NISTIR 7880-11 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2007 

Comparability Studies 

Results for Round Robin LXI 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 26 Ascorbic Acid in Human Serum 

David L. Duewer 

Jeanice B. Thomas 

 

 

 

 

 

 

NISTIR 7880-11
 

NIST Micronutrients Measurement 

Quality Assurance Program 

Winter 2007 

Comparability Studies 

Results for Round Robin LXI 

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 26 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 

Winter 2007 MMQAP measurement comparability improvement studies: 1) Round Robin LXI FatSoluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 26 Total Ascorbic Acid in 

Human Serum. The materials for both studies were shipped to participants in November 2006; 

participants were requested to provide their measurement results by March 5, 2007. 

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

Round Robin 26: Vitamin C in Human Serum............................................................................... 2
	

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

Appendix A. Shipping Package Inserts for RR61........................................................................ A1
	

Appendix B. Final Report for RR61 .............................................................................................. B1 

Appendix C. “All-Lab Report” for RR61 ...................................................................................... C1
	

Appendix D. Representative “Individualized Report” for RR61 ............................................... D1
	

Appendix E. Shipping Package Inserts for RR26 ......................................................................... E1
	

Appendix F. Final Report for RR26............................................................................................... F1
	

Appendix G. “All-Lab Report” for RR26..................................................................................... G1
	

Appendix H. Representative “Individualized Report” for RR26............................................... 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 LXI: Fat-Soluble Vitamins and Carotenoids in Human Serum 

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

LXI comparability study (hereafter referred to as RR61) received one lyophilized and four liquidfrozen human serum test samples for analysis. Unless multiple vials were previously requested, 

participants received one vial of each serum. These sera were shipped on dry ice to participants in 

November 2006. 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 RR61 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 26: Vitamin C in Human Serum 

Participants in the MMQAP Vitamin C in Human Serum Round Robin 26 comparability study 

(hereafter referred to as RR26) 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 November 2006. 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 RR26 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. 

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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 RR61 

The following three items were included in each package shipped to an RR61 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
UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

November 8, 2006 

Dear Colleague: 

Enclosed are the samples (Sera 329-333) for the first fat-soluble vitamins and carotenoids in serum round 

robin study (Round Robin LXI) for the fiscal year (FY) 07 NIST Micronutrients M.e~surement Quality 

Assurance Program. You will find one vial of each of four liquid-frozen and one 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 March 5, 2007. Results received more than two weeks after the due date will not be included in 

the summary report for this round robin study. 

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 int~rmittent 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 (Sera 329-332). 

For consistency, we request that laboratories use the following absorptivities (dL/g.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 LXI to: 

Micronutrients Measurement Quality Assurance Program 

NIST 

100 Bureau Drive Stop 8392 

Gaithersburg, MD ~0899-8392 

Fax: (301) 977-0685 

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

'bthomas@nist.gov; or mai fax queries to_t hove address. 

.~ Brown Thomas 

ch Chemist 

ical Chemistry Division 

· Chemical Science and Technology Laboratory 

Enclosures 

. ·r 

NISI 

A2
 

 

 

Participant #: ________ Date: _____________ 

Round Robin LXI: Human Sera 

NIST Micronutrients Measurement Quality Assurance Program 

Analyte 329 330 331 332 333 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 #329, 330, 331, and 332 frozen when received? Yes | No 

Comments: 

Mail: M2QAP
 

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

Gaithersburg, MD 20899-8392 5-Mar-2007 Email: David.Duewer@NIST.gov
 

A3
 

 

 

 

Participant #: ________ Date: _____________ 

Fat-Soluble Vitamins Round Robin LXI
 

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 Form Reconstitute? 

#329 

#330 

#331 

#332 

#333 

Liquid frozen 

Liquid frozen 

Liquid frozen 

Liquid frozen 

Lyophilized 

No 

No 

No 

No 

Yes (1 ml H2O) 

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 

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Appendix B. Final Report for RR61 

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
April 26, 2007 

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 LXI (RR6 I) of the 2007 NIST 

Micronutrients Measurement Quality Assurance Program (M2

QAP) for the fat-soluble vitamins and 

carotenoids in human serum. Included in this report are: l) 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 comparability. 

Data for evaluating laboratory performance in RR6 l are provided in text "Score Card" summary, page 7 

of the All Lab Report. Laboratory comparability is summarized as follows: results rated 1 to 3 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 in the graphical "target plot" summary, last 

· page of your Individualized Report. 

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

unit ofSRM 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 second 2007 QA interlaboratory exercise will be shipped starting the week of June 4, 

2007. 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. 

We look forward to meeting with you at the Micronutrients Measurement Quality Assurance Workshop 

that is being held in conjunction with the Experimental Biology meeting on May 2, 2007 at the 

Convention Center in Washington, DC. 

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' e Brown 

~ 

Thomas 

~ rch Chemist 

A a ical Chemistry Division 

Chemical Science and Technology Laboratory 

Cc: L.C. Sander 

D.L. Duewer 

B2

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The NIST M2QAP Round Robin LXI (RR61) report consists of: 

Page “All Lab” Report 

1-5 A listing of all results and statistics for all analytes. 

6 A legend for the list of results and statistics. 

7 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. The five sera below were distributed in RR61. 

Serum
	

329 

330 

331 

332 

333 

Description
	

Fresh-frozen, native, single-donor serum prepared in 

Spring, 2006. 

Fresh-frozen, a 15:16 blend of the #329 and #331 

sera (i.e., #330 = (15×#324 + 16×#326)/31, prepared 

in Spring, 2006. 

Fresh-frozen, native, single-donor serum prepared in 

Spring, 2006. 

Fresh-frozen, native, single-donor, commercially 

obtained serum prepared in 2002. The same 

material was used to prepare #333. 

Lyophilized, native, single-donor, commercially 

obtained serum prepared in 2002. The same 

material was used to prepare #332. 

Prior Distributions
	

#326:RR60-9/06 

#292:RR53-2/03, #301:RR55-3/04, 

#313:RR57-3/05, #323:RR59-3/06 

#290:RR53-2/03, #300:RR55-3/04, 

#312:RR57-3/05, #322:RR59-3/06 

Results 

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

in either the fresh-frozen or lyophilized serum of the {332, 333} pair. These materials have been in -

-80 °C storage for more than four years. The stability of the fresh-frozen material in this and other 

sera pairs provides strong support for continued use of fresh-frozen rather than lyophilized materials 

in this program. 

2)		 Measurand Additivity. Serum 330 was prepared as a mixture of two native, single-donor sera. Using 

the correct method of analysis, the median values in Serum 325 are as expected from the Sera 329 

and 331 medians and their 15:16 blending ratio. (Previous additivity studies were incorrectly 

analyzed. The curved lines connecting the three sera in the current graphs are correct for reporting 

results on a logarithmic y-axis. This topic will be discussed in more detail at the Workshop.) 

B3
3)		 Report of Unusual Performance of High-purity Retinol Standards. Our colleague Fernando GranadoLorencio, Hospital Universitario Puerta de Hierro (Madrid), reports unusually high chromatographic 

response per ng injected for recently purchased high-purity retinol standards from Sigma. The new 

material appears to be of about 20% higher purity than the older material. Similar behavior was 

noted by other members of the European Standardization Methods Committee during their revision 

of a candidate reference method for vitamin A in foods. 

B4
 

 

 

 

 

 

Appendix C. “All-Lab Report” for RR61 

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

two exceptions: 

• the participant identifiers (Lab) have been altered. 

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

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

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

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

summary results of the study. 

C1
Round Robin LXI Laboratory Results 

All Results in μg/mL 

Total Retinol trans-Retinol Retinyl Palmitate 

C2

Lab 329 330 331 332 333 329 330 331 332 333 329 330 331 332 333 329 

FSV-BA 0.559 0.433 0.326 0.697 0.709 0.068 0.057 0.070 0.120 0.114 24.43 

FSV-BB 0.485 0.388 0.284 0.628 0.617 0.055 0.033 0.011 0.077 0.073 25.17 

FSV-BC 0.512 0.396 0.300 0.651 0.619 

FSV-BD 0.536 0.444 0.331 0.696 0.628 24.50 

FSV-BE 0.553 0.390 0.314 0.635 0.607 28.58 

FSV-BF 0.520 0.400 0.290 0.610 0.600 25.00 

FSV-BG 0.563 0.431 0.316 0.702 0.653 0.106 0.084 0.066 0.172 0.152 26.48 

FSV-BH 0.422 0.398 0.262 0.584 0.608 21.44 

FSV-BI 0.472 0.364 0.276 0.577 0.561 0.098 nd nd 0.110 0.105 23.41 

FSV-BJ 0.496 0.379 0.280 0.593 0.581 0.050 0.026 0.012 0.096 0.097 27.06 

FSV-BK 0.602 0.427 0.320 0.667 0.637 25.37 

FSV-BL 0.520 0.370 0.290 0.630 0.600 21.50 

FSV-BM 0.519 0.404 0.325 0.634 0.614 26.90 

FSV-BN 0.421 0.352 0.251 0.553 0.536 0.050 0.032 0.013 0.100 0.098 22.46 

FSV-BO 0.507 0.384 0.315 0.670 0.636 21.50 

FSV-BQ 0.552 0.428 0.352 0.682 0.669 21.00 

FSV-BR 0.527 0.402 0.305 0.663 0.661 23.06 

FSV-BS ≥0.469 ≥0.366 ≥0.274 ≥0.588 ≥0.557 0.469 0.366 0.274 0.588 0.557 24.82 

FSV-BT 0.599 0.471 0.342 0.666 0.604 23.26 

FSV-BU 0.329 0.406 0.296 0.565 0.471 23.08 

FSV-BV 0.424 0.325 0.262 0.645 0.605 22.95 

FSV-BW 0.500 0.390 0.300 0.650 0.610 0.090 0.050 0.010 0.260 0.230 22.90 

FSV-BX ≥0.510 ≥0.390 ≥0.306 ≥0.647 ≥0.633 0.510 0.390 0.306 0.647 0.633 23.69 

FSV-CC 0.550 0.430 0.320 0.700 0.660 0.540 0.430 0.320 0.700 0.650 24.10 

FSV-CE 0.480 0.360 0.300 0.610 0.710 25.00 

FSV-CF 0.497 0.378 0.282 0.669 0.674 24.20 

FSV-CG 0.530 0.413 0.322 0.647 0.638 23.43 

FSV-CI ≥0.462 ≥0.362 ≥0.289 ≥0.596 ≥0.581 0.462 0.362 0.289 0.596 0.581 0.045 0.026 0.024 0.092 0.082 23.59 

FSV-CS 0.585 0.437 0.329 0.789 0.650 22.54 

FSV-CW 0.513 0.341 0.263 0.611 0.597 0.036 0.014 0.007 0.091 0.086 25.26 

FSV-CZ 0.529 0.402 0.304 0.647 0.608 23.80 

FSV-DD ≥0.600 ≥0.340 ≥0.380 ≥0.730 ≥0.680 0.600 0.340 0.380 0.730 0.680 

FSV-DF 0.500 0.376 0.303 0.637 0.765 

FSV-DI 0.523 0.418 0.324 0.642 0.624 0.059 0.033 0.010 0.094 0.091 24.20 

FSV-DV 0.568 0.424 0.326 0.696 0.680 21.90 

FSV-EE 0.454 0.309 0.266 0.550 0.508 19.90 

N 32 32 32 32 32 5 5 5 5 5 10 9 9 10 10 33 

Min 0.329 0.309 0.251 0.550 0.471 0.462 0.340 0.274 0.588 0.557 0.036 0.014 0.007 0.077 0.073 19.90 

Median 0.520 0.399 0.304 0.646 0.618 0.510 0.366 0.306 0.647 0.633 0.057 0.033 0.012 0.098 0.098 23.69 

Max 0.602 0.471 0.352 0.789 0.765 0.600 0.430 0.380 0.730 0.680 0.106 0.084 0.070 0.260 0.230 28.58 

SD 0.042 0.035 0.029 0.043 0.038 0.026 0.018 0.010 0.019 0.018 1.56 

CV 8 9 10 7 6 45 54 87 19 19 7 

Npast 0 0 32 33 34 0 0 5 7 7 0 0 8 12 12 0 

Medianpast 0.309 0.641 0.605 0.310 0.643 0.603 0.037 0.099 0.093 

SDpast 0.023 0.045 0.044 0.000 0.020 0.020 0.030 0.021 0.019 

NAV 

NAU 

0.520 0.399 0.304 0.646 0.618 

0.042 0.035 0.029 0.051 0.049 

0.489 0.378 0.298 0.622 0.607 

0.042 0.035 0.029 0.051 0.049 

0.057 0.033 0.012 0.098 0.098 

0.026 0.018 0.011 0.026 0.026 

23.69 

1.89 

All Lab Report 
Round Robin LXI Laboratory Results 

All Results in μg/mL 

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

C3

Lab 329 330 331 332 333 329 330 331 332 333 329 330 331 332 333 329 33

FSV-BA 1.06 2.569 3.83 1.94 1.87 0.065 0.065 0.079 0.064 0.052 0.580 0.351 0.158 0.132 0.127 0.548 0.3

FSV-BB 0.90 2.325 3.54 1.74 1.67 0.045 0.038 0.059 0.037 0.032 0.533 0.306 0.130 0.106 0.109 0.507 0.2

FSV-BC 

FSV-BD 

FSV-BE 1.10 2.743 4.33 2.06 1.95 0.528 0.356 0.169 0.134 0.106
 

FSV-BF
 0.81 2.340 3.54 1.79 1.77 0.436 0.272 0.121 0.102 0.093 

FSV-BG 0.86 2.630 4.07 2.14 1.98 0.674 0.410 0.179 0.172 0.177 

FSV-BH 0.67 2.181 3.16 1.57 1.53 0.580 0.362 0.145 0.119 0.116 0.548 0.3

FSV-BI 0.91 2.380 3.71 1.95 1.82 0.544 0.313 0.139 0.111 0.108
 

FSV-BJ
 0.94 2.573 3.84 1.76 1.72 0.617 0.359 0.128 0.130 0.126 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.69 2.041 3.01 1.52 1.48 0.491 0.323 0.136 0.113 0.109 0.453 0.3

FSV-BO 0.90 2.400 3.60 1.70 1.60 0.573 0.358 0.177 0.165 0.114 0.500 0.3

FSV-BQ 

FSV-BR 

FSV-BS 1.24 2.387 3.45 1.80 1.84 ≥0.554 ≥0.345 ≥0.167 ≥0.134 ≥0.129 0.554 0.3

FSV-BT 0.86 2.021 3.12 1.52 1.49 0.381 0.284 0.282 0.282 0.289 0.520 0.336 0.136 0.135 0.135 0.488 0.3

FSV-BU 1.05 2.690 4.26 2.04 2.25 0.466 0.278 0.097 0.126 0.110 

FSV-BV 0.83 2.181 3.46 1.71 1.60 0.584 0.337 0.160 0.121 0.114 

FSV-BW 1.24 3.470 5.41 2.50 2.39 0.520 0.340 0.160 0.140 0.130 

FSV-BX 1.01 2.475 3.56 1.77 1.72 ≥0.527 ≥0.307 ≥0.139 ≥0.119 ≥0.110 0.527 0.3

FSV-CC 

FSV-CE 0.780 0.440 0.150 0.220 0.040 

FSV-CF 

FSV-CG 0.88 2.557 3.90 1.92 1.82 0.209 0.260 0.296 0.159 0.121 0.548 0.322 0.143 0.117 0.115 0.507 0.2

FSV-CI 0.80 2.349 4.12 1.82 1.69 ≥0.480 ≥0.316 ≥0.150 ≥0.134 ≥0.139 0.480 0.3

FSV-CS 1.23 3.033 4.05 2.30 2.08 0.556 0.310 0.131 0.136 0.107 

FSV-CW 1.25 2.690 3.80 2.10 2.00 0.050 0.080 0.120 0.080 0.070 ≥0.531 ≥0.284 ≥0.141 ≥0.138 ≥0.134 0.531 0.2

FSV-CZ 0.693 0.396 0.153 0.180 0.171 

FSV-DD 

FSV-DF 

FSV-DI 0.90 2.430 3.63 1.84 1.78 0.033 0.048 0.061 0.042 0.042 0.498 0.315 0.149 0.113 0.111 

FSV-DV 

FSV-EE 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

21 

0.67 

0.90 

1.25 

0.15 

17 

0 

21 

2.021 

2.430 

3.470 

0.215 

9 

0 

21 

3.01 

3.71 

5.41 

0.38 

10 

24 

3.62 

0.24 

21 

1.52 

1.82 

2.50 

0.22 

12 

22 

1.83 

0.14 

21 

1.48 

1.78 

2.39 

0.21 

12 

22 

1.74 

0.11 

6 

0.033 

0.058 

0.381 

0.094 

164 

0 

6 

0.038 

0.073 

0.284 

0.121 

167 

0 

6 

0.059 

0.100 

0.296 

0.131 

131 

5 

0.076 

0.004 

6 

0.037 

0.072 

0.282 

0.068 

95 

6 

0.063 

0.024 

6 

0.032 

0.061 

0.289 

0.047 

78 

6 

0.067 

0.023 

19 

0.436 

0.548 

0.780 

0.046 

8 

0 

19 

0.272 

0.337 

0.440 

0.033 

10 

0 

19 

0.097 

0.145 

0.179 

0.019 

13 

26 

0.147 

0.019 

19 

0.102 

0.130 

0.220 

0.017 

13 

26 

0.120 

0.017 

19 

0.040 

0.114 

0.177 

0.013 

12 

26 

0.114 

0.016 

11 

0.453 

0.507 

0.554 

0.034 

7 

0 

0.2

0.3

0.3

0.0

0.90 2.43 3.71 1.82 1.78 

0.15 0.24 0.38 0.22 0.21 

0.058 0.073 0.100 0.072 0.061 

0.094 0.121 0.131 0.068 0.047 

0.548 0.337 0.145 0.130 0.114 

0.076 0.049 0.023 0.021 0.019 

0.507 0.3

0.053 0.0

All Lab Report 
Round Robin LXI Laboratory Results 

All Results in μg/mL 

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

Lab 329 330 331 332 333 

C4

FSV-BA 0.033 0.021 0.010 0.006 0.006 

FSV-BB 0.026 0.013 0.005 0.004 0.005 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 

FSV-BG 

FSV-BH 0.032 0.018 na na na 

FSV-BI 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.040 0.026 0.012 0.009 0.009 

FSV-BO 0.073 0.048 0.026 0.026 nd 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 0.027 0.017 0.007 0.005 0.005 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-BX 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 0.041 0.024 0.010 0.007 0.007 

FSV-CI 

FSV-CS 

FSV-CW 

FSV-CZ 

FSV-DD 

FSV-DF 

FSV-DI 

FSV-DV 

FSV-EE 

329 330 331 332 333 

0.316 0.154 0.016 0.084 0.082 

0.284 0.134 0.013 0.068 0.069 

0.353 0.155 0.014 0.087 0.089 

0.292 0.146 0.022 0.093 0.091 

0.319 0.160 0.010 0.078 0.077 

0.304 0.145 0.016 0.075 0.070 

0.404 0.172 0.012 0.089 0.092 

0.290 0.151 0.014 0.080 0.078 

0.325 0.162 0.017 0.105 0.089 

0.353 0.187 0.046 0.113 0.109 

0.225 0.132 0.021 0.083 0.080 

0.299 0.138 0.018 0.082 0.070 

0.394 0.161 0.014 0.087 0.082 

0.260 0.130 0.010 0.060 0.052 

≥0.285 ≥0.140 ≥0.021 ≥0.081 ≥0.075 

0.365 0.173 

0.302 0.180 

0.327 0.148 

0.348 0.143 

0.247 0.126 

0.018 0.092 0.091 

0.055 0.120 0.113 

0.012 0.094 0.077 

0.007 0.083 0.082 

0.055 0.094 0.090 

329 330 331 332 333 

0.262 0.427 0.577 0.507 0.486 

0.263 0.416 0.550 0.486 0.468 

0.261 0.421 0.593 0.541 0.494 

0.300 0.534 0.654 0.631 0.626 

0.280 0.499 0.636 0.566 0.563 

0.228 0.374 0.487 0.438 0.389 

0.269 0.421 0.537 0.508 0.483 

0.236 0.445 0.542 0.494 0.489 

0.307 0.490 0.737 0.710 0.525 

0.306 0.496 0.658 0.552 0.531 

0.228 0.412 0.513 0.498 0.470 

0.261 0.410 0.332 0.508 0.426 

0.293 0.475 0.634 0.559 0.508 

0.260 0.480 0.720 0.690 0.640 

0.291 0.455 0.592 0.502 0.496 

0.301 0.433 0.569 0.601 0.522 

0.278 0.447 0.583 0.537 0.519 

329 

0.121 0

0.096 0

0.133 0

0.100 0

0.085 0

0.119 0

0.100 0

N 7 7 6 6 5 19 19 19 19 19 17 17 17 17 17 7 

Min 0.026 0.013 0.005 0.004 0.005 0.225 0.126 0.007 0.060 0.052 0.228 0.374 0.332 0.438 0.389 0.085 0

Median 0.033 0.021 0.010 0.007 0.006 0.316 0.151 0.016 0.087 0.082 0.269 0.445 0.583 0.537 0.496 0.100 0

Max 0.073 0.048 0.026 0.026 0.009 0.404 0.187 0.055 0.120 0.113 0.307 0.534 0.737 0.710 0.640 0.133 0

SD 0.008 0.006 0.003 0.002 0.001 0.044 0.015 0.005 0.009 0.010 0.024 0.044 0.070 0.047 0.031 0.016 0

CV 25 27 28 37 25 14 10 32 11 12 9 10 12 9 6 16 

Npast 0 0 5 6 6 0 0 19 22 22 0 0 22 22 22 0 

Medianpast 0.009 0.007 0.007 0.017 0.079 0.074 0.587 0.506 0.479 

SDpast 0.006 0.002 0.003 0.004 0.012 0.012 0.056 0.067 0.059 

NAV 0.033 0.021 0.010 0.007 0.006 0.316 0.151 0.016 0.087 0.082 0.269 0.445 0.583 0.537 0.496 0.100 0

NAU 0.012 0.007 0.004 0.003 0.003 0.080 0.041 0.006 0.025 0.024 0.062 0.094 0.117 0.110 0.103 0.017 0

All Lab Report 
Round Robin LXI Laboratory Results 

All Results in μg/mL 

Total β-Cryptoxanthin Total α-Cryptoxanthin Total Lutein Tota

C5

Lab 329 330 331 332 333 329 330 331 332 333 329 330 331 332 333 329 330 

FSV-BA 0.105 0.121 0.128 0.067 0.064 0.021 0.036 0.045 0.029 0.028 

FSV-BB 0.093 0.100 0.104 0.057 0.054 0.021 0.029 0.035 0.026 0.025 0.161 0.150 0.154 0.082 0.083 0.026 0.056 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 0.091 0.095 0.100 0.050 0.045 

FSV-BG 0.110 0.120 0.127 0.074 0.070 0.157 0.142 0.128 0.098 0.095 0.028 0.029 

FSV-BH 0.119 0.135 0.130 0.065 0.061 0.113 0.109 0.100 0.057 0.057 0.023 0.054 

FSV-BI 0.100 0.106 0.111 0.057 0.052 0.139 0.132 0.123 0.081 0.075 0.026 0.047 

FSV-BJ 0.105 0.108 0.105 0.053 0.048 0.152 0.149 0.146 0.087 0.083 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.079 0.097 0.099 0.051 0.049 0.013 0.026 0.033 0.022 0.021 0.157 0.174 0.167 0.100 0.094 0.032 0.107 

FSV-BO 0.103 0.112 0.126 0.066 0.054 0.199 0.201 0.200 0.105 0.103 0.030 0.055 

FSV-BQ 

FSV-BR 

FSV-BS 0.138 0.132 0.184 0.096 0.010
 

FSV-BT
 0.087 0.086 0.092 0.051 0.050 0.023 0.027 0.033 0.025 0.024 0.123 0.126 0.138 0.059 0.055 0.043 0.040 

FSV-BU 0.076 0.079 0.062 0.057 0.055 

FSV-BV 0.072 0.074 0.078 0.037 0.035 

FSV-BW 

FSV-BX 0.074 0.079 0.088 0.048 0.045 0.159 0.154 0.159 0.082 0.077 0.022 0.038 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 0.133 0.142 0.150 0.078 0.078
 

FSV-CI
 0.161 0.190 0.191 0.100 0.093 0.030 0.054 

FSV-CS 0.082 0.081 0.086 0.054 0.047 0.122 0.115 0.116 0.072 0.061 0.026 0.043 

FSV-CW 0.097 0.098 0.093 0.055 0.052 0.170 0.151 0.147 0.096 0.092 0.022 0.035 

FSV-CZ 

FSV-DD 

FSV-DF 

FSV-DI 0.149 0.166 0.179 0.090 0.085 

FSV-DV 

FSV-EE 

N 

Min 

Median 

Max 

SD 

CV 

Npast 

Medianpast 

SDpast 

NAV 

NAU 

17 

0.072 

0.097 

0.138 

0.017 

18 

0 

17 

0.074 

0.100 

0.142 

0.025 

25 

0 

17 

0.062 

0.104 

0.184 

0.026 

25 

23 

0.112 

0.027 

17 

0.037 

0.057 

0.096 

0.011 

19 

22 

0.055 

0.009 

17 

0.010 

0.052 

0.078 

0.006 

11 

22 

0.052 

0.008 

4 

0.013 

0.021 

0.023 

0.002 

9 

0 

4 

0.026 

0.028 

0.036 

0.003 

11 

0 

4 

0.033 

0.034 

0.045 

0.003 

10 

4 

0.040 

0.004 

4 

0.022 

0.026 

0.029 

0.002 

7 

5 

0.027 

0.007 

4 

0.021 

0.025 

0.028 

0.002 

8 

7 

0.024 

0.007 

13 

0.113 

0.157 

0.199 

0.016 

10 

0 

13 

0.109 

0.150 

0.201 

0.025 

17 

0 

13 

0.100 

0.147 

0.200 

0.029 

20 

14 

0.145 

0.042 

13 

0.057 

0.087 

0.105 

0.013 

15 

15 

0.080 

0.015 

13 

0.055 

0.083 

0.103 

0.013 

16 

15 

0.078 

0.015 

11 

0.022 

0.026 

0.043 

0.004 

16 

0 

11 

0.029 

0.047 

0.107 

0.012 

25 

0 

0.097 0.100 0.104 0.057 0.052 

0.022 0.025 0.026 0.014 0.013 

0.021 0.028 0.034 0.026 0.025 0.157 0.150 0.147 0.087 0.083 

0.029 0.027 0.029 0.017 0.016 

0.026 0.047 

0.007 0.013 

All Lab Report 
Round Robin LXI Laboratory Results 

All Results in μg/mL 

Total Lutein&Zeaxanthin Coenzyme Q10 Ubiquinol 

C6

Lab 329 330 331 332 333 329 330 331 332 333 329 330 331 332 333 329 

FSV-BA 0.192 0.220 0.252 0.126 0.119 

FSV-BB 0.187 0.206 0.228 0.123 0.128 

FSV-BC 

FSV-BD 

FSV-BE 

FSV-BF 0.180 0.191 0.195 0.115 0.112 

FSV-BG 0.167 0.155 0.140 0.112 0.105 

FSV-BH 0.136 0.163 0.170 0.087 0.085
 

FSV-BI
 0.165 0.179 0.185 0.112 0.106 

FSV-BJ 0.781 1.119 1.194 0.804 0.740 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.189 0.282 0.318 0.141 0.134 

FSV-BO 0.229 0.256 0.277 0.126 0.133 

FSV-BQ 

FSV-BR 

FSV-BS 0.191 0.229 0.256 0.119 0.102
 

FSV-BT
 0.164 0.190 0.205 0.102 0.096 

FSV-BU 0.152 0.166 0.116 0.101 0.093 

FSV-BV 0.201 0.219 0.236 0.127 0.118 

FSV-BW 0.436 0.595 1.032 0.715 0.709 0.179 0.211 0.814 0.528 0.619 0.257 

FSV-BX 0.181 0.192 0.212 0.109 0.105 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 0.238 0.265 0.293 0.152 0.149
 

FSV-CI
 0.191 0.244 0.259 0.137 0.126 0.700 0.880 1.100 0.650 0.590 

FSV-CS 0.148 0.158 0.182 0.114 0.100 

FSV-CW 0.192 0.185 0.188 0.124 0.117 0.630 0.730 0.820 0.660 0.500 

FSV-CZ 0.680 0.850 0.960 0.670 0.690 

FSV-DD 

FSV-DF 

FSV-DI 0.715 0.941 1.090 0.748 0.727 0.010 0.405 1.260 0.824 0.727 0.780 

FSV-DV 

FSV-EE 0.720 0.911 1.311 0.754 0.726 

N 17 17 17 17 17 7 7 7 7 7 2 2 2 2 2 2 

Min 0.136 0.155 0.116 0.087 0.085 0.436 0.595 0.820 0.650 0.500 0.010 0.211 0.814 0.528 0.619 0.257 

Median 0.187 0.192 0.212 0.119 0.112 0.700 0.880 1.090 0.715 0.709 0.095 0.308 1.037 0.676 0.673 0.519 

Max 0.238 0.282 0.318 0.152 0.149 0.781 1.119 1.311 0.804 0.740 0.179 0.405 1.260 0.824 0.727 0.780 

SD 0.020 0.037 0.053 0.011 0.018 0.046 0.101 0.112 0.064 0.064 

CV 11 19 25 9 16 7 11 10 9 9 

Npast 0 0 22 23 23 0 0 5 5 5 0 0 0 0 0 0 

Medianpast 0.211 0.113 0.108 1.190 0.760 0.699 

SDpast 0.056 0.017 0.018 0.060 0.169 0.162 

NAV 

NAU 

0.187 0.192 0.212 0.119 0.112 0.700 0.880 1.090 0.715 0.709 

0.039 0.040 0.053 0.025 0.023 0.070 0.101 0.112 0.072 0.071 

All Lab Report 
Round Robin LXI Laboratory Results
 

All Results in μg/mL
 

Phylloquinone (K1) x1000 25-hydroxyvitamin D 

C7

Lab 329 330 331 332 333 329 330 331 332 333 

FSV-BA 0.015 0.014 0.008 0.020 0.020 

FSV-BB 0.016 0.012 0.010 0.020 0.025 

FSV-BC 

FSV-BD 

FSV-BE 1.586 0.995 0.599 0.389 0.357 

FSV-BF 

FSV-BG 

FSV-BH 0.015 0.011 0.007 0.021 0.020 

FSV-BI 

FSV-BJ 

FSV-BK 

FSV-BL 

FSV-BM 

FSV-BN 0.017 0.011 0.008 0.019 0.018 

FSV-BO 

FSV-BQ 

FSV-BR 

FSV-BS 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW 

FSV-BX 

FSV-CC 

FSV-CE 

FSV-CF 

FSV-CG 

FSV-CI 1.339 0.887 0.530 0.402 0.308
 

FSV-CS
 

FSV-CW 

FSV-CZ 

FSV-DD 

FSV-DF 

FSV-DI 0.880 0.700 0.500 0.370 0.330
 

FSV-DV
 

FSV-EE
 

N 3 3 3 3 3 4 4 4 4 4 

Min 0.880 0.700 0.500 0.370 0.308 0.015 0.011 0.007 0.019 0.018 

Median 1.339 0.887 0.530 0.389 0.330 0.015 0.012 0.008 0.020 0.020 

Max 1.586 0.995 0.599 0.402 0.357 0.017 0.014 0.010 0.021 0.025 

SD 0.001 0.001 0.001 0.001 0.001 

CV 5 10 7 5 7 

Npast 0 0 0 0 0 0 0 0 5 4 

Medianpast 0.017 

SDpast 0.004 

NAV 

NAU 

1.339 0.887 0.530 0.389 0.330 0.015 0.012 0.008 0.020 0.020 

All Lab Report 
 

 

 

 

Round Robin LXI Laboratory Results 

All Results in μg/mL 

Analytes Reported By One Laboratory 

Analyte Code 329 330 331 332 333 

Total cis-β-Cryptoxanthin FSV-BT 0.029 0.032 0.036 0.022 0.022 

trans-α-Carotene FSV-BX 0.285 0.140 0.021 0.081 0.075 

Term 

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

Min Minimum (non-NIST) quantitative value reported 

Medianpart 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) 

NAV NIST Assigned Value

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

 = Medianpart for analytes reported by ≥ 10 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 Medianpart and MeanNIST. The expected long-term SD, eS

 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 

? Non-quantitative value: extrapolated beyond upper limit of calibration curve 

* Non-quantitative value: heterogeneous serum, damaged sample, malfunctio 

italics Not explictly reported but calculated by NIST from reported values 

Legend 

All Lab Report Page 7 / 8 

C8
 

 

 

 

 

 

 

Round Robin LXI 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-BQ 

FSV-BR 

FSV-BS 

FSV-BT 

FSV-BU 

FSV-BV 

FSV-BW
 

FSV-BX
 

FSV-CC
 

FSV-CE
 

FSV-CF
 

FSV-CG
 

FSV-CI
 

FSV-CS
 

FSV-CW
 

FSV-CZ
 

FSV-DD
 

FSV-DF
 

FSV-DI
 

FSV-DV
 

FSV-EE
 

n 

% 1
 

% 2
 

% 3
 

% 4
 

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

2 1 1 1 1 1 1 1 1
 

1 1 1 1 1 1 1 1 1 2 1
 

1
 

1 1
 

1 3 2 1
 

1 1 1 2 1 1 1 1
 

1 2 2 3 1 1 2 1 2 1
 

2 2 2 1 1 1 1 1 2 1 2
 

2 1 1 1 1 1 1 1 1 1
 

1 2 1 1 1 1 1 1
 

2 1
 

1 1
 

1 1
 

2 1 2 1 1 1 1 1 1 4 2
 

1 2 1 2 1 1 2 1 2 1 2
 

2 2
 

1 2
 

2 1 2 1 2 3 1 3 1
 

2 1 2 1 1 1 1 1 2 2 1
 

3 2 2 2 1 2 1 2
 

2 1 1 1 1 1 2 1
 

1 1 4 1 1 2
 

1 1 1 1 1 1 1 1 1 1
 

1 1
 

2 3 4
 

1 2
 

1 1 1 1 1 1 1 2 2
 

1 1 1 1 1 4 2 1 1
 

2 1 2 1 1 1 1 2 1 1
 

2 1 2 1 1 1 1 1 1 1
 

1 1 3
 

3
 

2
 

1 1 1 1 4 1 1
 

2 2
 

2 2
 

36 33 21 23 11 20 17 17 13 11 17
 

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

53 64 52 74 91 85 82 76 62 64 71
 

42 30 43 13 9 0 18 18 38 27 29
 

6 6 0 9 0 5 0 6 0 0 0
 

0 0 5 4 0 10 0 0 0 9 0
 

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  You i − Median i 

2
 

AP = Apparent Precision = ∑

yo u 



 

 (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 8 / 8
 

C9
 

 

 

 

Appendix D. Representative “Individualized Report” for RR61 

Each participant in RR61 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 RR61: 

• Total Retinol 

• trans-Retinol 

• Retinyl Palmitate 

• α-Tocopherol 

• γ/β-Tocopherol 

• δ-Tocopherol 

• 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 14 pages are the “Individualized Report” for the analytes evaluated by 

participant FSV-BA. 

D1
 

Set 1 of 32 

Individualized Round Robin LXI Report: FSV-BA 

Summary 

Serum 329 Serum 330 Serum 331 Serum 332 

D2

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

Total Retinol 0.559 0.520 32 0.433 0.399 32 0.326 0.304 32 0.697 0.646 

Retinyl Palmitate 0.07 0.06 10 0.1 0.0 9 0.1 0.0 9 0.12 0.10 

α-Tocopherol 24.43 23.69 33 15.75 15.39 33 8.66 8.50 33 10.59 10.50 

γ/β-Tocopherol 1.061 0.902 21 2.569 2.430 21 3.829 3.710 21 1.935 1.819 

δ-Tocopherol 0.065 0.058 6 0.065 0.073 6 0.079 0.100 6 0.064 0.072 

Total β-Carotene 0.580 0.548 19 0.351 0.337 19 0.158 0.145 19 0.132 0.130 

trans-β-Carotene 0.548 0.507 11 0.330 0.309 11 0.148 0.141 11 0.126 0.126 

Total cis-β-Carotene 0.033 0.033 7 0.021 0.021 7 0.010 0.010 6 0.006 0.007 

Total α-Carotene 0.316 0.316 19 0.154 0.151 19 0.016 0.016 19 0.084 0.087 

Total Lycopene 0.262 0.269 17 0.427 0.445 17 0.577 0.583 17 0.507 0.537 

trans-Lycopene 0.121 0.100 7 0.231 0.223 7 0.327 0.290 7 0.300 0.274 

Total β-Cryptoxanthin 0.105 0.097 17 0.121 0.100 17 0.128 0.104 17 0.067 0.057 

Total α-Cryptoxanthin 0.021 0.021 4 0.036 0.028 4 0.045 0.034 4 0.029 0.026 

Total Lutein&Zeaxanthin 0.192 0.187 17 0.220 0.192 17 0.252 0.212 17 0.126 0.119 

25-hydroxyvitamin D 0.015 0.015 4 0.014 0.012 4 0.008 0.008 4 0.020 0.020 

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 

100 Bureau Drive Stop 8392 

Gaithersburg, MD 20899-8392 USA Ema

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

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

Total Retinol 

[Analyte], μg/mL

Your [Analyte], μg/mL

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 2 / 14 

D3
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

Retinyl Palmitate 

[Analyte], μg/mL Apparent Precision, SD 

329330331326292301313323332290300312322333 

Your [Analyte], μg/mL

Apparent Precision, SD 

Median [Analyte], μg/mL 

Concordance, SD Long-term Precision, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 3 / 14 

D4
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

α-Tocopherol 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 4 / 14 

D5
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

γ/β-Tocopherol 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 5 / 14 

D6
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

δ-Tocopherol 

[Analyte], μg/mL

Your [Analyte], μg/mL

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 6 / 14 

D7
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

Total β-Carotene 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 7 / 14 

D8
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

trans-β-Carotene 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 8 / 14 

D9
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

Total α-Carotene 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 9 / 14 

D10
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

Total Lycopene 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 10 / 14 

D11
For details of the construction and interpretation of these plots, see:

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

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

trans-Lycopene 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 11 / 14 

D12
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.

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

Total β-Cryptoxanthin 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 12 / 14 

D13
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.

NIST, this RR

 

Set 1 of 32 

Individualized RR LXI Report: FSV-BA 

Total Lutein&Zeaxanthin 

[Analyte], μg/mL

Your [Analyte], μg/mL

Median [Analyte], μg/mL 

Apparent Precision, SD 

329330331326292301313323332290300312322333 

Apparent Precision, SD 

Long-term Precision, SD Concordance, SD 

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

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

1st Quartile (25%) Expectation 

Serum History Comments 

#329 Fresh frozen: New Native, single-source 

#330 Fresh frozen: New 15:16 blend of #329 and #331 

#331 Fresh frozen: 60:#326 Native, single-source 

#332 Fresh-frozen: 53:#292, 55:#301, 57:#313, 59:#323 Native, same single-source as #333 

#333 Lyophilized: 53:#290, 55:#300, 57:#312, 59:#322 Native, same single-source as #332 

Individualized Report Page 13 / 14 

D14
Set 1 of 32 

Individualized Round Robin LXI Report: FSV-BA
 

Graphical Comparability Summary
 

Total Retinol α-Tocopherol Total β-Carotene Tot

D15

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

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

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

Individualized Report 
 

 

 

Appendix E. Shipping Package Inserts for RR26 

The following five items were included in each package shipped to an RR26 participant: 

•	 Cover letter 

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

Material
	

•	 Preparation and Validation of Ascorbic Acid Solid Control Material Datasheet 

•	 Analysis of Control Materials and Test Samples Datasheet 

•	 Packing List and Shipment Receipt Confirmation Form 

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

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

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

E1
November 8, 2006 

Dear Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute of Standards and Technology 

Gaithersburg, Maryland 20899-

The samples within this package constitute the first Vitamin C Round Robin (RR26) of the fiscal year (FY) 07 

Micronutrients Measurement Quality Assurance Program. RR26 consists of four vials of frozen serum test 

samples(# 13, #42, #I I 2, and # 113), one vial of ascorbic acid solid control material, and one vial of SRM 970 

Ascorbic Acid in Serum-Level I to be used as the serum control material. Please follow 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 SRM 970 to validate the performance of your measurement system before you analyze the test 

samples. The target value and ::::95% confidence interval for SRM 970-Level I is 8.41 ± 0.61 μmol/L of 

sample. 

Please be aware that sample contact with any oxidant-contaminated surface (vials, glassware, etc.) may degrade 

your measurement system's perfonnance (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, 

The report for RR25 was mailed mid-October. If you find your results for _RIUS 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). 

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 the RR26 samples by March 5, 2007. We would appreciate receiving 

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

confidential. 

Brown Thomas 

ese ch Chemist 

ytical Chemistry Division 

Chemical Science and Technology Laboratory 

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

RR26 Report Form for Ascorbic Acid Solid Control Material Preparation 

RR26 Report Form for Control Material and Test Sample Analyses 

N•Si 

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 = 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 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 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 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: 301-

975-3120 or Jeanice.BrownThomas@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 26 

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 by March 5, 2007 

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 26 

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 SRM 970-Level I 

Target: 8.41 ±0.61 μmol/L 

Serum Test Sample #13 μmol/L of Sample 

Serum Test Sample #42 μmol/L of Sample 

Serum Test Sample #112 μmol/L of Sample 

Serum Test Sample #113 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 by March 5, 2007 

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 26
 

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 #13 Liquid frozen (1:1 serum:10% MPA) 

VitC #42 Liquid frozen (1:1 serum:10% MPA) 

VitC #112 Liquid frozen (1:1 serum:10% MPA) 

VitC #113 Liquid frozen (1:1 serum:10% MPA) 

SRM 970 Lv1 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 RR26 

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
April 26, 2007 

Dear _Colleague: 

UNITED STATES DEPARTMENT OF COMMERCE 

National Institute Df Standards and Technology 

Gaithersburg, Maryland 20899-

Enclosed is the summary report of the results for Round Robin 26 (RR 26) 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 

1 OOxMADe/median. 

RR 26 consisted of four test samples ( 13, 4 2, 112, and 113 ), one serum control material, 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 laboratory'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 second vitamin C round robin (RR 27) of the 2007 M2

QAP will be shipped 

during the week of June 4, 2007. 

We look forward to meeting with you at the Micronutrients Measurement Quality Assurance 

Workshop that is being held in conjunction with the Experimental Biology meeting on May 2, 

2007 at the Convention Center in Washington, DC. 

Enclosures 

Cc: L. C. Sander 

D.L. Duewer 

egarding this report, please contact David Duewer at 

r@nist.gov or me at 301-975-3120; e-mail: 

7-0685. 

NISI 

F2
 

 

 

 

 

 

 

 

 

The NIST M2QAP Vitamin C Round Robin 26 (RR26) 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 RR26 sample measurements. 

Page “All Lab” Report 

1 A tabulation of results and summary statistics for Total Ascorbic Acid [TAA] in the RR26 

samples and control/calibration solutions. 

Serum-based Samples. One serum control and four unknowns were distributed in RR26. 

Control 1 SRM 970 level 1, ampouled in mid-1998. 

Sample 1 Serum 13, ampouled in late 2001, previously distributed as sample S19:1 (RR19, Fall 

03), S21:1 (RR21, Fall 04) and S23:1 (RR23, Fall 05). A “blank” stripped serum. 

Sample 2 Serum 42, ampouled in late 2001, previously distributed as sample S18:2 (RR18, Spring 

03), S19:3 (RR19, Fall 03), S21:3 (RR21, Fall 04), S22:3 (RR22, Spring 05) and S24:2 

(RR24, Spring 06). 

Sample 3 Serum 112, ampouled in 1993, previously distributed as sample 179B in RR4 (1993). 

Sample 4 Serum 113, ampouled in 1993, previously distributed as sample 180 in RR4 (1993), RR6 

(1994) and RR14 (2001). 

Results. 

1)		 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 g/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). 

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

close to 0.0, slopes close to 1.0, R2

 close to 1, and RMS close to 0.0), the measurement systems for 

all participants are linear and reasonably well calibrated. However, several participants continue to 

have measurement systems that perform somewhat differently for the control solutions and the test 

samples. 

3)		 Somewhat remarkably, the median and the MADe for sera 112 (S26:3) and 113 (S26:4) are 

effectively unchanged from the TAA results obtained for these materials in the 1993 RR4 study. 

F3
 

 

 

Appendix G. “All-Lab Report” for RR26 

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" 26 - March 2007
 

Control / Calibration Samples MPA Dilute Solution 1 Sam

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#1 S26:1 S26:2 S26:3 S26:4 

VC-MA 20/03/07 58.7 29.3 14.3 58.8 29.7 14.8 0.0 0.27 1.00 1.000 0.3 1.033 244. 0.5734 554.3 8.5 0.0 35.2 79.8 21.3 

VC-MB 26/11/06 57.1 28.3 14.1 59.4 28.9 13.9 0.0 -0.39 1.04 1.000 0.4 1.027 244. 0.5630 560.2 8.3 0.0 33.0 71.0 19.4 

VC-MC 23/01/07 55.6 28.2 14.2 60.7 27.0 14.0 0.0 -1.34 1.09 0.995 2.2 1.029 243. 0.5507 562.3 8.7 0.0 33.7 57.2 15.1 

VC-ME 07/03/07 58.9 29.6 14.6 57.7 29.6 14.6 0.0 0.20 0.98 1.000 0.3 1.028 243. 0.5843 563.5 9.1 0.5 32.3 68.1 21.0 

VC-MG 26/01/07 58.7 29.5 15.0 58.1 27.6 12.5 0.0 -1.24 1.00 0.998 1.4 1.029 243.6 0.5910 571.8 9.4 0.0 35.8 82.7 23.8 

VC-MH 20/02/07 61.4 30.9 15.0 62.7 31.0 16.7 0.0 0.44 1.01 0.999 1.0 1.032 244. 0.6130 566.6 8.5 0.6 32.9 67.0 19.2 

VC-MI 21/02/07 55.2 27.5 13.9 55.2 27.7 14.1 0.0 0.10 1.00 1.000 0.1 1.031 8.0 0.0 33.0 71.3 22.4 

VC-MJ 05/02/07 59.7 29.9 15.5 62.1 32.4 16.1 0.0 0.24 1.04 0.999 0.8 1.025 254 a 0.369 a 350.9 a 11.9 4.1 36.5 83.2 27.8 

VC-MK 28/02/07 59.6 30.1 15.3 58.9 31.0 17.3 2.8 2.81 0.94 1.000 0.1 1.030 244. 0.5948 566.6 10.5 3.5 35.7 82.0 26.1 

VC-MN 23/03/07 58.7 29.3 14.1 60.7 30.4 15.1 -1.1 -0.47 1.05 0.999 0.8 1.029 243.8 0.5616 543.3 8.9 0.0 34.1 75.9 23.0 

VC-MU 02/03/07 61.6 31.0 17.6 59.1 30.1 17.0 0.0 0.13 0.96 1.000 0.2 1.034 244. 0.5881 542.0 7.7 0.3 29.0 68.7 20.2 

11 11 11 11 11 11 11 11 9 9 9 11 11 11 11 11 

58.7 29.4 14.9 59.4 29.6 15.1 0.2 1.030 243.7 0.5800 558.9 9.0 0.8 33.7 73.4 21.8 

2.1 1.1 1.0 2.1 1.6 1.5 1.0 0.003 0.4 0.0195 10.4 1.2 1.5 2.1 8.2 3.5 

55.2 27.55 13.9 55.2 27.02 12.5 -1.1 1.025 243.0 0.5507 542.0 7.7 0.0 29.0 57.2 15.1 

57.9 28.76 14.2 58.5 28.28 14.0 0.0 1.028 243.6 0.5630 554.3 8.4 0.0 32.9 68.4 19.8 

58.7 29.51 14.6 59.1 29.72 14.8 0.0 1.029 244.0 0.5843 562.3 8.7 0.0 33.7 71.3 21.3 

59.7 29.95 15.2 60.7 30.68 16.4 0.0 1.031 244.0 0.5910 566.6 9.3 0.5 35.4 80.9 23.4 

61.6 31.02 17.6 62.7 32.37 17.3 2.8 1.034 244.0 0.6130 571.8 11.9 4.1 36.5 83.2 27.8 

1.4 0.8 0.8 1.9 1.8 1.3 0.0 0.003 0 0.0162 6.4 0.7 0.0 2.1 6.8 2.9 

2 3 5 3 6 9 0.26 0.00 2.8 1.1 8 6 10 14 

MADe eSD 

CV CV 

Median Median 

%75 %75 

Max Max 

Min Min 

%25 %25 

N N 

Average Average 

SD SD 

Gravimetric, μmol/L Measured, μmol/L Calibration Parameters Spectrophotometry Measured, μmol/L 

a) 5% Trichloroacetic acid solution 

All Lab report 
Appendix H. Representative “Individualized Report” for RR26 

Each participant in RR26 received an “Individualized Report” reflecting their reported 

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

“VC-MA”. 

H1
 

Set 1 of 11 

Vitamin C "Round Robin" 26 Report: Participant VC-MA
 

MPA Dilute Solution 1 Control/Calibration Solutions 

Density Spectrophotometry Ymeas = Inter + Slope* Xgrav 

Date RR Method 

09/13/04 21 HPLC-EC 

03/08/05 22 HPLC-EC 

10/17/05 23 HPLC-EC 

03/09/06 24 HPLC-EC 

08/28/06 25 HPLC-EC 

03/20/07 26 HPLC-EC 

g/mL 

1.030 

1.034 

1.030 

1.031 

1.039 

1.033 

λmax Amax E1% 

244.0 0.555 562.2 

243.0 0.559 562.9 

244.0 0.562 567.9 

244.0 0.568 586.7 

242.0 0.555 557.4 

244.0 0.573 554.3 

Inter Slope R2 SEE 

-0.1 0.99 1.000 0.10 

0.2 1.06 1.000 0.24 

-0.6 1.09 0.998 1.47 

0.2 1.13 1.000 0.41 

0.8 0.95 0.999 0.92 

0.3 1.00 1.000 0.31 

Mean 1.033 243.5 0.56 565.2 0.57 

SD 0.003 0.8 0.01 11.5 0.52 

CV 0.34 0.34 1.3 2.0 

[TAA] mmol/Lsample 

2 0.0 0.0 0.0 

6 35.1 0.3 1.1 

2 72.1 0.1 10.8 

4 19.7 0.4 1.3 

Date RR Sample 

09/13/04 21 CS#1 

03/08/05 22 CS#1 

10/17/05 23 CS#1 

10/17/05 23 CS#1 

03/09/06 24 CS#1 

08/28/06 25 CS#1 

03/20/07 26 CS#1 

11/13/03 19 S19:1 

09/13/04 21 S21:1 

10/17/05 23 S23:1 

03/20/07 26 S26:1 

03/20/03 18 S18:2 

11/13/03 19 S19:3 

09/13/04 21 S21:3 

03/08/05 22 S22:3 

03/09/06 24 S24:2 

03/20/07 26 S26:2 

09/16/93 04 S04:2 

03/20/07 26 S26:3 

09/16/93 04 S04:3 

05/25/95 06 S06:2 

09/27/01 14 S14:1 

03/20/07 26 S26:4 

Rep1 Rep2 Fadj Mean SDdup 

8.1 7.9 1.0 8.0 0.1 

8.5 8.7 1.0 8.6 0.1 

9.3 9.5 1.0 9.4 0.1 

9.3 9.5 1.0 9.4 0.1 

9.3 9.2 1.0 9.3 0.0 

8.3 8.6 1.0 8.4 0.2 

8.6 8.3 1.0 8.5 0.2 

N Mean SDrepeat SDreprod 

7 8.8 0.1 0.6 

nd nd 1.0 

nd nd 1.0 

0.0 0.0 1.0 0.0 0.0 

0.0 0.0 1.0 0.0 0.0 

35.1 36.0 1.0 35.6 0.6 

35.9 35.8 1.0 35.9 0.1 

33.2 32.9 1.0 33.0 0.2 

35.7 35.6 1.0 35.6 0.1 

35.8 35.5 1.0 35.6 0.2 

35.0 35.4 1.0 35.2 0.3 

2.27 2.27 28.4 64.4 0.0 

79.7 79.8 1.0 79.8 0.1 

0.66 0.64 28.4 18.4 0.3 

0.7 0.7 28.4 19.2 0.2 

20.4 19.6 1.0 20.0 0.6 

21.1 21.5 1.0 21.3 0.3 

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

Micronutrients Measurement Quality Assurance Program 

National Institute of Standards and Technology 

100 Bureau Drive Stop 8392 Fax: (301) 977-0685 

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

Individualized Report Page 1/2 

H2
 

 

 NIST, RR 22

Set 1 of 11 

Vitamin C "Round Robin" 26 Report: Participant VC-MA 

Total Ascorbic Acid 

[Total Ascorbic Acid], μmol/L 

Your [Total Ascorbic Acid], μmol/L

S18:2S19:3S21:3S22:3S24:2 Apparent Precision, SD S26:2S04:2S26:3S04:3S06:2S14:1S26:4 

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 

S26:1 VitC #13, a "blank" previously distributed in RRs 16, 19, 21, 22, and 24 

S26:2 VitC #42, previously distributed in RRs 18, 19, 21, 22, and 24 

S26:3 VitC #112, previous distributed in RR 4 

S26:4 VitC #113, previous distributed in RR 4, 6 and 14 

Individualized Report Page 2 / 2 

H3