NISTIR 7880-18 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2003 

Comparability Studies 

Results for Round Robin LIV 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 19 Ascorbic Acid in Human Serum 

David L. Duewer 

Katherine E. Sharpless 

Jeanice B. Thomas 

 

 

 

 

NISTIR 7880-18
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Summer 2003 

Comparability Studies 

Results for Round Robin LIV 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 19 Ascorbic Acid in Human Serum 

David L. Duewer 

Katherine E. Sharpless 

Jeanice B. Thomas 

Chemical Sciences Division 

Materials Measurement Laboratory 

June 2013 

 U.S. Department of Commerce 

Cameron F. Kerry, 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 2003 MMQAP measurement comparability improvement studies: 1) Round Robin LIV FatSoluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 19 Total Ascorbic Acid in 

Human Serum. The materials for both studies were shipped to participants in March 2003; 

participants were requested to provide their measurement results by September 19, 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 LIV: Fat-Soluble Vitamins and Carotenoids in Human Serum ............................ 1
 

Round Robin 19: Vitamin C in Human Serum............................................................................... 2
 

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

Appendix A. Shipping Package Inserts for RR54........................................................................ A1
 

Appendix B. Final Report for RR54 ..............................................................................................B1
 

Appendix C. “All-Lab Report” for RR54 ......................................................................................C1
 

Appendix D. Representative “Individualized Report” for RR54 ............................................... D1
 

Appendix E. Shipping Package Inserts for RR19 ......................................................................... E1
 

Appendix F. Final Report for RR19............................................................................................... F1
 

Appendix G. “All-Lab Report” for RR19..................................................................................... G1
 

Appendix H. Representative “Individualized Report” for RR19............................................... 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 LIV: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

LIV comparability study (hereafter referred to as RR54) 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 

March 2003. 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 RR54 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 19: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 19 comparability study 

(hereafter referred to as RR19) received four frozen serum test samples and a solid ascorbic acid 

control material for analysis. Unless multiple vials were previously requested, participants received 

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

2003. 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 RR19 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 RR54 

The following three items were included in each package shipped to an RR54 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
March 26, 2003 

. Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and ·Technology 

Gaithersburg, Maryland 20899-0001 

Enclosed are the samples (Sera 294 - 298) for the second fat-soluble vitamins and carotenoids in serum 

round robin study (Round Robin LIV) for the 2003 NIST Micronutrients Measurement Quality Assurance 

Program. You will find one vial of each of two liquid-frozen and three 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 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 19, 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 mid-October. 

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 296 and 298. 

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); a-tocopherol, 75.8 at 292 nm (ethanol); ytocopherol, 91.4 at 298 nm (ethanol); a-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 LIV 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 qf5ies to the above address. 

·n=ly:1u~ iJ11kw 

ice Brown Thomas 

Research Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Enclosures 

NISI 

A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LIV 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 294 295 296 297 298 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 analytes? 

* we prefer μg/mL 

Were sera {296,297,298} frozen when received? Yes | No 

Comments: 

Mail: M2QAP 

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

Gaithersburg, MD 20899-8392 19-Sep-2003 Email: David.Duewer@NIST.gov 

A3
 

 

 

 

Participant #: ________ Date: _____________ 

Fat-Soluble Vitamins Round Robin LIV 

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? 

#294 Lyophilized Yes (1 ml H2O) 

#295 Lyophilized Yes (1 ml H2O) 

#296 Liquid frozen No 

#297 Liquid frozen No 

#298 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 {296,297,298} 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 {296,297,298} 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 RR54 

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
October 15, 2003 

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 LIV (RR 54) for fat-soluble vitamins and 

carotenoids. 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 comparabilities relative to the NIST assigned values. 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 54 are provided in the comparability summary (Score 

Card) on page 6 of the All Lab Report. Laboratory comparability is summarized as follows: results rated 1 

to 3 are within 1 to 3 standard deviation(s) of the assigned value, respectively; those rated 4 are >3 

standard deviations from the assigned value. 

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

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

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

Samples for the first round robin exercise (RR55) for the 2004 QA program will be distributed during the 

week of November 17, 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. 

Please mark your calendars. Our next QA workshop will be held in conjunction with Experimental 

Biology '04 on Wednesday, April 21, 2004 in Washington, DC. A preliminary workshop agenda can be 

found at: www.asns.org. We will send you more information about the workshop as our plans are finalized. 

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. 

Sincerely, , ~ {} 

Ji~~ ()-j~a,1 I J~amce Brown Thomas 

''-'esearch Chemist 

Analytical Chemistry Division 

Chemical Science and Technology Laboratory 

Cc: D.L. Duewer 

L.C. Sander 

S.A. Wise 

Enclosures 

NlSI 

B2
 

 

The NIST M2QAP Round Robin LIV (RR54) report consists of: 

Page 

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

5a A list of results for the four analytes reported by only one laboratory. 

5b A legend for the above two lists. 

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

Page “Individualized” Report 

1 

2 to 

n 

n+1 

Samples.

Serum 

294 

295 

296 

297 

298 

Results 

“All Lab” Report 

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

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

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

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

 The five sera below were distributed in RR54. 

Description	 Prior Distributions 

Lyophilized, low-carotenoid pool augmented 

with trans-retinol; retinyl palmitate; α-, γ-, and 

δ-tocopherol, trans-α- and β-carotene, and 

trans-lycopene; serum pool was prepared in 

1995. 

Lyophilized, native, single donor serum 

prepared in 1999. The same material was used 

to prepare Serum 296. 

Fresh-frozen, native, single donor serum 

prepared in 1999. The same material was used 

to prepare Serum 295. 

The same fresh-frozen blended serum as 

Serum 298, augmented with ≈0.3 μg/mL 

trans-retinol; serum pool was prepared in 

2002. 

The same fresh-frozen blended serum as 

Serum 297, augmented wit`h ≈0.3 μg/mL 13-

cis-retinol; serum pool was prepared in 2002. 

Serum 203 RR33 (Mar-95)
 

Serum 273 RR16 (Mar-01)
 

Serum 266 RR48 (Sep-00) 

Serum 277 RR50 (Sep-01) 

Serum 282 RR51 (Mar-02) 

Serum 271 RR49 (Mar-01) 

Serum 275 RR50 (Sep-01) 

Serum 279 RR51 (Mar-02) 

Serum 285 RR52 (Sep-02) 

Serum 286 RR52 (Sep-02) 

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

measurands in the lyophilized Serum 294 after 8 years; however, there was an apparent decline in 

retinyl palmitate between the first distribution in 1995 and the second in 2001. Since this serum was 

prepared using an experimental augmentation protocol, this may reflect a real change in level. Given 

that the 2003 results are nearly the same as those of 2001, the apparent decline could also be a 

B3
 

measurement artifact. 

There has been no significant change in the median level or variability for any measurand in the 

fresh-frozen Serum 296 after two years nor in Sera 297 and 298 after 1 year. 

2)	 Matrix (Lyophilized Vs Fresh-Frozen) Differences. Sera 295 and 296 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 295 should be ≈ 95% of those in 

Serum 296. The observed average ±SD over all measurands with 10 or more quantitative 

measurements is 94.0 ±1.2%. If any of your Sera 295/296 ratios are much different than 0.95, you 

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

3)	 Total Retinol and trans-retinol. Sera 297 and 298 are identical except that Serum 297 was 

augmented with about 0.3 μg/mL trans-retinol and Serum 297 was augmented with the same 

concentration of 13-cis-retinol. This is a repeat of last year’s evaluation of “total retinol” and “transretinol” reporting. At that time, there were three different types of anomalous reports: (1) total 

values reported as trans, (2) trans values reported as total, and (3) something about half-way inbetween total and trans reported as total retinol. 

The good news: there were no type (1) or (2) anomalies reported in this exercise. All participants 

who reported trans-retinol reported the expected values for both the trans- and cis-spiked sera. 

The less good news: there are still type (3) anomalies. Several participants reported a “Total retinol” 

value for the cis-retinol spiked Serum 298 that is roughly half-way between the value expected for 

trans- and Total retinol. We believe that this results from quantitation by peak height in combination 

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

quantitate by peak height and your value for total retinol for Serum 298 was more than 0.05 μg/mL 

lower than that for Serum 297, you should consider using peak area to quantify total retinol. 

B4
Appendix C. “All-Lab Report” for RR54 

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

consensus summary results of the study. 

C1
 Round Robin LIV Laboratory Results 

All Values in μg/mL 

Total Retinol trans-Retinol Retinyl Palmitate α-Tocopherol 

Lab 294 295 296 297 298 

C2

FSV-BA 1.263 0.454 0.500 0.671 0.582 

FSV-BB 1.169 0.439 0.430 0.583 0.561 

FSV-BD 1.252 0.452 0.467 0.641 0.621 

FSV-BE 1.370 0.470 0.540 0.680 0.600 

FSV-BF 0.970 0.410 0.410 0.580 0.460 

FSV-BG 1.274 0.453 0.492 0.651 0.622 

FSV-BH 1.255 0.478 0.493 0.700 0.474 

FSV-BI 1.287 0.449 0.472 0.638 0.611 

FSV-BJ 1.233 0.432 0.450 0.612 0.600 

FSV-BK 1.250 0.410 0.420 0.560 0.530 

FSV-BL - 0.400 0.460 0.600 0.600 

FSV-BM 1.218 0.489 0.509 0.651 0.673 

FSV-BN 1.260 0.436 0.422 0.639 0.624 

FSV-BO 1.120 0.415 0.444 0.599 0.570 

FSV-BP 1.191 0.455 0.475 0.613 0.607 

FSV-BQ 1.320 0.458 0.494 0.642 0.554 

FSV-BR ≥1.180 ≥0.440 ≥0.460 ≥0.610 ≥0.350

FSV-BS 1.261 0.362 0.417 0.616 0.579 

FSV-BT 0.978 0.434 0.515 0.728 0.784 

FSV-BU 1.154 0.429 0.461 0.625 0.574 

FSV-BV 1.351 0.493 0.520 0.681 0.517 

FSV-BW 1.250 0.440 0.470 0.625 0.618 

FSV-BX 1.190 0.424 0.457 0.627 0.608 

FSV-CB 1.057 0.421 0.399 0.552 0.521 

FSV-CC 1.360 0.460 0.470 0.630 0.590 

FSV-CD 1.278 0.453 0.465 0.631 0.623 

FSV-CE 1.269 0.427 0.472 0.586 0.617 

FSV-CF 1.125 0.433 0.474 0.648 0.627 

FSV-CG 1.204 0.493 0.467 0.605 0.572 

FSV-CI 1.120 0.420 0.440 0.590 0.470 

FSV-CP 

FSV-CS 1.310 0.460 0.490 0.690 0.670 

FSV-CT 

FSV-CZ 1.240 0.410 0.440 0.580 0.580 

FSV-DA 1.278 0.437 0.462 0.617 0.607 

FSV-DF 1.289 0.445 0.489 0.633 0.612 

FSV-DI 1.410 0.483 0.510 0.713 0.673 

FSV-ET 1.240 0.430 0.430 0.560 0.560 

294 295 296 297 298 

1.180 0.440 0.460 0.610 0.350 

1.340 0.450 0.470 0.630 0.420 

1.289 0.445 0.489 0.633 0.407 

294 295 296 297 298 

0.047 0.050 0.055 0.019 0.016 

0.045 0.046 0.049 0.012 0.013 

0.031 0.049 0.061 0.031 0.033 

0.064 0.045 0.058 0.023 0.018 

0.050 nq nq nq nq 

0.042 0.042 0.038 0.012 0.015 

0.064 0.065 0.073 0.021 0.020 

0.072 0.056 0.067 0.017 0.018 

0.110 0.070 0.040 nq nq 

0.061 0.055 0.058 0.014 0.014 

0.056 0.057 0.055 0.023 0.023 

294 295 296 297 298 

17.21 6.76 7.27 2.84 2.83 

17.05 6.68 6.70 2.76 2.69 

18.20 8.00 7.50 3.00 3.20 

18.00 7.20 7.80 3.30 3.30 

12.70 7.10 7.30 2.60 2.60 

17.12 7.03 7.63 3.03 2.98 

18.05 7.44 7.50 3.10 3.06 

17.54 7.09 7.22 2.94 2.92 

17.66 6.70 7.00 2.77 2.76 

15.55 5.90 6.05 3.20 3.10 

- 7.32 8.18 3.45 3.45 

18.00 7.30 7.80 4.00 4.20 

14.83 5.91 5.55 2.61 2.57 

16.45 6.55 7.06 2.80 2.84 

16.75 6.75 6.66 3.06 3.070 

16.80 6.50 7.20 2.90 2.70 

17.50 7.10 7.30 2.89 3.11 

18.91 6.01 7.22 2.90 2.81 

17.64 6.54 7.11 2.58 2.50 

16.54 6.69 6.98 2.79 3.11 

16.66 6.58 6.98 2.78 2.75 

16.52 6.63 7.15 2.93 2.90 

14.99 5.97 6.43 2.55 2.59 

17.42 6.65 7.23 2.83 2.68 

16.89 7.11 7.26 2.90 2.95 

17.51 7.34 8.01 2.66 2.62 

17.50 7.70 8.50 3.90 3.90 

14.70 6.56 6.82 2.80 2.75 

18.40 7.10 7.10 3.10 2.80 

14.14 6.40 6.87 3.14 3.20 

16.08 6.79 7.08 2.98 2.89 

15.60 5.50 5.90 2.30 2.40 

16.72 6.80 7.22 2.85 2.86 

21.59 8.19 8.34 3.26 3.21 

17.10 6.70 6.70 2.70 2.80 

294 

1.2

1.1

1.2

1.3

1.2

1.4

1.2

1.2

0.9

0.6

1.3

1.2

1.1

1.1

1.3

1.2

1.2

1.0

1.4

1.2

1.3

1.1

N 34 35 35 35 35 3 3 3 3 3 11 10 10 9 9 34 35 35 35 35 2

Min 0.970 0.362 0.399 0.552 0.460 1.180 0.440 0.460 0.610 0.350 0.031 0.042 0.038 0.012 0.013 12.70 5.50 5.55 2.30 2.40 0.6

Median 1.251 0.439 0.467 0.627 0.600 1.289 0.445 0.470 0.630 0.407 0.056 0.052 0.057 0.019 0.018 17.07 6.75 7.20 2.90 2.86 1.2

Max 1.410 0.493 0.540 0.728 0.784 1.340 0.450 0.489 0.633 0.420 0.110 0.070 0.073 0.031 0.033 21.59 8.19 8.50 4.00 4.20 1.4

SD 0.065 0.023 0.036 0.037 0.040 0.013 0.008 0.007 0.007 0.004 0.85 0.41 0.36 0.23 0.28 0.1

CV 5 5 8 6 7 24 15 13 35 21 5 6 5 8 10 

Npast 43 41 38 36 39 11 8 8 5 4 12 13 13 9 9 46 47 44 38 39 2

Medianpast 1.275 0.448 0.467 0.621 0.580 1.180 0.437 0.451 0.608 0.389 0.096 0.051 0.054 0.013 0.014 16.96 6.76 7.13 2.95 2.94 1.2

SDpast 0.127 0.045 0.045 0.063 0.057 0.059 0.037 0.033 0.030 0.044 0.030 0.012 0.014 0.005 0.004 1.25 0.62 0.63 0.24 0.26 0.1

NISTa 1.298 0.479 0.480 0.649 0.624 1.273 0.479 0.480 0.649 0.373 16.61 7.11 6.92 2.79 2.74 1.2

NISTb 1.278 0.477 0.483 0.667 0.654 1.217 0.470 0.483 0.662 0.369 17.31 6.93 7.10 2.78 2.80 1.0

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

Mean 1.288 0.478 0.482 0.659 0.639 1.245 0.474 0.481 0.657 0.371 16.96 7.02 7.01 2.77 2.77 1.1

Srep 0.036 0.021 0.008 0.008 0.017 0.037 0.021 0.008 0.007 0.006 0.36 0.26 0.03 0.05 0.09 0.0

Shet 0.032 0.026 0.006 0.007 0.019 0.039 0.026 0.006 0.008 0.009 0.39 0.39 0.21 0.06 0.08 0.0

Sanl 0.014 0.001 0.002 0.014 0.021 0.039 0.006 0.002 0.011 0.003 0.49 0.13 0.13 0.02 0.04 0.1

SNIST 0.050 0.033 0.010 0.018 0.033 0.066 0.033 0.010 0.015 0.011 0.73 0.49 0.25 0.08 0.13 0.1

NAV 1.269 0.459 0.474 0.643 0.619 1.267 0.460 0.476 0.643 0.389 0.056 0.052 0.057 0.019 0.018 17.02 6.89 7.10 2.83 2.81 1.1

NAU 0.099 0.045 0.039 0.055 0.055 0.103 0.042 0.039 0.053 0.045 0.017 0.017 0.017 0.011 0.011 1.33 0.60 0.61 0.41 0.40 0.1

All Lab R eport 
 

 

Round Robin LIV Laboratory Results 

All Values in μg/mL 

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

Lab 294 295 296 297 298 

C3

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
 2.522 0.112 0.124 0.053 0.064 

FSV-BO 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 1.962 0.140 0.210 0.150 0.098 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-BX 

FSV-CB 

FSV-CC 

FSV-CD 

FSV-CE 

FSV-CF 

FSV-CG 1.174 0.080 0.076 0.038 0.038 

FSV-CI 

FSV-CP 

FSV-CS 

FSV-CT 

FSV-CZ 

FSV-DA 3.890 0.139 0.126 0.063 0.064 

FSV-DF 

FSV-DI 5.480 0.211 0.200 0.077 0.078 

FSV-ET 

294 295 296 297 298 

0.054 0.326 0.350 0.048 0.047 

0.054 0.308 0.309 0.044 0.044 

0.045 0.315 0.327 0.048 0.047 

0.061 0.377 0.370 0.061 0.046 

0.054 0.360 0.401 0.055 0.055 

0.054 0.360 0.364 0.050 0.048 

0.059 0.343 0.354 0.049 0.049 

0.049 0.320 0.344 0.047 0.043 

0.059 0.308 0.288 0.053 0.049 

0.052 0.374 0.398 0.056 0.065 

0.055 0.318 0.318 0.057 0.060 

≥0.033 ≥0.288 ≥0.325 ≥0.035 ≥0.033

0.053 0.323 0.429 0.053 0.054 

0.068 0.282 0.298 0.060 0.057 

0.054 0.342 0.372 0.053 0.052 

0.051 0.307 0.340 0.045 0.043 

≥0.063 ≥0.286 ≥0.346 ≥0.053 ≥0.051

0.076 0.359 0.356 0.059 0.050 

0.065 0.361 0.353 0.042 0.042 

0.052 0.337 0.383 0.049 0.057 

0.055 0.328 0.361 0.049 0.051 

≥0.058 ≥0.294 ≥0.340 ≥0.040 ≥0.049

0.047 0.280 0.304 0.044 0.046 

0.050 0.330 0.350 0.050 0.050 

0.057 0.305 0.318 0.054 0.051 

0.080 0.300 0.320 0.050 0.060 

0.071 0.358 0.384 0.059 0.055 

≥0.047 ≥0.413 ≥0.408 ≥0.043 ≥0.043

0.060 0.360 0.370 0.050 0.060 

294 295 296 297 298 

0.051 0.310 0.334 0.047 0.047 

0.052 0.293 0.292 0.043 0.043 

0.054 0.340 0.345 0.050 0.048 

0.055 0.282 0.266 0.048 0.047 

0.033 0.288 0.325 0.035 0.033 

0.050 0.323 0.396 0.050 0.050 

0.063 0.286 0.346 0.053 0.051 

0.051 0.306 0.335 0.047 0.048 

0.06 0.29 0.34 0.04 0.05 

0.046 0.302 0.322 0.047 0.045 

0.065 0.328 0.357 0.054 0.051 

0.047 0.413 0.408 0.043 0.043 

294 295 296 297 298 

0.003 0.017 0.016 0.001 0.001 

0.002 0.016 0.017 0.001 0.001 

nq 0.020 0.018 nq nq 

nd nd 0.025 0.008 0.005 

0.004 0.024 0.027 0.003 0.004 

nq 0.022 0.025 nq nq 

0.01 0.03 0.03 0.00 0.00 

0.006 0.030 0.027 0.005 0.004 

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

N 5 5 5 5 5 25 25 25 25 25 12 12 12 12 12 5 7 8 6 6 

Min 1.174 0.080 0.076 0.038 0.038 0.045 0.280 0.288 0.042 0.042 0.033 0.282 0.266 0.035 0.033 0.002 0.016 0.016 0.001 0.001 0

Median 2.522 0.139 0.126 0.063 0.064 0.054 0.328 0.353 0.050 0.050 0.052 0.304 0.338 0.047 0.048 0.004 0.022 0.025 0.003 0.004 0

Max 5.480 0.211 0.210 0.150 0.098 0.080 0.377 0.429 0.061 0.065 0.065 0.413 0.408 0.054 0.051 0.006 0.031 0.032 0.008 0.005 0

SD 1.431 0.021 0.056 0.018 0.010 0.006 0.038 0.037 0.005 0.006 0.005 0.024 0.018 0.005 0.004 0.001 0.006 0.007 0.002 0.002 0

CV 57 15 45 28 16 11 12 11 10 12 9 8 5 11 7 32 30 28 69 44 

Npast 8 6 6 5 5 33 31 31 28 28 13 15 14 12 12 6 10 10 6 6 

Medianpast 3.140 0.145 0.138 0.067 0.065 0.056 0.321 0.347 0.052 0.049 0.053 0.294 0.313 0.048 0.048 0.010 0.023 0.023 0.003 0.003 0

SDpast 0.549 0.115 0.087 0.052 0.022 0.014 0.050 0.038 0.009 0.008 0.008 0.030 0.025 0.006 0.005 0.009 0.008 0.006 0.002 0.002 0

NISTa 0.054 0.340 0.311 ≥ 0.044 ≥ 0.042 0.049 0.283 0.275 0.044 0.042 0.005 0.057 0.036 ≤ 0.005 ≤ 0.005
 

NISTb
 3.114 0.103 0.109 0.033 0.037 0.058 0.339 0.355 0.045 0.048 0.054 0.315 0.330 0.045 0.046 0.008 0.024 0.025 nq nq 0

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

Mean 3.114 0.103 0.109 0.034 0.037 0.056 0.339 0.333 0.045 0.045 0.051 0.299 0.303 0.045 0.044 0.007 0.040 0.030 0

Srep 0.036 0.009 0.004 0.012 0.007 0.006 0.007 0.006 0.002 0.003 0.003 0.011 0.011 0.002 0.002 0.003 0.006 0.008 0

Shet 0.043 0.005 0.007 0.003 0.002 0.002 0.019 0.008 0.003 0.002 0.001 0.004 0.012 0.003 0.001 0.002 0.016 0.006 0

Sanl 0.002 0.000 0.031 0.001 0.004 0.004 0.023 0.039 0.001 0.003 0.002 0.023 0.008 

SNIST 0.056 0.010 0.008 0.012 0.007 0.007 0.020 0.032 0.003 0.006 0.005 0.026 0.042 0.003 0.004 0.003 0.029 0.012 0

NAV 2.818 0.121 0.118 0.048 0.051 0.055 0.334 0.343 0.047 0.048 0.051 0.301 0.320 0.046 0.046 0.005 0.031 0.028 0

NAU 1.491 0.038 0.058 0.028 0.027 0.011 0.048 0.052 0.011 0.012 0.009 0.033 0.049 0.009 0.009 0.004 0.032 0.013 0

All Lab R eport 
 Round Robin LIV Laboratory Results 

All Values in μg/mL 

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

Lab 294 295 296 297 298 

C4

FSV-BA
 

FSV-BB
 0.183 0.299 0.287 0.162 0.163 

FSV-BD 

FSV-BE 

FSV-BF 0.231 0.352 0.354 0.209 0.185 

FSV-BG 0.190 0.358 0.399 0.196 0.194 

FSV-BH 0.194 0.344 0.349 0.187 0.181 

FSV-BI 0.178 0.278 0.291 0.144 0.154 

FSV-BJ 0.165 0.294 0.313 0.163 0.158 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.183 0.313 0.302 0.184 0.179 

FSV-BO 0.258 0.425 0.426 0.251 0.223 

FSV-BP 0.232 0.386 0.347 0.254 0.250 

FSV-BQ 

FSV-BR 

FSV-BS 0.202 0.330 0.366 0.198 0.195 

FSV-BT 0.242 0.383 0.490 0.259 0.253 

FSV-BU 0.180 0.284 0.305 0.164 0.163 

FSV-BV 0.234 0.419 0.455 0.223 0.221 

FSV-BW 0.178 0.321 0.347 0.172 0.172 

FSV-BX 

FSV-CB 0.161 0.262 0.279 0.152 0.149 

FSV-CC 

FSV-CD 0.192 0.423 0.421 0.156 0.169 

FSV-CE 

FSV-CF 

FSV-CG 0.196 0.344 0.380 0.193 0.197 

FSV-CI 

FSV-CP 0.119 0.193 0.210 0.108 0.112 

FSV-CS 0.190 0.360 0.380 0.210 0.200 

FSV-CT 0.277 0.392 0.420 0.241 0.228 

FSV-CZ 

FSV-DA 0.215 0.366 0.395 0.197 0.203 

FSV-DF 

FSV-DI 

FSV-ET 

294 295 296 297 298 

0.104 0.178 0.192 0.094 0.095 

0.095 0.134 0.141 0.074 0.076 

0.117 0.230 0.252 0.117 0.113 

0.101 0.169 0.165 0.098 0.100 

0.094 0.151 0.193 0.099 0.096 

0.092 0.129 0.169 0.086 0.082 

0.100 0.182 0.202 0.101 0.102 

0.113 0.189 0.207 0.102 0.104 

0.156 0.282 0.284 0.148 0.143 

294 295 296 297 298 

0.061 0.058 0.061 0.021 0.020 

0.054 0.048 0.048 0.018 0.018 

0.043 0.039 0.042 0.016 0.013 

0.056 0.051 0.059 0.020 0.025 

0.080 0.078 0.080 0.028 0.028 

0.063 0.056 0.058 0.020 0.020 

0.056 0.053 0.052 0.020 0.018 

0.055 0.049 0.048 0.017 0.018 

0.052 0.049 0.051 0.017 0.017 

0.046 0.058 0.061 0.019 0.019 

0.041 0.045 0.051 0.017 0.015 

0.054 0.046 0.063 0.025 0.023 

0.060 0.052 0.054 0.026 0.026 

0.037 0.034 0.037 0.011 0.011 

0.050 0.042 0.043 0.010 0.013 

0.048 0.046 0.051 0.017 0.018 

0.016 0.055 0.062 0.023 0.024 

0.051 0.062 0.064 0.031 0.033 

0.054 0.053 0.056 0.021 0.020 

0.040 0.037 0.040 0.012 0.012 

0.047 0.051 0.054 0.019 0.018 

0.045 0.037 0.039 0.014 0.013 

0.066 0.062 0.066 0.021 0.023 

294 295 296 297 298 

0.030 0.021 0.021 0.010 0.010 

0.028 0.021 nd 0.009 0.009 

0.038 0.038 0.052 0.023 0.023 

0.030 0.023 0.025 0.011 0.011 

294 

0.068 

0.054 

0.064 

0.084 

0.086 

0.070 

0.049 

0.077 

0.072 

0.060 

0.057 

0.059 

0.068 

0.060 

0.090 

N 21 21 21 21 21 9 9 9 9 9 23 23 23 23 23 4 4 3 4 4 15 

Min 0.119 0.193 0.210 0.108 0.112 0.092 0.129 0.141 0.074 0.076 0.016 0.034 0.037 0.010 0.011 0.028 0.021 0.021 0.009 0.009 0.049 

Median 0.192 0.344 0.354 0.193 0.185 0.101 0.178 0.193 0.099 0.100 0.052 0.051 0.054 0.019 0.018 0.030 0.022 0.025 0.010 0.011 0.068 

Max 0.277 0.425 0.490 0.259 0.253 0.156 0.282 0.284 0.148 0.143 0.080 0.078 0.080 0.031 0.033 0.038 0.038 0.052 0.023 0.023 0.090 

SD 0.038 0.062 0.070 0.035 0.029 0.013 0.028 0.029 0.006 0.007 0.008 0.007 0.010 0.003 0.005 0.002 0.004 0.003 0.003 0.011 

CV 20 18 20 18 16 13 16 15 6 7 15 15 18 16 28 7 20 31 30 17 

Npast 28 26 25 21 21 9 12 12 11 11 24 26 25 23 23 5 5 5 5 4 12 

Medianpast 0.202 0.320 0.346 0.191 0.196 0.110 0.166 0.184 0.097 0.096 0.058 0.051 0.054 0.019 0.018 0.033 0.024 0.025 0.011 0.010 0.071 

SDpast 0.046 0.050 0.046 0.026 0.029 0.020 0.035 0.043 0.014 0.010 0.013 0.010 0.008 0.004 0.003 0.008 0.004 0.005 0.002 0.003 0.017 

NISTa 0.056 0.059 0.061 nq nq 0.086 

NISTb 0.230 0.386 0.396 0.200 0.206 0.053 0.057 0.056 0.019 0.015 0.040 0.035 0.036 0.014 0.014 

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

Mean 0.230 0.386 0.396 0.206 0.206 0.054 0.058 0.059 0.020 0.015 0.040 0.035 0.036 0.014 0.014 0.086 

Srep 0.006 0.019 0.007 0.010 0.008 0.004 0.003 0.004 0.000 0.010 0.001 0.001 0.001 0.001 0.003 0.002 

Shet 0.020 0.009 0.013 0.024 0.024 0.004 0.003 0.004 0.002 0.006 0.004 0.001 0.000 0.001 0.001 0.002 

Sanl 0.002 0.001 0.003 

SNIST 0.021 0.021 0.015 0.026 0.026 0.006 0.005 0.006 0.002 0.012 0.004 0.001 0.001 0.001 0.003 0.003 

NAV 0.211 0.365 0.375 0.199 0.196 0.101 0.178 0.193 0.099 0.100 0.053 0.054 0.056 0.019 0.016 0.035 0.029 0.012 0.012 0.077 

NAU 0.055 0.082 0.083 0.049 0.049 0.018 0.031 0.034 0.017 0.017 0.013 0.013 0.013 0.005 0.012 0.008 0.010 0.004 0.004 0.019 

All Lab R eport 
 Round Robin LIV Laboratory Results 

All Values in μg/mL 

Total Zeaxanthin Total Lutein&Zeaxanthin Coenzyme Q10 Phylloquinone 

Lab 294 295 296 297 298 

C5

FSV-BA
 

FSV-BB
 0.042 0.041 0.043 0.027 0.026 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 0.018 0.024 0.023 0.013 0.011 

FSV-BH 0.051 0.032 0.035 0.017 0.017 

FSV-BI 0.037 0.032 0.031 0.017 0.017 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.036 0.016 0.009 0.011 0.012 

FSV-BO 0.046 0.063 0.046 0.023 0.017 

FSV-BP 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.024 0.018 0.033 0.021 0.021 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-BX 0.035 0.032 0.027 0.017 0.017 

FSV-CB 0.029 0.019 0.023 - ­

FSV-CC 

FSV-CD 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 0.035 0.025 0.028 0.015 0.017 

FSV-CP 

FSV-CS 0.037 0.029 0.032 0.018 0.017 

FSV-CT 0.038 0.024 0.025 0.011 nq
 

FSV-CZ
 

FSV-DA
 0.034 0.026 0.029 0.017 0.017 

FSV-DF 

FSV-DI 

FSV-ET 

294 295 296 297 596 

0.100 0.115 0.125 0.069 0.068 

0.111 0.131 0.131 0.070 0.067 

0.106 0.110 0.114 0.060 0.061 

0.064 0.108 0.116 0.060 0.054 

0.115 0.106 0.116 0.054 0.055 

0.121 0.133 0.136 0.068 0.068 

0.099 0.102 0.105 0.068 0.067 

0.0950 0.1286 0.1149 0.0506 0.0535 

0.110 0.114 0.120 0.057 0.059 

0.089 0.100 0.120 0.076 0.074 

0.103 0.095 0.150 0.088 0.094 

0.103 0.103 0.019 0.058 0.056 

0.112 0.114 0.124 0.065 0.066 

0.087 0.093 0.094 0.042 0.054 

0.107 0.119 0.122 0.063 0.063 

0.088 0.083 0.092 0.049 0.050 

0.099 0.107 0.104 0.056 0.057 

0.114 0.118 0.126 0.068 0.067 

0.092 0.090 0.102 0.048 0.055 

0.136 0.142 0.155 0.081 0.084 

0.096 0.111 0.119 

0.106 0.125 0.132 

0.108 0.114 0.121 

0.065 0.062 

0.050 0.039 

0.063 0.064 

294 295 296 297 298 

1.051 0.672 0.645 0.304 0.337 

1.020 0.750 0.830 0.450 0.440 

1.200 0.860 1.000 0.490 0.510 

1.120 0.953 0.940 0.517 0.514 

294 295 296 

0.15 0.41 0.49 

0.16 0.51 0.49 

0.10 0.39 0.41 

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

Min 0.018 0.016 0.009 0.011 0.011 0.064 0.083 0.019 0.042 0.039 1.020 0.672 0.645 0.304 0.337 0.10 0.39 0.41 

Median 0.036 0.026 0.029 0.017 0.017 0.103 0.111 0.120 0.063 0.062 1.086 0.805 0.885 0.470 0.475 0.15 0.41 0.49 

Max 0.051 0.063 0.046 0.027 0.026 0.136 0.142 0.155 0.088 0.094 1.200 0.953 1.000 0.517 0.514 0.16 0.51 0.49 

SD 0.003 0.006 0.006 0.003 0.001 0.011 0.012 0.012 0.010 0.009 0.072 0.113 0.127 0.062 0.072 

CV 8 23 20 19 5 11 11 10 15 15 7 14 14 13 15 

Npast 11 15 15 15 15 22 26 23 21 21 5 8 6 0 0 0 0 0 

Medianpast 0.034 0.025 0.026 0.019 0.020 0.109 0.115 0.120 0.067 0.064 1.000 0.844 0.898 

SDpast 0.006 0.007 0.006 0.004 0.006 0.022 0.016 0.022 0.019 0.016 0.161 0.256 0.213 

NISTa 0.034 nq nq nq nq 0.120 ≥0.086 ≥0.086 ≥0.084 ≥0.042
 

NISTb
 0.037 0.034 0.038 0.021 0.022 0.107 0.118 0.122 0.063 0.064
 

NNIST 4 2 2 2 2 4 2 2 2 2
 

Mean 0.036 0.034 0.038 0.021 0.022 0.114 0.118 0.122 0.047 0.048
 

Srep 0.002 0.003 0.002 0.002 0.001 0.007 0.004 0.006 0.031 0.035
 

Shet 0.002 0.000 0.001 0.001 0.004 0.000 0.003 0.001 0.023 0.018
 

Sanl 0.002 0.009
 

SNIST 0.004 0.003 0.002 0.003 0.004 0.011 0.004 0.006 0.039 0.040
 

NAV 0.036 0.030 0.033 0.019 0.020 0.108 0.115 0.121 0.055 0.055
 

NAU
 0.010 0.010 0.010 0.006 0.007 0.023 0.024 0.025 0.040 0.041 

All Lab R eport 
 

 

 

 

 

Round Robin LIV Laboratory Results
 

All Values 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 

≥x

italics

Analyte Code 294 295 296 297 298 

Total cis-b-Cryptoxanthin FSV-BT 0.03 0.02 0.03 0.02 0.160 

Ubiquinol FSV-BW 0.630 0.640 0.520 0.290 0.280 

Ubiquinone FSV-BW 0.390 0.110 0.310 0.160 0.01 

25-hydroxyvitamin D FSV-CF 0.0220 <0.007 <0.007 0.0100 0.042 

Phytoene FSV-DA 0.013 0.024 0.032 0.011 0.018 

Retinyl stearate FSV-DA 0.005 0.017 0.018 0.007 0.005 

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 at or below the limit of quantification, x

 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 LIV 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-CP
 

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

1 1 1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 2 1 1 2 1 

1 2 

2 1 1 1 1 

2 2 1 1 2 1 1 

1 1 1 1 3 1 2 1 1 

2 1 2 1 1 1 1 2 1 2 1 

1 1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 1 

2 2 

1 2 1 

1 3 

1 2 3 1 1 1 1 1 1 2 

1 1 1 1 2 1 1 1 1 

1 1 1 1 1 1 1 

1 1 1 2 1 

1 1 

2 2 2 1 1 1 1 1 

3 1 3 1 1 1 2 1 1 2 3 1 

1 1 1 2 1 1 1 2 1 1 

2 1 1 1 1 1 2 

1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 

2 2 2 1 1 2 

1 1 1 

1 1 2 1 2 1 2 2 

1 1 1 1 1 1 

1 3 1 

1 1 1 1 1 1 1 1 1 

2 1 1 1 1 1 

2 2 1 1 2 2 

FSV-CS 1 1 2 1 1 1 1 1 1 1 1 

FSV-CT 1 2 1 1 1 1 

Label

Lab

TR 

aT

g/bT

bC

tbC 

aC

TLy 

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 

 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: 

CS = MINIMUM 4,INTEGER 1 



 + C 



 

2 AP2 + 

i 

N 

you

∑ 

= 









− ∑ 

= 

you You Median 

NAU i 1 i 

Youi 

i 1 

NISTb 1 1 1 1 1 1 1 1 1 1 NAU = NIST Assigned Uncertainty n 37 37 24 27 14 24 22 9 25 16 14 24 

For further details, please see 

FSV-CZ 1 2 2 i 

N 

FSV-DA 1 1 1 1 1 1 1 1 1 C = Concordance = 

FSV-DF 1	 1 you 

FSV-DI 2 3 2 2 3 N 2









i 

TR aT g/bT bC tbC aC TLy tLy TbX TLu TZ L&Z	 Duewer DL, Kline MC, Sharpless KE, Brown Thomas J, Gary 

% 1 KT. Micronutrients Measurement Quality Assurance 73 70 71 89 86 83 82 67 80 88 71 92 Program: Helping participants use interlaboratory comparison % 2 24 22 21 11 14 13 18 22 20 13 21 8 exercise results to improve their long-term measurement 

% 3 3 8 8 0 0 4 0 11 0 0 7 0 performance. Anal Chem 1999;71(9):1870-8. 

% 4 0 0 0 0 0 0 0 0 0 0 0 0 

−Median 

NAU i 

1 

FSV-ET 1 1 1 1 

NISTa 1 1 1 1 1 1 1 AP = Apparent Precision = Nyou −

All Lab Report	 Page 6 / 6 

C7
 

Appendix D. Representative “Individualized Report” for RR54 

Each participant in RR54 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 RR54: 

• Total 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 40 

Individualized Round Robin LIV Report: FSV-BA 

Summary 

Serum 294 Serum 295 Serum 296 Serum 297 

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

Total Retinol 1.263 1.269 34 0.454 0.459 35 0.500 0.474 35 0.671 0.643 35 

Retinyl Palmitate 0.05 0.06 11 0.0 0.1 10 0.1 0.1 10 0.02 0.02 9 

α-Tocopherol 17.21 17.02 34 6.76 6.89 35 7.27 7.10 35 2.84 2.83 35 

γ/β-Tocopherol 1.225 1.181 22 1.903 1.844 22 2.074 1.887 22 0.745 0.724 22 

Total β-Carotene 0.054 0.055 25 0.326 0.334 25 0.350 0.343 25 0.048 0.047 25 

trans-β-Carotene 0.051 0.051 12 0.310 0.301 12 0.334 0.320 12 0.047 0.046 12 

Total cis-β-Carotene 0.003 0.005 5 0.017 0.031 7 0.016 0.028 8 0.001 6 

Total α-Carotene 0.025 0.026 22 0.024 0.028 23 0.026 0.029 22 0.003 0.006 15 

trans-Lycopene 0.104 0.101 9 0.178 0.178 9 0.192 0.193 9 0.094 0.099 9 

Total β-Cryptoxanthin 0.061 0.053 23 0.058 0.054 23 0.061 0.056 23 0.021 0.019 23 

Total Lutein&Zeaxanthin 0.100 0.108 23 0.115 0.115 23 0.125 0.121 23 0.069 0.055 23 

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: d

Individualized Report 
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

Total Retinol 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 2 / 12 

D3
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

Retinyl Palmitate 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298 

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 3 / 12 

D4
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

α-Tocopherol 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298 

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 4 / 12 

D5
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

γ/β-Tocopherol 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 5 / 12 

D6
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

Total β-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 6 / 12 

D7
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

trans-β-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298 

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 7 / 12 

D8
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

Total α-Carotene 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298 

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 8 / 12 

D9
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

trans-Lycopene 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 9 / 12 

D10
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

Total β-Cryptoxanthin 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 10 / 12 

D11
 

 Set 1 of 40 

Individualized RR LIV Report: FSV-BA 

Total Lutein&Zeaxanthin 

Apparent Precision, SD 

[Analyte], μg/mL 

203273294266277282295271275279296285297286298

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%) 

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 

#294 Lyophilized: #203 RR33, #273 RR49 Augmented with R, RP, αT, γT, and δT 

#295 Lyophilized: #266 RR48, #277 RR50, #282 RR51 Same pool as #296, native 

#296 Fresh-frozen: #271 RR49, #275 RR50, #279 RR51 Same pool as #295, native 

#297 Fresh-frozen: #285 RR52 Same pool as #298, trans-Retinol augmented 

#298 Fresh-frozen: #286 RR52 Same pool as #297, cis-Retinol augmented 

Individualized Report Page 11 / 12 

D12
Set 1 of 40 

Individualized Round Robin LIV Report: FSV-BA
 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total β-Carotene 

D13

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

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

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

Individualized Report 
 

 

Appendix E. Shipping Package Inserts for RR19 

The following five items were included in each package shipped to an RR19 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
March 26, 2003 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute af Standards and Technalagy 

Gaithersburg, Maryland 20899-

. Enclosed are samples for the vitamin C round robin study (RR 19) for the 2003 NIST 

Micronutrients Measurement Quality Assurance Program. RR 19 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: srminfo@nist.gov) 

Please return your results for RR 19 using the attached form by September 19, 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: "bthomas@nist. v; or mail/fax queries to the above address. 

Enclosures 

NlSI 

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 0.19 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
Participant #: Date: 

Vitamin C Round Robin 19 

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
	

Please return before September 19, 2003 to: 

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 19 

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 #12 μmol/L of Sample 

Test Sample #25 μmol/L of Sample 

Test Sample #44 μmol/L of Sample 

Test Sample #66 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: 

Please return before September 19, 2003 to: 

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 19 

NIST Micronutrients Measurement Quality Assurance Program 

Packing List and Shipment Receipt Confirmation Form 

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

Sample Form 

VitC #12 Liquid frozen (1:1 serum:10% MPA) 

VitC #25 Liquid frozen (1:1 serum:10% MPA) 

VitC #44 Liquid frozen (1:1 serum:10% MPA) 

VitC #66 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 #12, #25, #44, and #66 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 samples VitC #12, #25, #44, and #66 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 RR19 

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. 

F1
November 18, 2003 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Ina~ af Standards and Tachnalagy 

Gaithersburg, Maryland 20899- · 

Enclosed is the summary report of the results for Round Robin 19 (RR19) for the measurement of 

tot_al 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 14e measurements are defined as 0.74x interquartile range and the 

estim~te coeffid.ents of variation ( eCV) are defined as 1 OOx eSD/median. 

RR19 consists of four 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 Stahdard 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 certifa;d values, we suggest that you contact us 

for consultation. · 

As you are aware, samples for the vitamin C round robin study (RR 20) for the 2004 NIST Vitamin 

C in Serum QA Program were recently shipped (during the week of November 17). It is critical 

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

have arrived, if you have not done so already. 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. 

We are pleased to announce ~at due to the generous funding support from the Centers for Disease 

Control in Atlanta, a second Vitamin C Round Robin (RR21) will be distributed, at no cost to you, 

during the week of May 3, 2004. As before, we will send you a reminder via e-~ail or fax about a · 

week prior to shipment. 

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

jbthomas(@nist.gov; or fax: 301-977-0685. 

ical Chemistry Division 

Chemical Science and Technology Laboratory · 

Enclosures 

F2

N•Si 
 

The NIST M2QAP Vitamin C Round Robin 19 (RR19) 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 and for four serum test samples. 

2 Graphical summary of your RR 19 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR19 

samples and control/calibration solutions. 

Test Samples. Three unknowns were distributed in RR19. 

S19:1 Serum 12, ampouled in late 2001, previously distributed as sample S16:2 (RR16, Mar-02). 

This is the base serum used to prepare the augmented test samples. The TAA level in this 

material is low (1 to 2 mmol/L), but it is not zero. 

S19:2 Serum 25, ampouled in late 2001, previously distributed as sample 17:1 (RR17, Sep-02). An 

augmented serum. 

S19:3 Serum 44, ampouled in late 2001, previously distributed as sample 18:2 (RR18, Mar-03). An 

augmented serum. 

S19:4 Serum 66, SRM 970 level 1, ampouled in mid-1998. This material was distributed with 

identification in RR11 (Oct-98) and RR12 (Mar-99) and as samples S13-1 (RR13, Mar-00), 

S14-3 (RR14, Mar-01), S15:1 (RR15, Sep-01), and 16:1 (RR16, Mar-02). 

Results. 

1)	 All participants who prepared the four control/calibration solutions (the three “Dilute Solutions” and 

the 5% MPA “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 (≈0.55 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) is little changed by “correcting” 

the reported test sample results with the observed Calibration Parameters. 

3)	 There has been no significant change in TAA average level or among-participant variability in any of 

the test samples. 

4)	 The enclosed figure displays the interlaboratory estimated standard deviations (SDs) as a function of 

the median [TAA] for both the dilute solutions prepared from the solid control and for the serumbased test samples of RR16, RR17, RR18, and RR19. The SDs of both matrices appear to be linearly 

related to the TAA level. Since both a level-independent SD viability component of ≈1 mmol/L, the 

estimated percent relative SDs (%RSDs) of the two matrices are not constant. The limiting %RSD of 

the solutions prepared from the control material is ≈6%; the limiting %RSD of the serum-based test 

samples is about 12%. 

F3
 

Relative Standard Deviation, % 20 

15
 

10
 

5
 

0 

0 

1 

2 

3 

4 

5 

6 

7 

Standard Deviation, mmol/L 

Solution controls 

Serum test samples 

0 10 20 30 40 50
 

Median, mmol/L
 

Expected Variability at Given Total Ascorbic Acid Levels for 

Solution Controls and Serum Test Samples, RR 16 – 19. 

F4
Appendix G. “All-Lab Report” for RR19 

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" 19 - September 2003 

Control / Calibration Samples MPA Dilute Solution 1 

G2

Calibration Parameters Density Spectrophotometry Measured, μmo

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 S19:1 S19:2 S19:3 

λmax Amax 

VC-MA 13/11/03 59.0 29.5 14.6 61.7 31.8 17.5 0.0 1.08 1.03 0.998 1.2 1.029 243. 0.5839 561.9 nq 9.2 35.

VC-MB 01/05/03 59.9 29.9 15.1 50.9 25.0 13.2 2.6 1.60 0.81 0.998 1.2 1.031 244. 0.6116 579.7 3.1 10.8 33.

VC-MC 12/05/03 57.2 28.6 14.3 58.0 32.9 16.1 0.1 1.44 1.01 0.995 2.2 1.031 243. 0.5294 525.8 0.7 12.0 41.

VC-ME 12/09/03 55.0 27.5 13.8 52.5 26.1 12.9 0.2 -0.02 0.95 1.000 0.2 1.026 244. 0.5473 564.6 0.2 8.1 29.

VC-MG 17/09/03 57.4 28.9 14.8 62.3 30.5 18.1 0.0 0.65 1.07 0.998 1.4 1.032 243.8 0.5685 562.1 4.5 10.0 36.

VC-MH 21/05/03 58.5 29.4 14.2 58.8 29.7 14.1 0.0 -0.05 1.01 1.000 0.2 1.030 243.7 0.5719 555.4 0.1 9.4 33.

VC-MI 22/05/03 58.6 28.7 14.0 62.9 30.1 14.6 0.0 -0.32 1.07 1.000 0.4 1.030 nq 11.2 41.

VC-MK 15/09/03 60.5 29.8 14.8 52.7 28.5 14.3 0.8 1.60 0.86 0.998 1.3 1.033 244. 0.5984 561.6 4.6 13.7 34.

VC-MO 19/09/03 57.5 28.4 14.2 59.2 29.5 16.1 1.5 1.59 1.14 1.000 0.5 1.028 244. 0.5395 532.7 0.7 9.1 31.

VC-MR 24/06/03 57.3 29.1 14.4 55.9 28.3 14.1 0.0 0.02 0.97 1.000 0.1 1.028 243. 0.5610 555.8 0.1 8.4 32.

VC-MS 21/04/03 56.8 28.2 13.8 24.2 10.1 0.0 -0.59 0.86 0.993 1.4 1.028 244. 0.5637 563.5 nq 5.1 19.

VC-MT 15/12/03 0.00 1.00 0.9 9.4 31.

VC-MY 10/09/03 0.00 1.00 < 5.7 7.5 28.

NIST 24/10/03 59.1 29.2 14.0 58.7 32.1 13.6 0.0 0.47 1.00 0.996 2.0 1.024 243. 0.5723 549.7 1.4 9.8 34.

N 11 11 11 

58.0 28.9 14.4 

1.5 0.7 0.4 

55.0 27.5 13.8 

57.2 28.5 14.1 

57.5 28.9 14.3 

58.8 29.5 14.7 

60.5 29.9 15.1 

1.4 0.8 0.5 

2 3 4 

10 11 11 11 

57.5 28.8 14.6 0.5 

4.3 2.7 2.2 0.9 

50.9 24.19 10.1 0.0 

53.5 27.18 13.6 0.0 

58.4 29.46 14.3 0.0 

61.0 30.32 16.1 0.5 

62.9 32.91 18.1 2.6 

5.3 1.79 2.1 0.0 

9 6 15 

N 11 10 10 10 9 13 1

Average Average 1.030 243.7 0.5675 556.3 1.6 9.5 33.

SD SD 0.002 0.5 0.0256 15.8 1.9 2.1 5.

Min Min 1.026 243.0 0.5294 525.8 0.1 5.1 19.

%25 %25 1.028 243.2 0.5507 555.5 0.2 8.4 31.

Median Median 1.030 243.9 0.5661 561.8 0.7 9.4 33.

%75 %75 1.031 244.0 0.5809 563.1 3.1 10.8 35.

Max Max 1.033 244.0 0.6116 579.7 4.6 13.7 41.

MADe MADe 0.002 0.1 0.0271 6.5 0.8 2.0 4.

CV CV 0.19 0.06 5 1 22 1

All Lab Report 
Appendix H. Representative “Individualized Report” for RR19 

Each participant in RR19 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" 19 Report: Participant VC-MA
 

Date RR Method 

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 

11/13/03 19 HPLC-EC 

MPA Dilute Solution 1 Control/Calibration Solutions 

Density Spectrophotometry Ymeas = Inter + Slope* Xgrav 

g/mL 

1.028 

1.027 

1.032 

1.026 

1.026 

1.026 

λmax Amax E1% 

243.0 0.541 547.7 

243.0 0.547 556.5 

242.0 0.575 576.5 

242.0 0.552 551.0 

244.0 0.509 563.1 

243.0 0.584 561.9 

Inter Slope R2 SEE 

-0.9 1.03 0.999 1.09 

0.0 1.04 1.000 0.05 

-0.4 1.07 0.999 0.90 

-0.3 1.06 1.000 0.49 

-0.1 1.02 1.000 0.18 

1.1 1.03 0.998 1.24 

Mean 1.027 242.8 0.55 559.5 

SD 0.002 0.8 0.03 10.3 

CV 0.22 0.31 4.8 1.8 

[TAA] mmol/Lsample 

Date RR Sample 

11/18/02 16 S16:2 

11/13/03 19 S19:1 

12/12/02 17 S17:1 

Rep1 Rep2 Fadj Mean SDdup 

0.0 0.1 1.0 0.0 0.0 

na na 1.0 

N Mean SDrepeat SDreprod 

1 0.0 0.0 

2 9.4 0.4 0.4 

11/13/03 19 S19:2 

03/20/03 18 S18:2 2 35.7 0.4 0.4 

11/13/03 19 S19:3 

09/23/98 11 S11:1:A 9 8.0 0.4 0.6 

09/23/98 11 S11:1:B 

04/02/99 12 S12:1:A 

04/02/99 12 S12:1:B 

09/17/01 13 S13:1 

09/27/01 14 S14:3 

09/18/01 15 S15:1 

11/18/02 16 S16:1 

11/13/03 19 S19:4 

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 

9.9 9.1 1.0 9.5 0.6 

9.2 9.1 1.0 9.2 0.1 

35.1 36.0 1.0 35.6 0.6 

35.9 35.8 1.0 35.9 0.1 

15.5 13.9 0.5 7.4 0.6 

15.5 13.9 0.5 7.4 0.6 

14.5 15.8 0.5 7.6 0.5 

14.5 15.8 0.5 7.6 0.5 

8.4 8.5 1.0 8.5 0.1 

8.0 7.7 1.0 7.8 0.2 

8.9 8.7 1.0 8.8 0.1 

8.8 8.8 1.0 8.8 0.0 

7.8 8.6 1.0 8.2 0.5 

Individualized Report Page 1/2 

H2
 

 

 

Set 1 of 14 

Vitamin C "Round Robin" 19 Report: Participant VC-MA 

Total Ascorbic Acid 

[Total Ascorbic Acid], μmol/L 

Your [Total Ascorbic Acid], μmol/L

S17:1S19:2S18:2S19:3S11:1S12:1S13:1S14:3S15:1S16:1S19:4 

Median [Total Ascorbic Acid], μmol/L 

Apparent Precision, SD 

Concordance, SD 

3rd Quartile (75%) You, RR 19 NIST, RR 19 Median (50%) You, RR 14-18 Others, RR 19 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 

S19:1 Serum 12, previously distributed in RR 16, is a "blank" control: not displayed in the box-plot. 

S19:2 Serum 25, previously distributed in RR 17. 

S19:3 Serum 44, previously distributed in RR 18. 

S19:4 SRM 970 Level 1, previously distributed as in RRs 11, 12, 13, 14, 15, and 16 

Individualized Report Page 1/2 

H3