4 

0.292 

0.020 

0.005 

0.006 

0.021 

14 

0.086 

0.110 

0.132 

0.008 

7 

0 

4 

0.112 

0.003 

0.002 

0.005 

0.006 

14 

0.223 

0.270 

0.317 

0.025 

9 

0 

4 

0.248 

0.005 

0.004 

0.015 

0.017 

14 

0.086 

0.118 

0.130 

0.013 

11 

0 

4 

0.115 

0.003 

0.001 

0.001 

0.003 

14 

0.034 

0.048 

0.059 

0.006 

12 

12 

0.049 

0.006 

4 

0.050 

0.001 

0.000 

0.004 

0.005 

10 

0.018 

0.024 

0.054 

0.005 

21 

0 

4 

0.040 

0.013 

0.011 

0.013 

0.022 

8 

0.005 

0.007 

0.019 

0.003 

44 

0 

10 

0.005 

0.019 

0.039 

0.005 

26 

0 

4 

0.025 

0.005 

0.003 

0.013 

0.014 

8 

0.005 

0.008 

0.018 

0.002 

29 

0 

1 

0.002 

8 

0.002 

0.003 

0.012 

0.002 

58 

6 

0.003 

0.001 

1 

21 

0.007 

0.017 

0.025 

0.003 

19 

0 

2 

0.016 

0.002 

0.002 

0.003 

23 

0.042 

0.070 

0.099 

0.011 

15 

0 

4 

0.080 

0.003 

0.006 

0.004 

0.008 

23 

0.075 

0.116 

0.171 

0.013 

11 

0 

4 

0.106 

0.002 

0.004 

0.011 

0.012 

23 

0.047 

0.074 

0.102 

0.014 

20 

0 

4 

0.079 

0.003 

0.004 

0.002 

0.006 

16 

0.004 

0.005 

0.016 

0.003 

68 

18 

0.005 

0.004 

2 

0.004 

0.001 

0.001 

0.001 

0.0

0.0

0.0

0.0

0.0

0.337 ≥0.115 0.272 ≥0.113 ≥0.053

0.326 ≥0.108 0.276 0.118 ≥0.047

0.288 0.115 0.238 0.113 0.053 

0.296 0.108 0.259 0.116 0.047 

0.049 nd 0.034 nd nd 

0.030 nd 0.017 0.002 nd 

nd 0.083 0.099 0.077 nd 

0.018 0.083 ≥0.114 0.086 ≥0.004 0.0

NAV 

NAU 

0.317 0.112 0.278 0.117 0.050 0.290 0.111 0.259 0.116 0.049 0.032 0.022 0.005 0.017 0.075 0.111 0.076 0.004 

0.049 0.019 0.042 0.020 0.011 0.031 0.014 0.033 0.015 0.009 0.025 0.015 0.006 0.006 0.022 0.033 0.022 0.004 

All Lab Report	 
Round Robin LIII Laboratory Results
 

All Results in μg/mL
 

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

C4

Lab 289 290 291 292 293 289 290 291 292 293 289 290 291 292 293 289 290 291 292 293 289 290 291 292 

FSV-BA 0.164 0.302 0.240 0.316 0.107 0.032 0.065 0.067 0.068 0.023 

FSV-BB 0.268 0.449 0.368 0.473 0.189 0.127 0.237 0.180 0.251 0.087 0.026 0.052 0.052 0.055 0.018 0.010 0.022 0.042 0.024 0.010 0.041 0.078 0.188 0.0

FSV-BD 

FSV-BE 

FSV-BF 0.339 0.506 0.437 0.532 0.209 0.027 0.049 0.047 0.051 0.017 

FSV-BG 0.256 0.549 0.438 0.601 0.200 0.154 0.321 0.240 0.345 0.107 0.019 0.047 0.049 0.056 0.014 0.052 0.073 0.172 0.0

FSV-BH 0.266 0.489 0.406 0.495 0.179 0.028 0.064 0.060 0.065 0.020 0.031 0.052 0.138 0.0

FSV-BI
 0.218 0.388 0.315 0.418 0.156 0.028 0.058 0.060 0.063 0.020 0.041 0.090 0.211 0.1

FSV-BJ
 0.266 0.564 0.461 0.586 0.202 0.024 0.049 0.045 0.053 0.014 0.034 0.081 0.183 0.0

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.246 0.373 0.343 0.374 0.148 0.128 0.212 0.170 0.213 0.076 0.012 0.033 0.029 0.030 nq nd 0.005 0.024 nq nq 0.029 0.046 0.123 0.0

FSV-BO 0.281 0.506 0.392 0.472 0.193 0.023 0.050 0.048 0.049 0.016 0.023 0.043 0.113 0.0

FSV-BP 0.244 0.508 0.324 0.518 0.203 0.028 0.051 0.093 0.042 0.042 

FSV-BQ 

FSV-BR 

FSV-BS 0.393 0.621 0.487 0.659 0.234 

FSV-BT 0.299 0.477 0.421 0.550 0.221 0.114 0.185 0.159 0.212 0.085 0.029 0.056 0.062 0.063 0.023 0.035 0.055 0.214 0.0

FSV-BU 0.314 0.561 0.456 0.606 0.227 0.026 0.047 0.041 0.050 0.015 

FSV-BV 0.302 0.581 0.399 0.628 0.214 0.021 0.048 0.036 0.051 0.015 

FSV-BW 0.255 0.474 0.367 0.509 0.179 

FSV-BX 0.122 0.206 0.182 0.228 0.080 0.024 0.043 0.045 0.048 0.018 0.039 0.077 0.206 0.0

FSV-CB 0.226 0.338 0.349 0.345 0.165 0.025 0.056 0.050 0.061 0.021 0.065 0.0

FSV-CC 

FSV-CD 0.291 0.379 0.347 0.409 0.135 0.024 0.044 0.036 0.047 0.017 

FSV-CE 

FSV-CF 

FSV-CG 0.250 0.441 0.375 0.475 0.167 0.129 0.245 0.190 0.266 0.086 0.028 0.049 0.055 0.056 0.020
 

FSV-CI
 0.039 0.065 0.137 0.0

FSV-CL 0.268 0.501 0.348 0.477 0.195 0.027 0.062 0.058 0.061 0.020 0.008 0.033 0.058 0.033 0.010 

FSV-CR 

FSV-CS 0.293 0.547 0.394 0.546 0.219 0.028 0.050 0.048 0.051 0.018 0.046 0.078 0.139 0.0

FSV-CT 0.330 0.580 0.440 0.540 0.230 0.027 0.052 0.055 0.046 0.016 0.047 0.076 0.206 0.0

FSV-CW 0.289 0.468 0.408 0.489 0.203 0.131 0.222 0.172 0.236 0.088 0.033 0.055 0.058 0.057 0.022 ≥0.031 ≥0.058 ≥0.141 ≥0.06

FSV-CZ 

FSV-DA 0.288 0.464 0.387 0.556 0.204 0.153 0.257 0.203 0.311 0.107 0.036 0.050 0.056 0.066 0.021 0.013 0.021 0.041 0.027 0.011 ≥0.032 ≥0.055 ≥0.147 ≥0.06

FSV-DD 

FSV-DF 

FSV-DI 0.253 0.429 0.267 0.421 0.158 0.045 0.118 0.240 0.1

FSV-DW 0.136 0.243 0.188 0.248 0.032 0.040 0.077 0.078 0.080 0.024 0.044 0.083 0.185 0.0

FSV-ET 

N 22 22 22 22 22 11 11 11 11 11 23 23 23 23 22 3 4 4 3 3 14 15 14 

Min 0.218 0.338 0.315 0.345 0.135 0.114 0.185 0.159 0.212 0.032 0.012 0.033 0.029 0.030 0.014 0.008 0.005 0.024 0.024 0.010 0.023 0.043 0.113 0.04

Median 0.275 0.495 0.393 0.514 0.201 0.131 0.243 0.188 0.251 0.087 0.027 0.050 0.052 0.055 0.019 0.010 0.021 0.041 0.027 0.010 0.040 0.076 0.184 0.0

Max 0.393 0.621 0.487 0.659 0.234 0.253 0.429 0.267 0.421 0.158 0.040 0.077 0.093 0.080 0.042 0.013 0.033 0.058 0.033 0.011 0.052 0.118 0.240 0.1

SD 0.031 0.071 0.059 0.060 0.025 0.019 0.047 0.034 0.061 0.018 0.003 0.006 0.010 0.009 0.004 0.008 0.015 0.050 0.0

CV 11 14 15 12 12 15 19 18 24 21 12 11 19 17 19 19 19 27 

Npast 0 0 0 0 21 0 0 0 0 11 0 0 0 0 23 0 0 0 0 0 0 0 0 

Medianpast 0.181 0.096 0.019 

SDpast 0.027 0.012 0.003 

NISTa 

NISTb 0.314 0.548 0.414 0.574 0.212 

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

0.038 0.071 0.076 0.076 nd 0.045 0.102 0.231 0.1

0.028 0.060 0.049 0.062 0.020 0.016 0.032 0.053 0.034 0.015 ≥0.038 ≥0.080 ≥0.174 ≥0.07

Mean 0.314 0.548 0.414 0.574 0.213 0.033 0.066 0.062 0.069 0.021 0.016 0.032 0.053 0.034 0.015 0.045 0.102 0.231 0.1

Srep 0.015 0.003 0.012 0.009 0.010 0.003 0.004 0.002 0.005 0.001 0.000 0.001 0.004 0.002 0.002 0.009 0.017 0.009 0.0

Shet 0.012 0.001 0.010 0.011 0.002 0.005 0.001 0.002 0.002 0.002 0.000 0.001 0.001 0.001 0.000 0.002 0.009 0.001 0.0

Sanl 0.007 0.008 0.019 0.010 

SNIST 0.019 0.003 0.016 0.014 0.010 0.009 0.009 0.019 0.011 0.002 0.000 0.001 0.004 0.002 0.002 0.010 0.019 0.009 0.0

NAV 0.295 0.521 0.403 0.544 0.207 0.131 0.243 0.188 0.251 0.087 0.030 0.058 0.057 0.062 0.020 

0.069 0.109 0.086 0.114 0.050 0.023 0.047 0.034 0.061 0.018 0.010 0.016 0.020 0.017 0.005 

0.042 0.089 0.208 0.0

NAU
 0.010 0.027 0.060 0.0

All Lab Report 
Round Robin LIII Laboratory Results 

All Results in μg/mL 

Total Zeaxanthin Total Lutein&Zeaxanthin Coenzyme Q10 Phylloquinone (K1) 

C5

Lab 289 290 291 292 293 289 290 291 292 586 289 290 291 292 293 289 290 291 292 293 28

FSV-BA 0.053 0.109 0.227 0.112 0.067 

FSV-BB 0.023 0.050 0.046 0.050 0.027 0.064 0.128 0.303 0.130 0.073 

FSV-BD 

FSV-BE 0.23 0.29 0.49 0.17 0.21 

FSV-BF 0.051 0.110 0.202 0.115 0.055 

FSV-BG 0.012 0.019 0.047 0.028 0.015 0.059 0.083 0.203 0.096 0.045 

FSV-BH 0.008 0.028 0.037 0.030 0.018 0.039 0.080 0.175 0.085 0.052
 

FSV-BI
 0.013 0.033 0.038 0.037 0.019 0.054 0.123 0.303 0.142 0.073 

FSV-BJ
 

FSV-BK
 

FSV-BL
 

FSV-BM
 

FSV-BN
 0.033 0.055 0.135 0.058 0.036 

FSV-BO 0.009 0.030 0.039 0.026 0.014 0.0316 0.0722 0.1519 0.0688 0.0387 

FSV-BP 0.095 0.108 0.210 0.119 0.089 

FSV-BQ 

FSV-BR 

FSV-BS 0.060 0.200 0.401 0.206 0.086 

FSV-BT 0.013 0.034 0.070 0.037 0.018 0.048 0.088 0.285 0.105 0.068 

FSV-BU 0.065 0.141 0.340 0.150 0.071 

FSV-BV 0.050 0.120 0.231 0.125 0.065 

FSV-BW 0.470 0.640 0.560 0.700 0.410 

FSV-BX 0.008 0.024 0.030 0.026 0.016 0.048 0.101 0.236 0.109 0.061 

FSV-CB 0.033 0.030 0.029 0.057 0.098 0.260 0.094 0.060 

FSV-CC 

FSV-CD 0.047 0.104 0.200 0.106 0.051 

FSV-CE 

FSV-CF 

FSV-CG 0.053 0.128 0.249 0.137 0.069
 

FSV-CI
 0.015 0.029 0.031 0.031 0.016 0.054 0.094 0.168 0.099 0.057 0.36 0.33 0.72 0.19 0.16 

FSV-CL 0.045 0.101 0.189 0.012 0.055 0.0

FSV-CR 

FSV-CS 0.012 0.024 0.021 0.023 0.013 0.058 0.101 0.161 0.101 0.055 

FSV-CT nq 0.025 0.038 0.020 0.014 0.047 0.100 0.244 0.101 0.065 

FSV-CW 0.015 0.033 0.056 0.035 0.019 ≥0.046 ≥0.091 ≥0.197 ≥0.097 ≥0.056 0.700 1.000 0.900 1.100 0.500 

FSV-CZ 0.570 0.920 0.580 0.960 0.660 

FSV-DA ≥0.014 ≥0.030 ≥0.036 ≥0.030 ≥0.018 0.065 0.111 0.214 0.122 0.068 0.0

FSV-DD 

FSV-DF 

FSV-DI 0.293 0.397 0.262 0.401 0.254 0.33 0.29 0.67 0.31 0.18 

FSV-DW 0.038 0.082 0.097 0.088 0.043 0.082 0.165 0.282 0.180 0.093 

FSV-ET 

NISTa 

NISTb 

NNIST 

0.019 0.044 0.051 0.041 0.023 ≥0.057 ≥0.124 ≥0.224 ≥0.120 ≥0.064

2 2 2 2 2 2 2 2 2 2 

N 11 13 12 13 13 23 23 23 23 23 4 4 4 4 4 3 3 3 3 3 

Min 0.008 0.019 0.021 0.020 0.013 0.032 0.055 0.135 0.012 0.036 0.293 0.397 0.262 0.401 0.254 0.23 0.29 0.49 0.17 0.16 0.0

Median 0.013 0.030 0.038 0.030 0.018 0.053 0.104 0.227 0.109 0.065 0.520 0.780 0.570 0.830 0.455 0.33 0.29 0.67 0.19 0.18 0.0

Max 0.038 0.082 0.097 0.088 0.043 0.095 0.200 0.401 0.206 0.093 0.700 1.000 0.900 1.100 0.660 0.36 0.33 0.72 0.31 0.21 0.0

SD 0.003 0.006 0.010 0.008 0.003 0.009 0.019 0.057 0.022 0.011 

CV 26 20 27 27 16 17 18 25 20 17 

Npast 0 0 0 0 14 0 0 0 0 20 0 0 0 0 0 0 0 0 0 0 

Medianpast 0.020 0.064 

SDpast 0.003 0.016 

Mean 0.019 0.044 0.051 0.041 0.023 0.057 0.124 0.224 0.120 0.048
 

Srep 0.001 0.001 0.003 0.002 0.004 0.002 0.004 0.005 0.006 0.033
 

Shet 0.000 0.004 0.003 0.001 0.002 0.003 0.005 0.001 0.002 0.022
 

Sanl
 

SNIST 0.001 0.004 0.004 0.003 0.004 0.004 0.007 0.005 0.006 0.039 

NAV 

NAU 

0.016 0.037 0.044 0.036 0.020 0.055 0.114 0.226 0.114 0.057 

0.006 0.013 0.014 0.012 0.007 0.012 0.026 0.057 0.024 0.041 

All Lab Report 
 

 

 

 

 

Round Robin LIII Laboratory Results
 

All Results in μg/mL
 

Analytes Reported By One Laboratory 

Term 

N 

Min 

Medianpart 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NNIST 

MeanNIST 

Srep 

Shet 

Sanl 

SNIST 

NAV 

NAU 

-

nd 

nq 

≥x

italics

Analyte Code 289 290 291 292 293 

trans-Zeaxanthin FSV-DA 0.014 0.030 0.036 0.030 0.054 

Didehydroretinol FSV-DF nd nd nd nd 0.090 

Ubiquinol FSV-BW 0.310 0.440 0.350 0.420 0.320 

Ubiquinone FSV-BW 0.160 0.200 0.210 0.280 0.105 

Phytoene FSV-CL nd 0.120 0.070 0.103 0.018 

Retinyl stearate FSV-DA 0.010 0.030 0.050 0.030 0.018 

Legend 

Definition

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

 Minimum (non-NIST) quantitative value reported

 Median (non-NIST) quantitative value reported 

 Maximum (non-NIST) quantitative value reported

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

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

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

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

 Pooled SD from past RR(s)
 

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

 Mean of the NIST-analyzed vial means

 W ithin-vial pooled standard deviation

 Among-vial pooled standard deviation

 Between NIST analyst standard deviation 

2

)

0.5 Total standard deviation for NIST analyses: (Srep 2

 + Shet 2 + Sanl 

 NIST Assigned Value

 = (Medianpart + MeanNIST)/2 for analytes reported by NIST analyst(s)

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

2

)

0.5 NIST Assigned Uncertainty: (S2

 + Sbtw 

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

 deviation between Medianpart and MeanNIST. The expected long-term SD, eSD,

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

 Not analyzed

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

 Detected but not quantitatively determined

 Concentration greater than or equal to x

 Not explictly reported but calculated by NIST from reported values

All Lab Report Page 5 / 6 

C6
 

 

 

 

 

 

Round Robin LIII Laboratory Results 

Comparability Summary 

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-CI 

FSV-CL 

TR aT g/bT bC tbC aC TLy tLy TbX TLu TZ
 

1 1 1 1 1 1 2 1 1 1
 

1 1 1 1 1 1 1 1 1 1 1
 

1 2
 

1 1 1 1
 

1 1 1 2 2 1
 

1 1 1 1 2 1 2 1
 

1 1 4 1 1 1 1 1 1 2
 

1 1 1 1 1 1 1 1 1
 

1 1 1 1 2 1 1 1 1
 

1 1
 

1 2 1 1
 

2 1
 

2 2 2 1 2 1 1 1 1
 

2 1 1 1 1 1 2
 

1 1 2 2 1 3
 

2 1 2 2
 

1
 

2 3 2 1 1 1
 

4 2 1 1 1 1 1 1 1 2 1
 

2 2 1 2 1 1 1 1 2
 

2 2 1 1 1 1
 

1 1 2 1 2 1
 

1 1 1 1 1 1
 

3 1 1 1 2
 

1 1
 

1 1 1 1 1 1 1
 

1 1 1 1
 

1 2 1
 

1 2 1 1 1 1 1 1 1
 

1 2 1 2 1
 

2 2 3 2 1 1
 

FSV-CR 2 1
 

FSV-CS 1 3 1 1 1 1 1 1
 

FSV-CT 1 1 1 1
 

FSV-CW 2 1 1 1 1 1 1
 

FSV-CZ 1 1 3
 

Label

Lab 

TR

aT 

g/bT

bC 

tbC 

aC 

TLy

tLy 

TbX 

TLu 

TZ

TL&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 

 trans-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
 

NAU i
 

CS = 



 





 

2
 2 + C + AP

N 

i 1
 

AP = Apparent Precision = 

C = Concordance = 

FSV-DA 1 1 2 1 2 1 1 2 1 4
 Nyou 

FSV-DF 1 2
 2
 you

∑ 

= 

N
 

i 1
 

















i
 

NISTa 1 1 1 1 1 2 1
 NAU = NIST Assigned Uncertainty 

NISTb 1 1 1 1 1 1 1 1 1
 

n 34 40 24 29 16 25 23 11 25 16 14 For further details, please see
 

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

KT. Micronutrients Measurement Quality Assurance TR aT g/bT bC tbC aC TLy tLy TbX TLu TZ 

Program: Helping participants use interlaboratory comparison % 1
 68 68 79 72 75 76 91 64 84 81 71
 exercise results to improve their long-term measurement % 2
 24 33 8 21 13 24 9 27 12 19 21
 performance. Anal Chem 1999;71(9):1870-8. % 3
 6 0 8 7 13 0 0 0 4 0 0
 

% 4
 3 0 4 0 0 0 0 9 0 0 7 

Youi
 

N
 

−Median
 

NAU i
 

1
 

FSV-DI 3 2 3 3 4 1 1
 

FSV-DW 1 1 2 1 2
 

FSV-ET 1 1 1 1
 you −

All Lab Report Page 6 / 6
 

C7
 

Appendix D. Representative “Individualized Report” for RR53 

Each participant in RR53 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 RR53: 

• 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 Lutein 

• Total Zeaxanthin 

• Total Lutein & Zeaxanthin 

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

participant FSV-BA. 

D1
 

 Set 1 of 42 

Individualized Round Robin LIII Report: FSV-BA 

Summary 

Serum 289 Serum 290 Serum 291 Serum 292 

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

Total Retinol 0.821 0.764 32 0.640 0.615 33 0.554 0.549 33 0.663 0.660 3

Retinyl Palmitate 0.02 8 0.1 0.1 13 0.1 0.1 13 0.10 0.10 1

α-Tocopherol 5.00 4.75 37 10.20 10.06 38 11.23 11.12 38 10.47 10.61 3

γ/β-Tocopherol 2.478 2.284 21 1.853 1.767 22 1.732 1.662 22 1.894 1.839 2

Total β-Carotene 0.302 0.317 27 0.115 0.112 27 0.299 0.278 27 0.122 0.117 2

trans-β-Carotene 0.284 0.290 14 0.111 0.111 14 0.284 0.259 14 0.117 0.116 1

Total cis-β-Carotene 0.018 0.032 10 0.005 8 0.015 0.022 10 0.006 0.005 

Total α-Carotene 0.017 0.017 21 0.071 0.075 23 0.125 0.111 23 0.075 0.076 2

trans-Lycopene 0.164 0.131 11 0.302 0.243 11 0.240 0.188 11 0.316 0.251 1

Total β-Cryptoxanthin 0.032 0.030 23 0.065 0.058 23 0.067 0.057 23 0.068 0.062 2

Total Lutein&Zeaxanthin 0.053 0.055 23 0.109 0.114 23 0.227 0.226 23 0.112 0.114 2

D2

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

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

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

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

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 USA Email

Individualized Report 
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

Total Retinol 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 2 / 12 

D3
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

Retinyl Palmitate 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 3 / 12 

D4
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

α-Tocopherol 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 4 / 12 

D5
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

γ/β-Tocopherol 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 5 / 12 

D6
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

Total β-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 6 / 12 

D7
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

trans-β-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 7 / 12 

D8
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

Total α-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 8 / 12 

D9
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

trans-Lycopene 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 9 / 12 

D10
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

Total β-Cryptoxanthin 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 10 / 12 

D11
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.

 

 Set 1 of 42 

Individualized RR LIII Report: FSV-BA 

Total Lutein&Zeaxanthin 

Apparent Precision, SD 

[Analyte], μg/mL 

93

111289291288293290292 

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) 

You, this RR You, ≥x, this RR NIST, this RR 

Median (50%) 

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

Serum History Comments 

#289 Lyophilized: #93 RR13 (Jun-88), #111 RR16 (Jun-89) Native, single-source 

#290 Lyophilized: new Native, single-source 

#291 Fresh-frozen: new Native, single-source 

#292 Fresh-frozen: new Same pool as #290 

#293 Fresh-frozen: #288 RR52 Native, single-source 

Individualized Report Page 11 / 12 

D12
Set 1 of 42 

Individualized Round Robin LIII Report: FSV-BA
 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total β-Carotene Tot

D13

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

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

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

Individualized Report 
 

 

Appendix E. Shipping Package Inserts for RR18 

The following five items were included in each package shipped to an RR18 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 

•	 Packing List and Shipment Receipt Confirmation Form 

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. 

E1
November 13, 2002 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-0001 

Enclosed are samples for the vitamin C round robin study (RR 18) for the 2003 NIST 

Micronutrients Measurement Quality Assurance Program. RR 18 consists of three vials 

of frozen serum (test samples) and one vial of solid ascorbic acid (control sample). 

Please follow the attached protocol when you prepare and analyze these samples. If you 

cannot prepare the control sample solutions gravimetrically, please prepare equivalent 

solutions volumetrically and report the exact volumes used. 

Please be reminded that sample contact with any oxidant-contaminated surface (sample 

vials, glassware, etc.) may degrade your measurement system's performance (SA 

Margolis and E Park, "Stability of Ascorbic Acid in Solutions in Autosampler Vials," 

Clinical Chemistry 2001, 47(8), 1463-1464). You should suspect such degradation if you 

observe unusually large variation in replicate analyses, particularly of your calibration 

solutions and/or control samples. 

We recommend that you obtain Standard Reference Material (SRM) 970 Ascorbic 

Acid in Serum to validate your methodology and value assign in-house control 

materials. This SRM may be purchased from the Standard Reference Materials Program 

at NIST. (Tel: 301-975-6776, Fax: 301-948-3730, or e-mail: snninfo@nist.gov) 

Please return your results for RR 18 using the attached form by March 3, 2003 to: 

Micronutrients Measurement Quality Assurance Program 

NIST 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 

Fax: 301-977-0685 

If you have questions or concerns about this study, please contact me at 301-975-3120; email: jbthomas@nist.gov; or mail/fax queries to the above address. 

ice Brown Thomas 

search Chemist 

alytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

E2
 

 

 

 

 

Micronutrient Measurement Quality Assurance Program for
 

Vitamin C
 

Please Read Through Completely BEFORE Analyzing Samples 

Protocol for Preparation and Analysis of the Control Sample 

The control sample consists of a sample of solid ascorbic acid in an amber vial. It should be 

prepared and used in the following manner: 

1.	 Prepare at least 500 mL of 5% mass fraction metaphosphoric acid (MPA) in distilled water. This 

solution will be referred to as the “Diluent” below. 

2.	 Weigh 0.18 to 0.22 g of the solid ascorbic acid sample to 0.0001 g (if possible), dissolve it in the 

Diluent in a 100 mL volumetric flask, and dilute with the Diluent to the 100 mL mark. Weigh 

the amount of Diluent added to 0.1 g. Record the weights. The resulting material will be 

referred to as the “Stock Solution” below. 

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

Dilute Solution 1: Weigh 0.500 mL of the Stock Solution to 0.0001 g into a 100 mL volumetric 

flask; dilute with Diluent to the 100 mL mark. Record the weight. 

Dilute Solution 2: Weigh 0.250 mL of the Stock Solution to 0.0001 g into a 100 mL volumetric 

flask; dilute with Diluent to the 100 mL mark. Record the weight. 

Dilute Solution 3: Weigh 0.125 mL of the Stock Solution to 0.0001 g into a 100 mL volumetric 

flask; dilute with Diluent to the 100 mL mark. Record the weight. 

4.	 Calculate and record the total ascorbic acid concentrations, [TAA], in these Dilute Solutions. 

If you follow the above gravimetric preparation directions, the [TAA] in μmol/L is calculated: 

(g Stock Solution in Dilute Solution 	 ) (⋅ g AA in Stock Solution )⋅(56785 mol/g μ ⋅ L) [TAA] DS = (g AA in Stock Solution ) + (g Diluent in Stock Solution)

For example, if you prepared the Stock Solution with 0.2000 g of solid ascorbic acid and 103.0 g 

of Diluent, then 0.5 mL of the Stock Solution should weigh (0.2+103)/200 = 0.52 g and 

[TAA] DS1 = (0.52 g)(0.2 g)∙(56785 μmol/g·L)/(0.2 + 103 g) = 57.2 μmol/L. Likewise, 0.25 mL 

of the Stock Solution should weigh 0.26 g and [TAA] DS2 = 28.4 μmol/L and 0.125 mL should 

weigh 0.13 g and [TAA] DS3 = 14.2 μmol/L. 

5.	 Measure the ultraviolet absorbance spectrum of Dilute Solution 1 against the Diluent as the blank 

using paired 1 cm path length cuvettes. Record the absorbance of the sample at 242, 243, 244, 

and 245 nm. Record the maximum absorbance (Amax ) within this region. Record the wavelength 

(λmax ) at which this maximum occurs. 

E3
 

 

 

 

 

The extinction coefficient (E1%) of ascorbic acid at λmax (using a cell with a 1 cm path length) of 

Dilute Solution #1 can be calculated: 

dL (A )⋅((g AA in Stock Solution )	 + (g Diluent in Stock Solution )) 1% max E ( ) = g ⋅ cm (g Stock Solution in Dilute Solution 1)⋅(g AA in Stock Solution)

If your spectrophotometer is properly calibrated, λmax should be between 243 and 244 nm and 

E1% should be 550 ± 30 dL/g·cm. If they are not, you should calibrate the wavelength and/or 

absorbance axes of your spectrophotometer and repeat the measurements. 

6.	 Measure and record the concentration of total ascorbic acid in all three dilute solutions and in the 

5% MPA Diluent in duplicate using exactly the same method used for the test samples, including 

any enzymatic treatment. Compare the replicate values. Are you satisfied that your 

measurement precision is adequate? Do not evaluate the test samples until you are satisfied that 

your system is performing properly! 

7.	 Compare the measured with the calculated [TAA] DS values. This is most conveniently done by 

plotting the measured values on the y-axis of a scatterplot against the calculated values on the 

x-axis. The line through the four {calculated, measured} data pairs should go through the origin 

with a slope of 1.0. Are you satisfied with the agreement between the measured and calculated 

values? Do not evaluate the test samples until you are satisfied that your system is performing 

properly! 

Protocol for Analysis of the Test Samples 

The test samples are in sealed ampoules. They 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 ascorbic acid 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 contains between 0.0 and 80.0 μmol of total ascorbic acid/L of solution. The total 

ascorbic acid in each ampoule should be measured in duplicate. Please report your results in 

μmol/(L of the sample solution) rather than μmol/(L of serum NIST used to prepare the sample). 

E4
Vitamin C Round Robin 18 

NIST Micronutrient Measurement Quality Assurance Program
 

Preparation and Validation of Control Samples
 

STOCK SOLUTION 

Mass of ascorbic acid in the Stock Solution ..................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask.................__________ g 

DILUTE SOLUTION 1 

Mass of added stock solution (0.5 mL) ..........................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask .................__________ g 

Absorbance of Dilute Solution 1 at 242 nm...................................................__________ AU
 

Absorbance of Dilute Solution 1 at 243 nm...................................................__________ AU
 

Absorbance of Dilute Solution 1 at 244 nm...................................................__________ AU
 

Absorbance of Dilute Solution 1 at 245 nm...................................................__________ AU
 

Absorbance of Dilute Solution absorbance maximum ..................................__________ AU
 

Wavelength of maximum absorbance............................................................__________ nm
 

Calculated E1% ...............................................................................................__________ dL/g·cm
 

Calculated [TAA] DS1 .....................................................................................__________ μmol/L
	

DILUTE SOLUTION 2 

Mass of added stock solution (0.25 mL) ........................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask .................__________ g 

Calculated [TAA] DS2 .....................................................................................__________ μmol/L
	

DILUTE SOLUTION 3 

Mass of added stock solution (0.125 mL) ......................................................__________ g 

Mass of 5% MPA Diluent added to the 100 mL volumetric flask .................__________ g 

Calculated [TAA] DS3 .....................................................................................__________ μmol/L
	

E5
Vitamin C Round Robin 18 

NIST Micronutrient Measurement Quality Assurance Program 

Analysis of Control and Test Samples 

Sample Replicate 1 Replicate 2 Units 

Dilute Solution 1 μmol/L of Dilute Solution 

Dilute Solution 2 μmol/L of Dilute Solution 

Dilute Solution 3 μmol/L of Dilute Solution 

5% MPA Diluent μmol/L of Diluent 

Test Sample #32 μmol/L of Sample 

Test Sample #45 μmol/L of Sample 

Test Sample #67 μmol/L of Sample 

Were samples frozen upon receipt? Yes | No 

Was SRM 970 used to validate your method or value-assign your in-house controls? Yes | No 

Analysis method: HPLC-EC | HPLC-Fluor DAB | HPLC-OPD | HPLC-UV | AO-OPD | Other 

If “Other”, please describe: 

COMMENTS: 

E6
 

 

Vitamin C Round Robin 18 

NIST Micronutrients Measurement Quality Assurance Program 

Packing List and Shipment Receipt Confirmation Form 

This box contains one vial each of the following four VitC M2QAP samples: 

Sample Form 

VitC #32 Liquid frozen (1:1 serum:10% MPA) 

VitC #45 Liquid frozen (1:1 serum:10% MPA) 

VitC #67 Liquid frozen (1:1 serum:10% MPA) 

Control Solid AA 

Please 1) Open the pack immediately
 

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

3) Check if samples VitC #32, #45, and #67 arrived frozen
 

4) Store the samples 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 four vials intact? Yes | No 

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

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

4) Did samples VitC #32, #45, and #67 arrive frozen? Yes | No 

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

6) When do you anticipate analyzing these samples? ________________________ 

Your prompt return of this information is appreciated. 

The M2QAP Gang 

E7
 

 

Appendix F. Final Report for RR18 

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
March 28, 2003 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-0001 

Enclosed is the summary report of the results for Round Robin 18 (RR18) 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 and a summary of individual laboratory 

performance and interlaboratory accuracy and repeatability. As in previous reports, the estimated 

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

estimate coefficients of variation ( eCV) are defined as 1 OOx eSD/median. 

RR18 consists of three unknowns (test samples) and one solid reference ascorbic acid for 

preparation of control solutions. Details regarding the samples can be found in the enclosed report. 

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

analyze a unit of Standard Reference Material (SRM) 970, Vitamin C in Frozen Human Serum. 

SRM 970 can be purchased from the NIST SRM Program 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. 

Samples for a second vitamin C round robin study (RR 19) will be shipped, at no additional cost to 

you, during the week of April 7. We will send you a reminder via e-mail or fax a week prior to 

shipment. It is critical that you carefully inspect all samples upon arrival and that you promptly 

confirm to us that they have arrived. We will replace samples (lost or damaged in shipment or 

miss-packaged by us) only for participants who report the problem within one calendar week after 

the package arrives. 

If you have questions or concerns regarding this report, please contact me at 301-975-3120; e-mail: 

jbthomas@n.ist.gov; or fax: 301-977-0685. 

ice Brown Thomas 

esearch Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

NlSI 

F2
The NIST M2

QAP Vitamin C Round Robin 18 (RR18) report consists of 

Page “Individualized” Report 

1 Summarizes your reported values for the nominal 55 mmol/L solution you prepared from 

the solid ascorbic acid control sample and for three recently prepared test samples. 

2 Graphical summary of your RR 18 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR18 

samples and control/calibration solutions. 

Test Samples. Three unknowns were distributed in RR18. 

S18:1 Serum 32, previously distributed as sample S17:2 (RR17, Sep-02). 

S18:2 Serum 45, initial distribution. 

S18:3 Serum 67, SRM 970 level 2. This material was distributed with identification in RR11 (Oct98) and RR12 (Mar-99) and as samples S13-2 (RR13, Mar-00), S14-4 (RR14, Mar-01), and 

S15:2 (RR15, Sep-01) 

Results. 

1)	 All participants successfully prepared the four control/calibration solutions (the three dilute solutions 

and the 5% MPA diluent). The criteria used to evaluate this success are: the density of the 5% MPA 

(≈1.03 gm/mL), the observed wavelength maximum of “Dilute Solution #1”(≈244 nm), the observed 

absorbance at that maximum (≈0.55 OD), the calculated E1% #1”(≈550 dL/g·cm). 

2)	 Judging from the calibration parameters calculated for the control/calibration solutions (intercepts 

close to 0.0 and slopes close to 1.0), the measurement systems for most participants are well 

calibrated. The overall among-participant agreement (concordance) was pretty much unchanged by 

“correcting” the reported test sample results with the observed calibration parameters. 

3)	 There has been little if any change in the TAA level in Serum 32 over the past six months. There has 

been little if any change in the TAA level in SRM 970 level 2 over the past five years. 

4)	 The among-participant 10% to 14% relative standard deviations for these materials are as expected 

from past experience (see the RR17 report). 

F3
Appendix G. “All-Lab Report” for RR18 

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. 

G1
 

 

Micronutrients Measurement Quality Assurance Program for Total Ascorbic Aci

"Round Robin" 18 - March 2003 

Control / Calibration Samples MPA Dilute Solution 1 

G2

Calibration Parameters Density Spectrophotometry Measu

Gravimetric, μmol/L Measured, μmol/L 

E1% Lab Date Dil:1 Dil:2 Dil:3 Dil:1 Dil:2 Dil:3 MPA Inter Slope R2 SEE g/mL S18:1 S

λmax Amax 

VC-MA 20/03/03 51.3 25.4 12.2 52.6 25.7 12.5 0.0 -0.054 1.02 1.000 0.2 1.030 244. 0.5093 563.1 23.2 

VC-MB 19/12/02 59.5 30.0 14.9 50.1 23.5 13.9 0.3 0.363 0.83 0.997 1.5 1.032 245. 0.5922 564.6 21.4 

VC-MC 02/12/02 55.6 25.8 11.9 53.2 26.9 13.2 0.0 1.196 0.95 0.997 1.4 1.027 243. 0.5178 528.5 23.3 

VC-ME 14/03/03 56.7 28.0 13.8 55.8 26.9 13.6 1.4 0.734 0.96 0.999 0.9 1.028 243. 0.5709 572.0 18.7 

VC-MG 26/02/03 57.0 29.4 14.6 55.0 27.8 14.1 0.0 -0.101 0.96 1.000 0.3 1.031 243.7 0.5410 539.3 23.0 

VC-MH 14/02/03 61.4 31.0 14.9 59.7 32.1 14.4 0.0 0.334 0.98 0.999 1.2 1.031 243.4 0.6151 568.8 21.2 

VC-MI 20/02/03 55.2 28.0 13.7 55.8 26.8 14.2 0.0 -0.160 1.01 0.999 1.1 1.030 19.6 

VC-MO 28/02/03 58.6 29.0 14.4 17.3 1.20 1.032 243. 0.5720 554.4 26.2 

VC-MQ 03/04/03 58.5 29.3 14.9 55.4 28.1 14.0 0.0 0.005 0.95 1.000 0.3 1.028 244. 0.5680 551.6 20.4 

VC-MR 26/11/02 59.4 29.3 14.7 59.1 29.3 14.7 0.0 0.003 1.00 1.000 0.1 1.029 244. 0.5800 554.6 21.8 

VC-MS 14/01/03 56.5 27.5 14.0 21.5 11.8 0.0 0.276 0.78 0.998 0.7 1.029 243. 0.5479 550.6 19.2 

VC-MT 10/12/02 57.0 28.9 14.4 59.0 30.9 14.3 0.0 -0.032 1.04 0.999 0.8 1.031 244. 0.5677 565.0 16.3 

VC-MY 20/11/02 56.9 28.1 14.1 62.5 24.4 12.5 0.0 -2.493 1.10 0.987 3.8 1.031 14.2 

NIST 17/12/02 60.0 26.6 14.9 57.1 25.6 14.9 0.0 0.346 0.95 1.000 0.4 1.032 244. 0.5614 531.7 21.4 

N 13 13 13 

57.2 28.4 14.0 

2.5 1.6 1.0 

51.3 25.38 11.9 

56.5 28.03 13.8 

57.0 28.93 14.4 

58.6 29.32 14.7 

61.4 31.01 14.9 

2.2 1.33 0.7 

4 5 5 

11 12 13 12 

56.2 27.0 13.9 0.1 

3.6 3.0 1.3 0.4 

50.1 21.55 11.8 0.0 

54.1 25.39 13.2 0.0 

55.8 26.95 14.0 0.0 

59.0 28.39 14.3 0.0 

62.5 32.05 17.3 1.4 

4.7 2.62 0.6 0.0 

8 10 4 

N 13 11 11 11 13 

Average Average 1.030 243.6 0.5620 555.7 20.7 

SD SD 0.002 0.6 0.0311 13.1 3.2 

Min Min 1.027 243.0 0.5093 528.5 14.2 

%25 %25 1.029 243.0 0.5445 551.1 19.2 

Median Median 1.030 243.7 0.5680 554.6 21.2 

%75 %75 1.031 244.0 0.5760 564.8 23.0 

Max Max 1.032 245.0 0.6151 572.0 26.2 

eSD eSD 0.001 0.4 0.0298 14.8 3.0 

eCV CV 0.12 0.18 5 3 14 

All Lab Report 
Appendix H. Representative “Individualized Report” for RR18 

Each participant in RR18 received an “Individualized Report” reflecting their reported 

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

“VC-MA”. 

H1
 

Set 1 of 14 

Vitamin C "Round Robin" 18 Report: Participant VC-MA
 

Date RR Method 

09/17/01 13 HPLC-EC 

09/27/01 14 HPLC-EC 

09/18/01 15 HPLC-EC 

11/18/02 16 HPLC-EC 

12/12/02 17 HPLC-EC 

03/20/03 18 HPLC-EC 

Mean 

SD 

CV 

Date RR Sample 

12/12/02 17 S17:2 

03/20/03 18 S18:1 

MPA Dilute Solution 1 Control/Calibration Solutions 

Density Spectrophotometry Ymeas = Inter + Slope* Xgrav 

g/mL 

1.031 

1.028 

1.027 

1.032 

1.026 

1.026 

λmax Amax E1% Inter Slope R2 SEE 

244.0 0.523 572.5 

243.0 0.541 547.7 -0.9 1.03 0.999 1.09 

243.0 0.547 556.5 0.0 1.04 1.000 0.05 

242.0 0.575 576.5 -0.4 1.07 0.999 0.90 

242.0 0.552 551.0 -0.3 1.06 1.000 0.49 

244.0 0.509 563.1 -0.1 1.02 1.000 0.18 

1.028 242.8 0.54 559.0 

0.002 0.8 0.02 11.4 

0.23 0.34 4.4 2.0 

[TAA] mmol/Lsample 

Rep1 Rep2 Fadj Mean SDdup N Mean SDrepeat SDreprod 

23.3 23.4 1.0 23.4 0.1 2 23.3 0.5 0.4 

22.7 23.7 1.0 23.2 0.7 

03/20/03 18 S18:2 35.1 36.0 1.0 35.6 0.6 

09/23/98 11 S11:2:A 50.7 47.7 0.5 24.6 1.1 

09/23/98 11 S11:2:B 48.8 54.0 0.5 25.7 1.8 

04/02/99 12 S12:2:A 49.5 45.9 0.5 23.9 1.3 

04/02/99 12 S12:2:B 46.2 47.9 0.5 23.5 0.6 

09/17/01 13 S13:2 27.6 27.7 1.0 27.7 0.1 

09/27/01 14 S14:4 25.7 26.4 1.0 26.0 0.5 

09/18/01 15 S15:2 25.4 25.6 1.0 25.5 0.2 

03/20/03 18 S18:3 28.8 29.2 1.0 29.0 0.3 

8 25.7 0.9 1.9 

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 Fax: (301) 977-0685 

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

Individualized Report Page 1 / 2 

H2
 

 

 

 

 

 

Set 1 of 14 

Vitamin C "Round Robin" 18 Report: Participant VC-MA 

Total Ascorbic Acid 

[Total Ascorbic Acid], μmol/L 

Your [Total Ascorbic Acid], μmol/L

S17:2S18:1S18:2S11:2S12:2S13:2S14:4S15:2S18:3 

Median [Total Ascorbic Acid], μmol/L 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, RR 18 NIST, RR 18 Median (50%) You, RR 13-17 Others, RR 18 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 

S18:1 Serum 32, previously distributed in RR 17 

S18:2 Serum 45, initial distribution 

S18:3 SRM 970 Level 2, previously distributed as in RRs 11, 12, 13, 14, and 15 

Individualized Report Page 2 / 2 

H3