NISTIR 7880-8

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2008 

Comparability Studies 

Results for Round Robin LXIV 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 29 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

 

 

 

NISTIR 7880-8
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2008 

Comparability Studies 

Results for Round Robin LXIV 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 29 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

Chemical Sciences Division 

Materials Measurement Laboratory 

April, 2013 

U.S. Department of Commerce 

Rebecca Blank, 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 

Summer 2008 MMQAP measurement comparability improvement studies: 1) Round Robin LXIV 

Fat-Soluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 29 Total Ascorbic Acid 

in Human Serum. The materials for both studies were shipped to participants in May 2008; 

participants were requested to provide their measurement results by September 12, 2008. 

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

Round Robin 29: Vitamin C in Human Serum............................................................................... 2
 

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

Appendix A. Shipping Package Inserts for RR64........................................................................ A1
 

Appendix B. Final Report for RR64 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR64 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR64 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR29 ......................................................................... E1
 

Appendix F. Final Report for RR29............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR29..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR29............................................... 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 LXIV: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

LXIV comparability study (hereafter referred to as RR64) 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 

May 2008. 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 RR64 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 29: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 29 comparability study 

(hereafter referred to as RR29) received four frozen serum test samples, one frozen control serum, 

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 May 2008. The communication materials included in the sample shipment 

are provided in Appendix E. 

The test and control 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 RR29 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 RR64 

The following three items were included in each package shipped to an RR64 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
May 12, 2008 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute at Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed are the samples (Sera 347-351) forthe second fat-soluble vitamins and carotenoids in serum 

round robin study (Round Robin LXN) for the fiscal year (FY) 08 NIST Micronutrients Measurement 

Quality Assurance Program. You will find one vial of each of three liquid-frozen serum samples and two 

lyophilized 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 a value is obtained below 

your limit of quantification, please indicate this result on the form by using NQ (Not Quantified). Results 

are due to NIST by September 12, 2008. Results received more than two weeks after the due date will 

not be included in the summary report for this round robin study. For your convenience, we have also 

included one vial of Serum 198 (which was distributed in four past round robin studies) that can be used 

as a control and to help validate your method. We have included the averaged assigned values for the 

measurands in this serum as well. 

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 mteriiiittenfContact of the liql.iid sample wifh-thestopper. 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. 

For consistency, we request that laboratories use the following absorptivities (dLJg.cm): retinal, 1843 at 

325 nm (ethanol); retinyl palmitate, 975 at 325 run (ethanol); a.-tocopherol, 75.8 at 292 nm (ethanol); ytocopherol, 91.4 at 298 nm (ethanol); a-carotene, 2800 at 444 nm (hexane); ~-carotene, 2560 at 450 nm 

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

Please mail or fax your results 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, the above address. 

l anic Brown Thomas 

ese ch Chemist 

An ytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

A2
c 

Reference Values for NIST Serum 198, μg/mL 

Analyte Valuea U95 

b P95 c 

Total Retinol 0.73 0.02 0.11 

Retinyl Palmitate 0.25 0.04 0.14 

α-Tocopherol 14.1 0.3 2.0 

β/γ-Tocopherol 2.57 0.06 0.31 

Total β-Carotene 0.68 0.01 0.15 

trans- β-Carotene 0.634 0.006 0.093 

Total cis- β-Carotene 0.055 0.011 0.036 

Total α-Carotene 0.039 0.007 0.020 

Total Lycopene 0.155 0.030 0.079 

trans-Lycopene 0.070 0.008 0.031 

Total β-Cryptoxanthin 0.019 0.004 0.012 

Total Lutein 0.052 0.003 0.019 

Total Zeaxanthin 0.020 0.003 0.011 

Total Lutein&Zeaxanthin 0.073 0.006 0.030 

a	 Expected value; the average of the interlaboratory median results and mean of NIST results 

in M2QAP RR31, RR35, RR43, and RR57 

b Approximate 95% uncertainty interval; the interval Value ± U95 is believed with 

approximately 95% confidence to contain the true value of the analyte 

Approximate 95% prediction interval; the interval Value ± P95 contains approximately 95% 

of valid measurements obtained with measurement systems similar to those in use in M2

QAP 

RR31, RR35, RR43, and RR57 

A3
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LXIV: Human Sera 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 347 348 349 350 351 Units* 

total retinol 

trans-retinol 

didehydroretinol 

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

 total coenzyme Q10 

ubiquinol (QH2) 

ubiquinone (Qox) 

phylloquinone (K1) 

25-hydroxyvitamin D 

Other measurands? 

* we prefer μg/mL 

Were the liquid-frozen samples (349 to 351) frozen when received? Yes | No 

Comments: 

Mail: M2QAP
 

NIST, Stop 8392 Please return results before 12-Sep-2008 Fax: 301-977-0685
 

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

A4
 

 

 

 

Participant #: ________ Date: _____________ 

Fat-Soluble Vitamins Round Robin LXIV
 

NIST Micronutrients Measurement Quality Assurance Program
 

Packing List and Shipment Receipt Confirmation Form 

This box contains: one vial each of the following five FSV M2QAP sera 

Serum 

#347 

#348 

Form 

Lyophilized 

Lyophilized 

Reconstitute? 

Yes (1 ml H2O) 

Yes (1 ml H2O) 

Vial/Cap 

5 mL clear, silver 

2 mL amber, blue 

#349 Liquid frozen No 2 mL amber, silver 

#350 Liquid frozen No 2 mL amber, silver 

#351 Liquid frozen No 10 mL amber, silver 

Please 1) Open the pack immediately 

2) Check that it contains all of the above samples 

3) Check if the vials are intact 

4) Store the sera 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 sera vials intact? Yes | No 

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

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

4) Did the liquid frozen samples arrive frozen? Yes | No 

5) At what temperature are you storing the serum 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 

A5
 

 

 

Appendix B. Final Report for RR64 

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. 

B1
November 20, 2008 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed is the summary report of the results for round robin LXN (RR64) of the 2008 NIST 

Micronutrients Measurement Quality Assurance Program (M2QAP) for the fat-soluble vitamins and 

carotenoids in human serum. Included in this report are: 1) a summary of data and measurement 

comparability scores for all·laboratories, 2) a detailed graphical analysis of your results; and 3) a 

graphical summary of your measurement co1:11parability. 

Your overall measurement comparability is summarized in the "Score Card" summary, page 6 of the All 

Lab Report. Combined results rated 1to3 are within 1 to 3 standard deviations of the assigned value, 

respectively; those rated 4 are > 3 standard deviations from the assigned value. Similar information is 

presented graphically in the "target plots" that are the last page of your Individualized Report. If you · 

have concerns regarding your laboratory's performance, please contact us for consultation. 

We have received your inquiries regarding the availability of the renewal material SRM 968d, FatSoluble Vitamins, Carotenoids, and Cholesterol in Human Serum. The material has been value-assigned. 

Our SRM office is c~rrently finalizing the packaging of the SRM prior to sale. Orders can be placed 

directly through our on-line SRM order request system at: https://srmors.nist.gov/index.cfrn. You can 

• also call the SRM office directly at (301) 975-2200 for more details regarding the SRM's availability. 

Samples for the first 2009 QA inter laboratory exercise will be shipped during the week of December 8, 

2009. If you have any questions regarding this report, please contact Dave Duewer at 

david.duewer@nist.gov or me atjbthomas@nist.gov, tel: 301/975-3120, or fax: 301/977-0685. 

I 

I l)L-' / 

ea ice Brown Tho:r;nas 

Re earch Chemist 

A alytical Chemistry Division 

. emical Science and Technology Laboratory 

Cc: L.C. Sander 

D.L. Duewer 

NISI 

B2
 

 

 

 

 

 

 

The NIST M2QAP Round Robin LXIV (RR64) report consists of: 

Page “All Lab” Report 

1-4 A listing of all results and statistics for all analytes. 

5 A legend for the list of results and statistics. 

6 The text Comparability Summary (“Score Card”) of measurement performance. 

Page “Individualized” Report 

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 8 other participants. 

n+1 The graphical Comparability Summary (target plot) of measurement performance. 

Samples. Five samples were distributed in RR64. 

Serum Description Prior Distributions 

347 Lyophilized, augmented, multi-donor serum #195:RR31-6/94, #214:RR35-9/95;
 

prepared in 1994. This material is a 1:1 blend of #244:RR43-6/98, #328:RR60-9/06 

stripped serum and a serum pool augmented with 

retinol, retinyl palmitate, and α-tocopherol.
 

348 Lyophilized, native, single-donor, commercially #290:RR53-2/03, #300:RR55-3/04, 

obtained serum prepared in 2002. The same #312:RR57-3/05, #322:RR59-3/06, 

material was used to prepare #349. #333:RR61-3/07 

349 Fresh-frozen, native, single-donor, commercially #292:RR53-2/03, #301:RR55-3/04, 

obtained serum prepared in 2002. The same #313:RR57-3/05, #323:RR59-3/06, 

material was used to prepare #348. #332:RR61-3/07 

350 Fresh-frozen, native, multi-donor plasma #340:RR63-3/08
 

commercially prepared in 2006.
 

351 Fresh-frozen, native, multi-donor serum prepared in #341 & #344:RR63-3/08 

Fall, 2007 (SRM 968d) 

Results 

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

measurand in any of the lyophilized or fresh-frozen materials. 

2)	 Candidate SRM 1950, Metabolites in Human Plasma (#350). As in RR63, no analysis problems were 

reported for this material. We anticipate this material being available for purchase mid-2009. 

3)	 SRM 968d Fat-Soluble Vitamins and Carotenoids in Human Serum (#351). As in RR63, no analysis 

problems were reported for this material. It will be available for purchase in the near future. 

B3
 

 

Appendix C. “All-Lab Report” for RR64 

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

exceptions: 

• the participant identifiers (Lab) have been altered. 

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

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

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

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

summary results of the study. 

C1
Round Robin LXIV Laboratory Results 

Total Retinol, μg/mL trans-Retinol, μg/mL Retinyl Palmitate, μg/mL α-Tocopherol, μg/mL γ/β-Tocopherol, μg/mL 

Lab 347 348 349 350 351 

C2

FSV-BA 0.409 0.633 0.665 0.431 0.356 

FSV-BB 0.429 0.680 0.679 0.438 0.396 

FSV-BC 0.355 0.630 0.673 0.419 0.370 

FSV-BD 0.407 0.589 0.604 0.413 0.334 

FSV-BE 0.448 0.696 0.746 0.464 !0.294 

FSV-BF 0.350 0.590 0.600 0.410 0.330 

FSV-BG 0.383 0.607 0.644 0.428 0.358 

FSV-BH 0.305 0.558 0.620 0.381 0.312 

FSV-BI 0.385 0.583 0.616 0.397 0.323 

FSV-BJ 0.368 0.545 0.606 0.385 0.314 

FSV-BK 0.472 0.702 0.738 0.526 0.470 

FSV-BL 0.340 0.660 0.690 0.430 0.340 

FSV-BM 0.350 0.620 0.650 0.420 0.350 

FSV-BN 0.364 0.548 0.554 0.372 0.314 

FSV-BO 0.344 0.739 0.633 0.464 0.438 

FSV-BP 0.444 0.633 0.648 0.447 0.358 

FSV-BQ 0.382 0.634 0.656 0.425 0.323 

FSV-BR ≥0.420 ≥0.690 ≥0.630 ≥0.430 ≥0.340 

≥0.392 ≥0.424 ≥0.353 ≥0.592 ≥0.694 FSV-BS 

FSV-BT 0.409 0.661 0.568 0.440 0.438 

FSV-BU 0.342 0.557 0.606 0.442 0.324 

FSV-BV 0.305 0.642 0.648 0.394 0.330 

FSV-BW 0.400 0.620 0.690 0.430 0.350 

FSV-CD 0.320 0.550 0.570 0.370 0.290 

FSV-CE 0.380 0.660 0.700 0.450 0.340 

FSV-CF 0.447 0.685 0.724 0.483 0.394 

FSV-CG 0.369 0.625 0.608 0.401 0.336 

FSV-CI 0.288 0.676 0.701 0.458 0.379 

FSV-CW 0.350 0.593 0.605 0.404 0.339 

FSV-CZ 0.322 0.552 0.565 0.363 0.314 

FSV-DD 0.360 0.530 0.580 0.360 0.300 

FSV-DQ 

FSV-DV ≥0.386 ≥0.603 ≥0.641 ≥0.407 ≥0.334 

FSV-EE 0.335 0.562 0.569 0.366 0.291 

347 348 349 350 351 

0.420 0.690 0.630 0.430 0.340 

0.392 0.424 0.353 0.592 0.694 

0.386 0.603 0.641 0.407 0.334 

347 348 349 350 351 

0.091 0.070 0.087 0.023 0.025 

0.079 0.066 0.067 0.012 0.007 

0.101 0.094 0.104 0.014 nd 

0.116 0.102 0.102 nd nd 

0.116 0.071 0.082 nq nq 

0.122 0.084 0.088 0.026 0.018 

0.143 0.122 0.131 0.017 0.007 

0.152 0.093 0.109 0.015 <0.02 

0.076 0.069 0.070 0.013 0.005 

347 348 349 350 351 

7.11 9.04 9.59 7.78 5.80 

6.94 10.19 10.30 8.02 5.99 

7.90 10.30 10.80 9.30 6.10 

6.99 9.37 9.80 7.46 !0.47 

7.00 10.00 10.20 8.50 6.20 

7.30 10.13 10.68 8.54 6.49 

7.73 10.96 11.58 9.04 6.60 

6.52 10.03 10.53 8.16 5.80 

7.58 9.94 11.04 8.60 6.06 

7.35 10.45 11.25 9.18 6.45 

6.46 9.48 9.91 7.75 5.60 

6.80 10.60 10.80 9.00 5.90 

6.09 8.50 8.61 6.99 4.90 

6.68 10.21 10.98 8.61 6.42 

7.89 9.21 10.30 9.44 5.42 

6.99 8.74 9.00 6.89 4.70 

6.26 8.35 7.70 6.22 3.00 

7.27 10.18 10.99 8.70 4.93 

5.06 11.09 10.60 7.19 4.19 

7.05 10.62 10.14 7.45 4.88 

7.68 10.09 11.17 8.88 6.08 

7.35 10.45 10.84 8.66 5.94 

7.80 5.50 12.10 9.70 6.00 

7.40 10.10 10.70 8.90 5.80 

6.61 9.51 9.54 7.14 nd 

8.07 10.24 11.09 8.45 5.88 

6.97 10.29 10.90 8.62 6.21 

6.39 10.92 8.62 7.92 3.48 

7.72 8.43 11.02 8.22 5.42 

5.40 8.90 9.60 7.30 5.00 

7.10 10.40 10.70 8.50 5.40 

347 348 349 350 35

1.35 1.63 1.74 1.73 1.4

1.29 1.67 1.71 1.65 1.3

1.33 1.72 1.86 1.75 !0.5

1.36 1.82 1.87 1.87 1.5

1.32 1.73 1.86 1.76 1.4

1.40 1.80 1.91 1.86 1.5

1.31 1.56 1.75 1.74 1.4

1.22 1.59 1.63 1.62 1.3

1.22 1.71 1.75 1.74 1.4

1.31 1.72 1.82 1.79 1.1

1.42 1.61 1.75 1.93 1.3

1.19 1.71 1.67 1.55 1.2

1.21 1.53 1.66 1.61 1.3

1.21 1.69 1.75 1.73 1.3

1.28 1.78 1.79 1.78 0.8

1.61 1.86 1.99 1.95 1.6

1.37 1.79 1.91 1.85 1.5

1.77 2.20 2.20 2.45 1.6

1.34 1.57 1.84 1.71 1.4

N 30 30 30 30 29 3 3 3 3 3 9 9 9 7 5 31 31 31 31 29 19 19 19 19 1

Min 0.288 0.530 0.554 0.360 0.290 0.386 0.424 0.353 0.407 0.334 0.076 0.066 0.067 0.012 0.005 5.06 5.50 7.70 6.22 3.00 1.19 1.530 1.63 1.55 0.8

Median 0.366 0.623 0.638 0.423 0.339 0.392 0.603 0.630 0.430 0.340 0.116 0.084 0.088 0.015 0.007 7.05 10.10 10.68 8.50 5.80 1.32 1.710 1.79 1.75 1.4

Max 0.472 0.739 0.746 0.526 0.470 0.420 0.690 0.641 0.592 0.694 0.152 0.122 0.131 0.026 0.025 8.07 11.09 12.10 9.70 6.60 1.77 2.196 2.20 2.45 1.6

SD 0.047 0.069 0.054 0.035 0.026 0.023 0.018 0.016 0.005 0.009 0.63 0.79 0.84 0.88 0.80 0.09 0.125 0.09 0.10 0.1

CV 13 11 9 8 8 20 21 18 32 121 9 8 8 10 14 7 7 5 6 

Npast 41 33 33 30 30 5 7 7 7 7 11 11 11 9 9 42 35 36 36 34 21 22 22 24 2

Medianpast 0.381 0.608 0.642 0.423 0.348 0.429 0.611 0.644 0.405 0.332 0.114 0.094 0.099 0.013 0.011 7.04 9.89 10.42 7.95 5.74 1.33 1.75 1.83 1.77 1.4

SDpast 0.042 0.043 0.045 0.023 0.021 0.060 0.037 0.048 0.038 0.043 0.025 0.019 0.020 0.004 0.007 0.70 0.70 0.65 0.82 0.84 0.12 0.14 0.16 0.12 0.1

0.335 0.602 0.647 0.408 0.337 6.61 10.11 10.93 8.00 6.09 1.3 1.8 1.8 1.8 1

Srep 0.015 0.030 0.009 0.005 0.005 0.12 0.19 0.20 0.02 0.22 0.0 0.0 0.0 0.0 0

Shet 0.030 0.027 0.001 0.006 0.003 0.12 0.12 0.02 0.02 0.10 0.0 0.0 0.0 0.0 0

SNIST 0.033 0.040 0.009 0.008 0.006 0.17 0.22 0.20 0.03 0.24 0.0 0.0 0.0 0.0 0

NAV 

MeanNIST 

0.350 0.612 0.643 0.415 0.338 0.392 0.603 0.630 0.430 0.340 0.116 0.084 0.088 0.015 0.007 6.83 10.11 10.81 8.25 5.94 1.33 1.75 1.82 1.79 1.4

NAU 0.052 0.070 0.055 0.036 0.028 0.029 0.023 0.024 0.011 0.010 0.70 0.79 0.86 0.95 0.83 0.15 0.19 0.20 0.20 0.1

All Lab R eport 
Round Robin LXIV Laboratory Results 

Total β-Carotene, μg/mL trans-β-Carotene, μg/mL Total cis-β-Carotene, μg/mL Total α-Carotene, μg/mL Total Lycopene, μg/m

Lab 347 348 349 350 351 

C3

FSV-BA 0.348 0.111 0.122 0.081 0.084 

FSV-BB 0.309 0.107 0.110 0.073 0.075 

FSV-BC 

FSV-BD 

FSV-BE 0.175 0.084 0.079 0.068 !0.0387 

FSV-BF 0.367 0.099 0.099 0.064 0.075 

FSV-BG 0.354 0.146 0.153 0.087 0.093 

FSV-BH 0.371 0.118 0.121 0.075 0.078 

FSV-BI 0.325 0.117 0.116 0.074 0.070 

FSV-BJ 0.314 0.107 0.110 0.061 0.069 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.320 0.108 0.108 0.072 0.077 

FSV-BO 0.373 0.136 0.127 0.083 0.089 

FSV-BP 0.064 0.070 0.082 0.090 0.040 

FSV-BQ 

FSV-BR 

FSV-BS ≥0.314 ≥0.123 ≥0.115 ≥0.057 ≥0.067 

FSV-BT 0.382 0.128 0.127 0.094 0.094 

FSV-BU 0.341 0.126 0.135 0.083 0.083 

FSV-BV 0.330 0.123 0.124 0.067 0.067 

FSV-BW 0.400 0.130 0.145 0.083 0.082 

FSV-CD 0.422 0.197 0.201 0.168 0.182 

FSV-CE 0.280 0.031 0.140 0.110 0.070 

FSV-CF 

FSV-CG 0.301 0.112 0.113 0.066 0.054 

FSV-CI 0.294 0.106 0.114 0.057 0.050 

FSV-CW 0.340 0.132 0.135 0.084 0.090 

FSV-CZ 

FSV-DD 

FSV-DQ 0.378 0.052 0.088 0.061 0.053 

FSV-DV 0.309 0.136 0.135 0.089 0.078 

FSV-EE 

347 348 349 350 351 

0.315 0.107 0.118 0.076 0.080 

0.287 0.103 0.105 0.070 0.071 

0.346 0.118 0.121 0.075 0.078 

0.279 0.100 0.100 0.066 0.069 

0.289 0.116 0.108 0.077 0.084 

0.314 0.123 0.115 0.057 0.067 

0.355 0.123 0.122 0.089 0.088 

0.274 0.103 0.106 0.061 0.048 

347 348 349 350 351 

0.033 0.004 0.004 0.005 0.004 

0.022 0.004 0.004 0.004 0.004 

0.025 nq nq nq nq 

0.038 0.006 0.004 0.003 0.005 

0.084 0.020 0.019 0.005 0.005 

0.033 0.007 0.007 0.007 0.007 

0.028 0.009 0.007 0.006 0.006 

347 348 349 350 351 

0.016 0.073 0.080 0.026 0.009 

0.015 0.065 0.066 0.022 0.008 

0.017 0.085 0.091 0.024 0.010 

nq 0.086 0.090 nq nq 

0.014 0.072 0.078 0.025 0.007 

0.029 0.080 0.092 0.020 0.015 

- 0.072 0.078 0.024 0.008 

0.018 0.079 0.089 0.026 0.005 

nd 0.031 0.038 0.014 0.013 

0.023 0.097 0.104 0.034 0.022 

0.022 0.111 0.110 0.044 0.021 

0.018 0.092 0.097 0.027 0.011 

0.018 0.090 0.090 0.024 0.007 

0.009 0.059 0.065 0.019 0.004 

0.019 0.061 0.071 0.022 <0.005 

0.021 0.091 0.091 0.028 0.007 

0.016 0.055 0.059 0.018 <0.009 

0.020 0.085 0.086 0.026 0.007 

0.013 0.051 0.062 0.011 0.021 

347 348 349 350 

0.079 0.446 0.517 0.328 

0.071 0.474 0.492 0.336 

0.076 0.591 0.621 0.361 

0.075 0.520 0.537 0.347 

0.066 0.396 0.416 0.257 

0.057 0.446 0.579 0.286 

0.069 0.428 0.440 0.288 

0.070 0.504 0.588 0.400 

0.177 0.155 0.152 0.080 

0.048 0.350 0.336 0.191 

0.086 0.453 0.451 0.338 

0.071 0.573 0.570 0.367 

0.070 0.564 0.572 0.310 

0.090 0.616 0.695 0.400 

0.074 0.490 0.496 0.289 

0.160 0.250 0.391 0.267 

N 22 22 22 22 21 8 8 8 8 8 7 6 6 6 6 16 19 19 18 16 16 16 16 16 

Min 0.064 0.031 0.079 0.057 0.040 0.274 0.100 0.100 0.057 0.048 0.022 0.004 0.004 0.003 0.004 0.009 0.031 0.038 0.011 0.004 0.048 0.155 0.152 0.080 

Median 0.335 0.115 0.122 0.078 0.077 0.302 0.112 0.111 0.073 0.075 0.033 0.007 0.005 0.005 0.005 0.018 0.079 0.086 0.024 0.009 0.073 0.464 0.507 0.319 

Max 0.422 0.197 0.201 0.168 0.182 0.355 0.123 0.122 0.089 0.088 0.084 0.020 0.019 0.007 0.007 0.029 0.111 0.110 0.044 0.022 0.177 0.616 0.695 0.400 

SD 0.045 0.017 0.018 0.014 0.011 0.028 0.012 0.010 0.009 0.009 0.007 0.003 0.002 0.001 0.001 0.003 0.019 0.017 0.004 0.005 0.008 0.082 0.103 0.051 

CV 14 15 15 18 14 9 11 9 12 12 21 45 38 23 22 19 23 19 17 56 11 18 20 16 

Npast 31 24 24 22 22 10 11 11 9 9 7 6 6 5 4 24 21 21 17 15 24 21 21 18 

Medianpast 0.341 0.114 0.122 0.075 0.075 0.320 0.110 0.118 0.069 0.075 0.027 0.006 0.007 0.006 0.005 0.019 0.075 0.080 0.027 0.009 0.071 0.483 0.512 0.323 

SDpast 0.043 0.016 0.017 0.012 0.013 0.028 0.011 0.011 0.007 0.007 0.011 0.003 0.002 0.002 0.002 0.006 0.012 0.011 0.005 0.003 0.021 0.054 0.064 0.036 

0.334 0.115 0.129 0.079 0.081 0.015 0.078 0.079 0.032 0.010 nq 0.438 0.432 0.301 

Srep 0.008 0.005 0.004 0.002 0.003 0.002 0.004 0.003 0.003 0.001 0.012 0.004 0.026 

Shet 0.020 0.000 0.006 0.000 0.001 0.001 0.003 0.001 0.001 0.002 0.005 0.012 0.002 

SNIST 0.022 0.005 0.008 0.002 0.003 0.002 0.005 0.003 0.003 0.002 0.013 0.013 0.026 

NAV 

MeanNIST 

0.334 0.115 0.125 0.079 0.079 0.302 0.112 0.111 0.073 0.075 0.033 0.007 0.005 0.005 0.005 0.017 0.079 0.083 0.028 0.009 0.073 0.451 0.469 0.310 

NAU 0.048 0.019 0.021 0.014 0.014 0.032 0.014 0.014 0.011 0.011 0.012 0.003 0.003 0.003 0.003 0.007 0.023 0.025 0.010 0.005 0.022 0.099 0.117 0.073 

All Lab R eport 
Round Robin LXIV Laboratory Results 

Total β-Cryptoxanthin, μg/mL Total α-Cryptoxanthin, μg/mL Total Lutein, μg/mL Total Zeaxanthin, μg/mL Total Lutein&Z

Lab 347 348 349 350 351 

C4

347 348 349 350 351 

0.003 0.029 0.032 0.022 0.019 

0.003 0.022 0.023 0.014 0.015 

0.002 0.013 0.013 0.004 0.007 

347 348 349 350 351 

0.037 0.099 0.101 0.085 0.070 

0.025 0.084 0.088 0.058 0.045 

0.013 0.046 0.036 0.045 0.045 

0.024 0.071 0.074 0.061 0.049 

0.023 0.071 0.079 0.062 0.054 

0.033 0.077 0.079 0.064 0.059 

0.021 0.072 0.073 0.066 0.057 

0.029 0.086 0.075 0.072 0.098 

0.021 0.055 0.054 0.047 0.030 

0.026 0.079 0.080 0.069 0.058 

0.010 0.098 0.101 0.091 0.077 

FSV-BA 0.009 0.064 0.069 0.049 0.046 

FSV-BB 0.010 0.052 0.053 0.036 0.040 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.009 0.063 0.069 0.040 0.050 

FSV-BH nq 0.059 0.062 0.041 0.046 

FSV-BI 0.008 0.051 0.053 0.033 0.036 

FSV-BJ nq 0.037 0.045 0.026 0.032 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.027 0.039 0.040 0.025 0.031 

FSV-BO 0.010 0.048 0.051 0.034 0.044 

FSV-BP 0.008 0.018 0.015 0.025 0.018 

FSV-BQ 

FSV-BR 

FSV-BS 0.016 0.075 0.080 0.041 0.056 

FSV-BT 0.010 0.049 0.050 0.036 0.040 

FSV-BU 0.011 0.048 0.047 0.032 0.034 

FSV-BV 0.007 0.055 0.055 0.033 0.034 

FSV-BW nq 0.052 0.057 0.031 0.038 

FSV-CD 0.006 0.045 0.046 0.032 0.039 

FSV-CE 

FSV-CF 

FSV-CG 0.015 0.077 0.077 0.049 0.047 

FSV-CI 

FSV-CW 0.005 0.051 0.053 0.031 0.036 

FSV-CZ 

FSV-DD 

FSV-DQ 0.016 0.035 0.056 0.034 0.033 

FSV-DV 

FSV-EE 

347 348 349 350 351 

0.014 0.048 0.050 0.037 0.037 

0.008 0.032 0.027 0.018 0.009 

0.006 0.019 0.015 0.015 0.020 

0.010 0.031 0.032 0.021 0.025 

0.009 0.027 0.030 0.017 0.020 

0.006 0.026 0.027 0.022 0.023 

0.012 0.045 0.037 0.029 0.040 

<0.006 0.014 0.018 0.012 0.010 

0.007 0.040 0.043 0.029 0.037 

0.019 0.027 0.027 0.024 0.025 

347 348 

0.036 0.101 

0.051 0.147 

0.030 0.106 

0.019 0.065 

0.034 0.102 

0.039 0.104 

0.027 0.098 

0.054 0.116 

0.026 0.114 

0.041 0.134 

0.030 0.106 

0.037 0.125 

0.033 0.103 

0.059 0.196 

0.044 0.138 

≤0.021 0.069 

0.033 0.119 

0.029 0.125 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

MeanNIST 

Srep 

Shet 

SNIST 

NAV 

NAU 

15 18 18 18 18 

0.005 0.018 0.015 0.025 0.018 

0.010 0.051 0.053 0.034 0.039 

0.027 0.077 0.080 0.049 0.056 

0.004 0.009 0.009 0.006 0.008 

38 18 18 18 22 

17 21 21 18 18 

0.012 0.052 0.055 0.036 0.040 

0.004 0.008 0.010 0.009 0.005 

nq 0.049 0.049 0.034 0.033 

0.000 0.002 0.005 0.001 

0.001 0.001 0.004 0.001 

0.001 0.003 0.006 0.002 

0.010 0.050 0.051 0.034 0.036 

0.004 0.012 0.013 0.009 0.010 

3 3 3 3 3 

0.002 0.013 0.013 0.004 0.007 

0.003 0.022 0.023 0.014 0.015 

0.003 0.029 0.032 0.022 0.019 

6 5 6 5 5 

0.006 0.024 0.026 0.014 0.015 

0.001 0.006 0.006 0.001 0.002 

0.003 0.022 0.023 0.014 0.015 

11 11 11 11 11 

0.010 0.046 0.036 0.045 0.030 

0.024 0.077 0.079 0.064 0.057 

0.037 0.099 0.101 0.091 0.098 

0.005 0.010 0.008 0.008 0.013 

20 13 10 13 23 

12 14 14 12 12 

0.028 0.079 0.081 0.065 0.059 

0.006 0.015 0.014 0.014 0.012 

0.028 0.075 0.076 0.076 0.051 

0.001 0.002 0.003 0.003 0.002 

0.001 0.001 0.004 0.003 0.002 

0.002 0.003 0.005 0.004 0.003 

0.026 0.076 0.077 0.070 0.054 

0.006 0.016 0.016 0.016 0.014 

9 10 10 10 10 

0.006 0.014 0.015 0.012 0.009 

0.009 0.029 0.029 0.021 0.024 

0.019 0.048 0.050 0.037 0.040 

0.003 0.009 0.007 0.008 0.010 

37 29 23 36 43 

9 12 12 10 10 

0.011 0.030 0.031 0.021 0.024 

0.005 0.007 0.008 0.005 0.006 

0.013 0.030 0.031 0.021 0.023 

0.002 0.003 0.003 0.005 0.002 

0.001 0.004 0.003 0.001 0.001 

0.003 0.005 0.004 0.005 0.002 

0.011 0.030 0.030 0.021 0.024 

0.005 0.009 0.008 0.008 0.010 

17 

0.019 

0.034 

0.059 

0.008 

25 

19 

0.039 

0.008 

0.041 

0.004 

0.000 

0.004 

0.037 

0.010 

18 

0.065 

0.110 

0.196 

0.017 

15 

22 

0.109 

0.018 

0.104 

0.001 

0.006 

0.006 

0.107 

0.023 

All Lab R eport 
Round Robin LXIV Laboratory Results 

Coenzyme Q10, μg/mL Phylloquinone (K1), ng/mL 

C5

Lab 347 348 349 350 351 347 348 349 350 351 

FSV-BA 

FSV-BB 

FSV-BC 

FSV-BD 

FSV-BE 0.306 0.764 0.791 0.850 0.786 0.534 0.492 0.466 0.526 0.280 

FSV-BF 

FSV-BG 

FSV-BH 

FSV-BI 

FSV-BJ 0.276 0.697 0.763 0.540 0.573 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.127 0.223 0.252 0.349 0.354 

FSV-BU 

FSV-BV 

FSV-BW 0.356 0.783 0.787 0.633 0.602 

FSV-CD 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 0.310 0.760 0.800 0.850 0.750 0.625 0.421 0.386 0.424 0.206 

FSV-CW 0.109 0.310 0.279 0.247 0.207
 

FSV-CZ
 0.323 0.848 0.696 0.743 0.626 

FSV-DD 

FSV-DQ 

FSV-DV 

FSV-EE 0.285 0.634 0.653 0.700 0.496 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

MeanNIST 

Srep 

Shet 

SNIST 

NAV 

NAU 

8 8 8 8 8 2 2 2 2 2 

0.109 0.223 0.252 0.247 0.207 0.53 0.42 0.39 0.42 0.21 

0.296 0.729 0.730 0.667 0.588 0.58 0.46 0.43 0.48 0.24 

0.356 0.848 0.800 0.850 0.786 0.63 0.49 0.47 0.53 0.28 

0.055 0.160 0.170 0.206 0.146 

19 22 23 31 25 

6 5 5 9 9 

0.350 0.701 0.751 0.683 0.633 

0.018 0.096 0.104 0.166 0.122 

0.296 0.729 0.730 0.667 0.588 

0.055 0.160 0.170 0.206 0.146 

All Lab R eport 
 

 

 

 

 

Term 

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

Min Minimum (non-NIST) quantitative value reported

Median Median (non-NIST) quantitative value reported

Max Maximum (non-NIST) quantitative value reported

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

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

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

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

SDpast Pooled SD from past RR(s)

MeanNIST Mean of NIST results

Srep NIST's within-vial pooled standard deviation

Shet NIST's among-vial pooled standard deviation

SNIST Combined standard deviation for NIST analyses: (Srep 2

 + Shet 2)

0.5

NAV NIST Assigned Value

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

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

NAU NIST Assigned Uncertainty: (S2

 + Sbtw 2)

0.5

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

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

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

- Not analyzed

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

nq Detected but not quantitatively determined

≤x Concentration at or below the limit of quantification, x

≥x Concentration greater than or equal to x

! Discrepant value: heterogeneous serum, damaged sample, malfunction, etc.

italics Not explicitly reported but calculated by NIST from reported values

Round Robin LXIV Laboratory Results
 

Analytes Reported By One Laboratory
 

Analyte Code 347 348 349 350 351 

Ubiquinol FSV-BW 0.277 0.620 0.725 0.568 0.135 

Ubiquinone FSV-BW nq 0.163 0.062 0.065 0.467 

Legend 

All Lab Report Page 5 / 6 

C6
 

 

 

 

 

 

 

Round Robin LXIV Laboratory Results
 

Comparability Summary
 

Lab 

FSV-BA 

FSV-BB 

FSV-BC 

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-CD
 

FSV-CE
 

FSV-CF
 

FSV-CG
 

FSV-CI
 

FSV-CW 

FSV-CZ 

FSV-DD 

FSV-DQ 

FSV-DV 

FSV-EE 

NIST 

n 

% 1
 

% 2
 

% 3
 

% 4
 

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

1 1 1 1 1 1 1 2 1
 

2 1 1 1 1 1 1 1 2 2 2
 

1
 

1 1
 

2 1 1 3
 

1 1 1
 

1 1 1 2 1 1 1 1 1 1
 

1 1 1 1 1 1 1 1 2 2 2
 

1 1 1 1 1 1 1 1 1 1
 

1 1 1 1 2 1 1 1
 

3 1
 

1 1
 

1 1
 

2 2 1 1 1 1 1 3 1 1 1
 

2 1 1 1 1 1 2 1 1 1 1
 

1 2 4 2 4 3 3
 

1 2
 

1 3
 

4 1 1 2 2 2 1
 

2 1 1 1 2 2 1 1 2 2 2
 

1 2 1 1 1 1 1 1
 

1 1 1 1 1 1 1 1
 

1 1 1 1 1 2 1 1
 

2 1 1 4 1 1 4
 

1 4 3
 

2 1
 

1 2 2 1 2 1 1 2 2
 

2 1 2 2 1 2 2 2
 

1 1 1 1 1 1 1 2 1
 

2 2 3
 

2
 

2 1 3 2 3 2 2 2 1
 

1 2 1
 

2 1
 

1 1 1 1 1 1 1 1 1 1
 

34 32 20 24 8 20 17 19 12 11 19
 

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

62 69 85 71 75 75 71 68 58 45 63
 

32 25 10 8 25 25 18 21 42 55 26
 

3 3 5 13 0 0 6 11 0 0 5
 

3 3 0 8 0 0 6 0 0 0 5
 

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) of summarizes your measurement 

performance for a given measurand, relative to the consensus 

medians. CS is the average distance, in standard deviation units, 

that your measurement performance characteristics are from the 

consensus performance. CS is calculated when the number of 

quantitative values you reported for a measurand, Nyou, is at least 

two and the measurand has been reported by 10 or more 

participants. 

CS = MIN(4, INT(1 + C2 + AP 2 )) 

N yo u You − Median C = Concordanc e = i i ∑ Ny ou
 NAU i i
 

N yo u  You i − Median i 

2
 

AP = Apparent Precision = ∑  (Ny ou − 1)   NAU i  i  

NAU = NIST Assigned Uncertainty, our estimate of the overall 

measurement standard deviation for each sample. The 

estimate includes serum heterogeneity, analytical 

repeatability, and among-participant reproducibility variance 

components. 

For further details, please see: Duewer DL, Kline MC, Sharpless 

KE, Brown Thomas J, Gary KT. Micronutrients Measurement 

Quality Assurance Program: Helping participants use 

interlaboratory comparison exercise results to improve their longterm measurement performance. Anal Chem 1999;71(9):1870-8. 

All Lab Report Page 6 / 6
 

C7
 

Appendix D. Representative “Individualized Report” for RR64 

Each participant in RR64 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 RR64: 

• Total Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ/β-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 

• Coenzyme Q10 

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

by participant FSV-BA. 

D1
 

 Set 1 of 40 

Individualized Round Robin LXIV Report: FSV-BA 

Summary 

Serum 347 Serum 348 Serum 349 Serum 350 S

D2

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

Total Retinol 0.409 0.350 30 0.633 0.612 30 0.665 0.643 30 0.431 0.415 30 0.3

Retinyl Palmitate 0.09 0.12 9 0.1 0.1 9 0.1 0.1 9 0.02 0.02 7 0.0

α-Tocopherol 7.11 6.83 31 9.04 10.11 31 9.59 10.81 31 7.78 8.25 31 5.8

γ/β-Tocopherol 1.351 1.333 19 1.629 1.753 19 1.742 1.816 19 1.733 1.792 19 1.4

δ-Tocopherol 0.081 0.075 3 0.046 0.046 3 0.053 0.053 3 0.075 0.075 3 0.0

Total β-Carotene 0.348 0.334 22 0.111 0.115 22 0.122 0.125 22 0.081 0.079 22 0.0

trans-β-Carotene 0.315 0.302 8 0.107 0.112 8 0.118 0.111 8 0.076 0.073 8 0.0

Total cis-β-Carotene 0.033 0.033 7 0.004 0.007 6 0.004 0.005 6 0.005 0.005 6 0.0

Total α-Carotene 0.016 0.017 16 0.073 0.079 19 0.080 0.083 19 0.026 0.028 18 0.0

Total Lycopene 0.079 0.073 16 0.446 0.451 16 0.517 0.469 16 0.328 0.310 16 0.2

trans-Lycopene 0.034 0.034 8 0.259 0.266 8 0.302 0.288 8 0.170 0.148 8 0.1

Total β-Cryptoxanthin 0.009 0.010 15 0.064 0.050 18 0.069 0.051 18 0.049 0.034 18 0.0

Total α-Cryptoxanthin 0.003 0.003 3 0.029 0.022 3 0.032 0.023 3 0.022 0.014 3 0.0

Total Lutein&Zeaxanthin 0.036 0.037 17 0.101 0.107 18 0.104 0.109 18 0.092 0.094 18 0.0

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

NAV : NIST Assigned Values, here equal to this RR's median 

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

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

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology Tel: (

100 Bureau Drive Stop 8392 Fax: (

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

Individualized Report 
NIST, this RR

D3

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Total Retinol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 2 / 14 
NIST, this RR

D4

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Retinyl Palmitate, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 3 / 14 
NIST, this RR

D5

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

α-Tocopherol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 4 / 14 
NIST, this RR

D6

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

γ/β-Tocopherol, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 5 / 14 
NIST, this RR

D7

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Total β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 6 / 14 
NIST, this RR

D8

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

trans-β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 7 / 14 
NIST, this RR

D9

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Total cis-β-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 8 / 14 
NIST, this RR

D10

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Total α-Carotene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 9 / 14 
NIST, this RR

D11

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Total Lycopene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 10 / 14 
NIST, this RR

D12

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

trans-Lycopene, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 11 / 14 
NIST, this RR

D13

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Total β-Cryptoxanthin, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 12 / 14 
NIST, this RR

D14

 Set 1 of 40 

Individualized RR LXIV Report: FSV-BA

Total Lutein&Zeaxanthin, μg/mL 

Apparent Precision, SD [Analyte], μg/mL

195214244328347290300312322333348292301313323332349340350341344351 

Your [Analyte], μg/mL 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, this RR You, ≥x, this RR 

Median [Analyte], μg/mL 

Long-term Precision, SD 

Median (50%) You, past RRs You, ≥x, past RRs Others, this RR 

1st Quartile (25%) Expectation 

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 

#347 31:#195, 35:#214, 43:#244, 60:#328 Lyophilized, multi-donor, aug(TR, RP,aT) 

#348 53:#290, 55:#300,57:#312, 59:#322:RR59,61:#333 Lyophilized, native, single-donor 

#349 53:#292, 55:#301,57:#313, 59:#323:RR59,61:#332 Fresh-frozen, native, single-donor 

#350 63:#340 Plasma, fresh-frozen, native, multi-donor 

#351 63:#341, 63:#344 Fresh-frozen, native, multi-donor 

Individualized Report Page 13 / 14 
D15

 Set 1 of 40 

Individualized Round Robin LXIII Report: FSV-BA 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total α-Carotene T

trans-Retinol γ/β-Tocopherol Total Lycopene Tot

Retinyl Palmitate Total β-Carotene trans-Lycopene Total L

trans-β-Carotene Total β-Cryptoxanthin Co

Individualized Report 
 

 

Appendix E. Shipping Package Inserts for RR29 

The following five items were included in each package shipped to an RR29 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
May 12, 2008 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

The samples within this package constitute Vitamin C Round Robin 29 (RR29) of the 2008 Micronutrients 

Measurement Quality Assurance Program. 

RR29 consists of four vials of frozen serum test samples (#15, #73, #90, and #111 ), one vial of frozen control 

serum (CS #2) and one vial of ascorbic acid solid control material (Control) Please fo_llow the attached 

protocols when you prepare and analyze these samples. If you cannot prepare the solid control solutions 

gravimetrically, please prepare equivalent solutions volumetrically and report the exact volumes used. (Routine 

0.5 g gravimetric measurements are generally 10-fold more accurate than routine 0.5 mL volumetric · 

measurements.) 

Please use the control serum to validate the performance of your measurement system before you analyze the 

test samples. The target value and ~95% confidence interval for target value and ~95% confidence interval for 

CS #2 is 28.1 ±1.0 μmol/L of sample. 

The report for RR28 was mailed May 2, 2008. If you find your results for RR28 unsatisfactory, 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 Materials Reference Program at NIST (Tel: 301-975-6776, Fax: 301-948-3730, or e-mail: 

srminfo@nist.gov). 

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

If you have any questions or concerns about the Vitamin C Micronutrients Measurement Quality Assurance 

Program please contact Jeanice Brown Thomas at tel: 301-975-3120, fax: 301-977-0685, or 

e-mail: jbthomas@nist.gov. 

We ask that you return your results for these RR29 samples before Sep 12, 2008. We would appreciate 

receiving your results as soon as they become available. Please use-the attached form. Your results will be 

kept confidential. 

es 

a ical Chemistry Division 

·c mical Science and Technology Laboratory 

Enclosures: Protocols, Preparation and Analysis of Control Materials and Analysis of Test Samples 

RR29 Report Form for Ascorbic Acid Solid Control Material Preparation 

RR29 Report Form for Control Material and Test Sample Analyses 

NISI 

E2
 

 

 

 

 

 

Micronutrient Measurement Quality Assurance Program for
 

Vitamin C
 

Please Read Through Completely BEFORE Analyzing Samples 

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

The ascorbic acid solid control material (in the amber vial) 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 0.20 to 0.22 g of the ascorbic acid solid control material 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 = 29.4 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 at 242, 243, 244, and 245 nm. 

Record the maximum absorbance (Amax) within this region. Record the wavelength (λmax) at 

which this maximum occurs. 

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: 

E3
 

 

 

 

1% dL (A max )⋅	 ((g AA in Stock Solution ) + (g Diluent in Stock Solution )) 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 recalibrate 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 that you will use for the serum 

control materials and test samples, including any enzymatic treatment. We recommend that you 

analyze these solutions in the following order: Diluent, Dilute Solution 1, Dilute Solution 2, 

Dilute Solution 3, Dilute Solution 3, Dilute Solution 2, Dilute Solution 1, Diluent. 

a)	 Compare the values of the duplicate measurements. Are you satisfied that your measurement 

precision is adequate? 

b)	 Compare the measured with the calculated [TAA] 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 analyze the serum control materials or test samples until you are satisfied that your 

system is performing properly! 

7)	 Once you have confirmed that your system is properly calibrated, analyze the serum control 

CS #2 (see protocol below). The target values for this materials is 28.1 ±1.0 μmol/L of sample. 

If your measured values are not close to this value, please review your sample preparation 

procedure and whether you followed exactly the same measurement protocol the solutions 

prepared from the solid control material as you used for these serum controls. If the protocols 

differ, please repeat from Step 6 using the proper protocol. If the proper protocol was used, your 

measurement system may not be suitable for MPA-preserved samples; please contact us at 301­

975-3120 or jbthomas@NIST.gov. 

Do not analyze the test samples until you are satisfied that your system is performing properly 

and is suitable for the analysis of MPA-preserved serum! 

Protocol for Analysis of the Serum Control Materials and Test Samples 

The serum control material and test samples are in sealed ampoules. They were prepared by adding 

equal volumes of 10% MPA 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 serum control material and test samples should be defrosted by warming at 20 °C for not more 

than 10 min otherwise some irreversible degradation may occur. 

Each serum 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
Participant #: Date: 

Vitamin C Round Robin 29 

NIST Micronutrient Measurement Quality Assurance Program 

Preparation and Validation of Ascorbic Acid Solid Control Material 

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
	

Please return before 12-Sep-2008 

MMQAP Fax: 301-977-0685 

100 Bureau Drive, Stop 8392 Email: david.duewer@nist.gov 

Gaithersburg, MD 20899-8392 

E5
 

 

 

 

 

 

 

 

 

 

 

Participant #: Date: 

Vitamin C Round Robin 29 

NIST Micronutrient Measurement Quality Assurance Program
 

Analysis of Control Materials 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 

μmol/L of Sample CS #2 Target: 28.1 ±1.0 μmol/L 

Serum Test Sample #15 μmol/L of Sample 

Serum Test Sample #73 μmol/L of Sample 

Serum Test Sample #90 μmol/L of Sample 

Serum Test Sample #111 μmol/L of Sample 

Were samples frozen upon receipt? Yes | No 

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

If “Other”, please describe: 

COMMENTS: 

Please return before 12-Sep-2008 

MMQAP Fax: 301-977-0685 

100 Bureau Drive, Stop 8392 Email: david.duewer@nist.gov 

Gaithersburg, MD 20899-8392 

E6
 

 

 

 

Participant #: ________ Date: _____________ 

Vitamin C Round Robin 29
 

NIST Micronutrients Measurement Quality Assurance Program
 

Packing List and Shipment Receipt Confirmation Form
 

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

Label Form
 

VitC #15 Liquid frozen (1:1 serum:10% MPA) 

VitC #73 Liquid frozen (1:1 serum:10% MPA) 

VitC #90 Liquid frozen (1:1 serum:10% MPA) 

VitC #111 Liquid frozen (1:1 serum:10% MPA) 

CS #2 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 the samples 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 of the vials intact? Yes | No 

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

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

4) Did the samples 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 

E7
 

 

Appendix F. Final Report for RR29 

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
November 25, 2008 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National lnatimte Df St:andarda and Technology 

Gaithersburg, Maryland 2089!}. 

Enclosed is the summary report of the results for Round Robin 29 (RR29) 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 an individualized summary of your 

laboratory's measurement performance. The robust median is used to estimate the consensus 

value for all samples, the "median absolute deviation from the median" (MADe) is used to 

estimate the expected standard deviation, and the coefficient of variation (CV) is defined as 

I 00 xMADe/median. 

RR 29 consisted of four test samples (#15, #73, #90, and #111), one serum control material 

(CS#2), and one solid control material for preparation of T AA control solutions. Details 

regarding the samples can be found in the enclosed report. 

If you have concerns regarding your iaboratory's perfonnance, 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 the first vitamin C round robin (RR30) of the 2009 M2

QAP will be shipped during 

the week of December 8, 2009. If you have questions or concerns 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 ov; fax: 301-977-0685. 

. -t..-t 

anice Brown Tho 

esearch Chemist 

7\.nalytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

Cc: L. C. Sander 

D.L. Duewer 

NISI 

F2
The NIST M2

QAP Vitamin C Round Robin 29 (RR29) report consists of 

Page “Individualized” Report 

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

ascorbic acid solid control sample, the serum control sample, and the four serum test 

samples. 

2 Graphical summary of your RR29 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR29 

samples and control/calibration solutions. 

Serum-based Samples. One serum control and four unknowns were distributed in RR29. 

CS#2 SRM 970 level 2, ampouled in mid-1998. 

S29:1 A “blank” stripped serum, ampouled in late 2001, previously distributed as sample S19:1 

(RR19, 9/03), S21:1 (RR21, 9/04), S23:1 (RR23, 9/05), and S26:1 (RR26, 3/07). 

S29:1 SRM 970 level 1, ampouled in mid-1998. 

S29:2 SRM 970 level 2, ampouled in mid-1998. 

S29:4 Serum 111, ampouled in 1989. It was used in some early experiments but was first
 

distributed in the current MMQAP as S25:3 (RR25, 9/06). 

Results. 

1)	 Nearly all participants who prepared the four 5% MPA control/calibration solutions (the three 

“Dilute Solutions” and the “Diluent”) did so correctly. 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 (≈0.58 OD), the calculated E1% #1”(≈560 

dL/g·cm). On the evidence of MPA density, one participant prepared the solutions in 0% MPA. 

2)	 The Measured = a+b*Gravimetric calibration parameters for the control/calibration solutions 

(columns 10 to 13 of the All Lab Report) indicate that the measurement systems for all participants 

are linear (R2

 close to 1 and RMS close to 0.0) and reasonably well calibrated (intercepts range from 

-1.2 to 1.5 and slopes range from 0.88 to 1.04). 

3)	 The Measured = p+q*Median regression parameters for samples S29:1 to S29:4 (columns 23 to 26 of 

the All Lab Report) mostly confirm the linearity of the measurement systems (R2

 close to 1 and RMS 

close to 0.0). As in RR28, there appears to be no correlation between regression intercepts and 

slopes and those for gravimetric calibration, again implying the existence of serum matrix effects. 

4)	 There is no evidence of sample degradation in either of the SRM 970 materials. 

5) There is little evidence for any “attraction to the known-value” in 

the analysis of the control material. However, comparison of the 

SRM 970-II material analyzed as CS#2 and as S29:3 (see Youden 

plot to the right) provides direct evidence that most of the 

observed among-participant differences in reported value result 

from systematic biases among the measurement systems. 

SRM 970-II as S29:3 

32 

30 

28 

24 26 28 30 32 

SRM 970-II as CS#2 

26 

24 

F3
Appendix G. “All-Lab Report” for RR29 

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 Acid 

"Round Robin" 29 - September 2008 

Control / Calibration Samples MPA Dilute Solution 1 

G2

Density 

Lab Date Dil:1 Dil:2 Dil:3 Dil:1 Dil:2 Dil:3 MPA Inter Slope R2 RMS g/mL λmax Amax E1% CS#2 S29:1 S29:1 S29:2 S

VC-MA 11/08/08 58.2 28.9 14.8 59.9 30.8 15.5 0.0 0.34 1.03 1.000 0.6 1.036 243. 0.5670 553.2 27.2 0.0 0.0 8.3 

VC-MB 20/06/08 59.1 29.4 14.6 60.7 30.5 14.2 0.0 -0.27 1.03 1.000 0.6 1.029 244. 0.5640 542.1 26.8 0.0 0.0 8.0 

VC-MC 20/06/08 56.2 28.6 14.3 58.2 28.8 13.4 0.0 -0.73 1.04 0.999 0.8 1.029 243. 0.5460 551.8 29.7 0.0 0.0 8.6 

VC-ME 19/09/08 57.3 28.8 14.2 57.6 31.2 14.6 0.0 0.58 1.01 0.998 1.3 1.031 243. 0.5955 590.3 30.0 4.2 4.2 9.8 

VC-MG 21/08/08 61.1 31.7 17.0 62.2 31.2 14.8 0.0 -1.16 1.03 0.998 1.4 1.029 243.8 0.5980 555.3 28.1 0.0 0.0 6.9 

VC-MH 19/06/08 61.3 30.4 15.3 62.4 30.7 15.4 0.0 -0.13 1.02 1.000 0.2 1.032 244.1 0.6130 567.9 27.8 0.3 0.3 8.1 

VC-MI 10/09/08 57.1 28.4 13.9 53.1 27.9 14.5 0.0 0.91 0.92 0.999 1.0 1.032 28.5 0.0 0.0 8.7 

VC-MJ 22/08/08 59.0 28.4 14.8 58.1 28.7 15.0 0.0 0.37 0.98 1.000 0.5 1.027 254a 0.356a 342.3a 32.5 4.9 4.9 11.7 

VC-MK 12/06/08 60.4 30.6 14.9 54.7 28.5 15.4 1.0 1.53 0.88 0.999 0.7 0.999 244. 0.5865 551.0 27.0 5.7 5.7 13.9 

VC-MN 08/09/08 60.4 29.8 14.9 60.9 31.0 15.3 0.8 0.77 1.00 1.000 0.4 1.038 243.7 0.5600 526.4 30.7 7.2 7.2 16.4 

VC-MP 10/09/08 28.2 0.0 0.0 9.0 

VC-MS 25/06/08 27.5 0.0 0.0 9.0 

VC-MU 27/08/08 26.1 0.6 0.6 7.4 

10 10 10 10 10 10 10 10 8 8 8 13 13 13 13 

59.0 29.5 14.9 58.8 29.9 14.8 0.2 1.028 243.6 0.5788 554.8 28.5 1.8 1.8 9.7 

1.8 1.1 0.8 3.1 1.3 0.7 0.4 0.011 0.5 0.0229 18.6 1.8 2.7 2.7 2.7 

56.2 28.39 13.9 53.1 27.87 13.4 0.0 0.999 243.0 0.5460 526.4 26.1 0.0 0.0 6.9 

57.5 28.69 14.4 57.8 28.74 14.6 0.0 1.029 243.0 0.5630 548.8 27.2 0.0 0.0 8.1 

59.1 29.12 14.8 59.1 30.55 14.9 0.0 1.030 243.8 0.5768 552.5 28.1 0.0 0.0 8.7 

60.4 30.24 14.9 60.9 30.92 15.3 0.0 1.032 244.0 0.5961 558.5 29.7 4.2 4.2 9.8 

61.3 31.71 17.0 62.4 31.25 15.5 1.0 1.038 244.1 0.6130 590.3 32.5 7.2 7.2 16.4 

2.3 1.0 0.4 2.6 1.0 0.6 0.0 0.0 0.4 0.0263 9.8 1.6 0.0 0.0 1.0 

4 3 3 4 3 4 0.25 0.17 4.6 1.8 6 12 

Grav, μmol/L Measured, μmol/L Measured = a + b*Grav Spectrophotometry Measured, μmol/L 

N N 

Average Average 

SD SD 

Max 

Min Min 

%25 %25 

MADe eSD 

CV CV 

Median Median 

%75 %75 

Max 

All Lab Report 
Appendix H. Representative “Individualized Report” for RR29 

Each participant in RR29 received an “Individualized Report” reflecting their reported 

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

“VC-MA”. 

H1
 

 Set 1 of 15 

Vitamin C "Round Robin" 29 Report: Participant VC-MA
 

MPA Dilute Solution 1 Control/Calibration Solutions 

Density Spectrophotometry Ymeas = Inter + Slope* Xgrav 

g/mL 

1.031 

1.039 

1.033 

1.032 

1.035 

1.037 

λmax 

244.0 

242.0 

244.0 

242.0 

243.0 

243.0 

Amax E1% 

0.568 586.7 

0.555 557.4 

0.573 554.3 

0.561 557.2 

0.572 562.2 

0.567 553.2 

Inter Slope R2 SEE 

0.2 1.13 1.000 0.41 

0.8 0.95 0.999 0.92 

0.3 1.00 1.000 0.31 

-0.1 0.99 1.000 0.14 

0.7 1.03 0.999 0.99 

0.3 1.03 1.000 0.64 

Date RR Method 

03/09/06 24 HPLC-EC 

08/28/06 25 HPLC-EC 

03/20/07 26 HPLC-EC 

10/05/07 27 HPLC-EC 

03/04/08 28 HPLC-EC 

08/11/08 29 HPLC-EC 

Mean 1.035 243.0 0.57 561.8 0.57 

SD 0.003 0.9 0.01 12.6 0.34 

CV 0.28 0.37 1.2 2.2 

[TAA] mmol/Lsample 

4 0.0 0.0 0.0 

6 8.5 0.2 0.3 

5 27.4 0.3 1.8 

Date RR Sample 

03/08/05 22 CS#2 

10/17/05 23 CS#2 

03/09/06 24 CS#2 

08/28/06 25 CS#2 

10/05/07 27 CS#2 

08/11/08 29 CS#2 

11/18/02 16 S16:2 

11/13/03 19 S19:1 

09/13/04 21 S21:1 

10/17/05 23 S23:1 

03/20/07 26 S26:1 

08/11/08 29 S29:1 

11/18/02 16 S16:1 

11/13/03 19 S19:4 

02/23/04 20 S20:3 

10/17/05 23 S23:4 

08/28/06 25 S25:1 

08/11/08 29 S29:2 

03/20/03 18 S18:3 

02/23/04 20 S20:4 

03/08/05 22 S22:4 

08/28/06 25 S25:2 

08/11/08 29 S29:3 

Rep1 

29.0 

29.4 

29.2 

27.2 

28.1 

27.2 

Rep2 

29.0 

30.5 

29.1 

28.1 

27.4 

27.2 

Fadj 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

Mean 

29.0 

30.0 

29.2 

27.6 

27.7 

27.2 

SDdup 

0.0 

0.8 

0.1 

0.6 

0.5 

0.0 

N Mean SDrepeat SDreprod 

6 28.4 0.5 1.1 

0.0 

na 

na 

0.0 

0.0 

0.0 

8.8 

7.8 

8.3 

8.6 

8.7 

8.3 

28.8 

25.9 

29.4 

27.6 

25.6 

0.1 

na 

na 

0.0 

0.0 

0.0 

8.8 

8.6 

8.1 

8.8 

8.5 

8.4 

29.2 

25.2 

29.4 

27.4 

25.7 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

0.0 

0.0 

0.0 

0.0 

8.8 

8.2 

8.2 

8.7 

8.6 

8.3 

29.0 

25.5 

29.4 

27.5 

25.6 

0.0 

0.0 

0.0 

0.0 

0.0 

0.5 

0.1 

0.1 

0.2 

0.1 

0.3 

0.5 

0.0 

0.1 

0.1 

08/28/06 25 S25:3 2 12.7 0.2 0.5 

08/11/08 29 S29:4 

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 

12.3 

12.8 

12.4 

13.3 

1.0 

1.0 

12.4 

13.0 

0.1 

0.3 

Individualized Report Page 1 / 2 

H2
 

NIST, RR 22

H3

 Set 1 of 15 

Vitamin C "Round Robin" 29 Report: Participant VC-MA 

Total Ascorbic Acid, μmol/mL 

[Total Ascorbic Acid], μmol/L 

S11:1S12:1 S13:1S14:3 S15:1 S16:1 S19:4 S20:3 S23:4 Apparent Precision, SD S25:1S29:2S11:2 S12:2S13:2S14:4S15:2S18:3S20:4S22:4S25:2S29:3S25:3S29:4 

Your [Total Ascorbic Acid], μmol/L 

Median [Total Ascorbic Acid], μmol/L 

Concordance, SD 

3rd Quartile (75%) You, this RR Median (50%) You, pat RRs Others, this RR 1st Quartile (25%) 

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

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

Sample Comments 

S29:1 VitC #15 (not displayed), serum blank previously distributed in RRs 16, 19, 21, 23, and 26 

S29:2 VitC #73, previously distributed in RRs 11, 12, 13, 14, 15, 16, 19, 20, 23, and 25 

S29:3 VitC #90, previously distributed in RRs 11, 12, 13, 14, 15, 18, 20, 22, and 25 

S29:4 VitC #111, previously distributed in RR 25 

Individualized Report Page 2 / 2