NISTIR 7880-44 

NIST Micronutrients Measurement

Quality Assurance Program

Summer 2014 

Comparability Studies

Results for Round Robin LXXVI

Fat-Soluble Vitamins and Carotenoids in Human Serum 

and Round Robin 41 Ascorbic Acid in Human Serum

David L. Duewer

Jeanice B. Thomas

http://dx.doi.org/10.6028/NIST.IR.7880-44

184319327407358364374386399408383390409385396411384410

[Total Retinol], μg/mL

FSV RR LXXVI

RR34RR36

RR36RR38RR40RR41

RR32RR35RR36RR38RR41RR32RR33RR35

RR38RR40RR41

RR11RR12RR13RR14RR15RR16RR19RR20RR23RR25

RR29RR31RR34RR37

RR39RR41

[Total Ascorbic Acid], μmol/L

VC RR 41
NISTIR 7880-44

NIST Micronutrients Measurement

Quality Assurance Program

Summer 2014 

Comparability Studies

Results for Round Robin LXXVI

Fat-Soluble Vitamins and Carotenoids in Human Serum

and Round Robin 41 Ascorbic Acid in Human Serum

David L. Duewer

Jeanice B. Thomas

Chemical Sciences Division

Materials Measurement Laboratory 

http://dx.doi.org/10.6028/NIST.IR.7880-44 

June 2015 

U.S. Department of Commerce 

Penny Pritzker, Secretary

National Institute of Standards and Technology 

Willie E. May, 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 2014 MMQAP measurement comparability improvement studies: 1) Round Robin LXXVI

Fat-Soluble Vitamins and Carotenoids in Human Serum and 2) Round Robin 41 Total Ascorbic Acid 

in Human Serum. To avoid increasing participation fees, the overhead costs for these programs 

were minimized by shipping the materials in January 2014 together with the samples for FSV Round 

Robin LXXV and VC Round Robin 40. Participants were requested not to analyze any of the 

Summer samples before June 1, 2014 but to provide their measurement results by September 15, 

2014. Participants were reminded of the due-date by e-mail on August 4, 2014. 

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

Round Robin 41: Vitamin C in Human Serum ............................................................................... 2

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

Appendix A. Shipping Package Inserts for RR76 ........................................................................ A1

Appendix B. Final Report for RR76 .............................................................................................. B1 

Appendix C. All-Lab Report for RR76 .......................................................................................... C1

Appendix D. Representative Individualized Report for RR76 ................................................... D1

Appendix E. Shipping Package Inserts for RR41 ......................................................................... E1

Appendix F. Final Report for RR41 ............................................................................................... F1

Appendix G. “All-Lab Report” for RR41..................................................................................... G1

Appendix H. Representative “Individualized Report” for RR41 ............................................... 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 LXXVI: Fat-Soluble Vitamins and Carotenoids in Human Serum

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

LXXVI comparability study (hereafter referred to as RR76) received one lyophilized and four 

liquid-frozen human serum test samples for analysis. Unless multiple vials were previously 

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

participants in January 2014 in the same shipping package as the RR75 materials but in separate 

clearly labeled plastic bags. Participants were requested not to analyze any of the RR76 samples 

before June 1, 2014 but to provide their measurement results by September 15, 2014. 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 RR76 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 

1 
numerical “score card” for each participant’s measurement comparability for the more 

commonly reported analytes. This All-Lab Report is reproduced as Appendix C. 

• 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 the Individualized Report 

are described in detail elsewhere [3]. An example Individualized Report is reproduced as 

Appendix D. 

Round Robin 41: Vitamin C in Human Serum

Participants in the MMQAP Vitamin C in Human Serum Round Robin 40 comparability study 

(hereafter referred to as RR41) received four frozen serum test samples and two frozen control sera. 

Unless multiple vials were previously requested, participants received one vial of each material. 

These materials were shipped on dry ice to participants in January 2014 in the same shipping 

package as the RR40 materials but in separate clearly labeled plastic bags. Participants were 

requested not to analyze any of the RR41 samples before June 1, 2014 but to provide their 

measurement results by September 15, 2014. 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). 

The final report delivered to every participant in RR41 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 All-Lab 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 the Individualized 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 RR76 

The following items were included in each package shipped to an RR76 participant:

• Combined cover letter for Round Robin LXXV (RR75) and RR76.

See Appendix A in NISTIR-43. 

• Datasheet for RR76. This was enclosed in the same sealed waterproof bag that

contained the cover letter and the data sheet for RR75. 

• Packing List and Shipment Receipt Confirmation Form for RR76.

This RR76 samples were enclosed in a bubble-wrapped sealed plastic bag that was 

labeled:

The packing list was placed at the top of the shipping box, between the cardboard 

covering and the foam insulation. 

NIST MMQAP-FSV: RR LXXVI

Micronutrients Measurement Fat-Soluble 

Vitamin

Quality Assurance Program

Summer 2014 Samples

Analyze after: June 1, 2014

Results due on or before:

September 15, 2014

A1 
Participant #: ________ Date: _____________

Mail: M2QAP

 NIST, Stop 8392

 Gaithersburg, MD 20899-8392

Please return results by

15-Sep-2014

Fax: 301-977-0685

Email: David.Duewer@NIST.gov

Analyte 407 408 409 410 411 Units*

total retinol

trans-retinol

retinyl palmitate

α-tocopherol

γ/β-tocopherol

δ-tocopherol

total β-carotene

trans-β-carotene

total cis-β-carotene

total α-carotene

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

Phytoene

Phytofluene

* we prefer μg/mL

Were the samples frozen when received? Yes | No

Comments:

Round Robin LXXVI: Human Sera

NIST Micronutrients Measurement Quality Assurance Program

A2
Participant #: ________ Date: _____________

Mail: M2QAP

 NIST, Stop 8392

 Gaithersburg, MD 20899-8392

Fax: 301-977-0685

Email: David.Duewer@NIST.gov

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

Serum Form Reconstitute? Vial/Cap

#407 Lyophilized Yes 5 mL clear / silver

#408 Liquid frozen No 3 mL amber / blue

#409 Liquid frozen No 2 mL amber / gold

#410 Liquid frozen No 2 mL amber / purple

#411 Liquid frozen No 2 mL clear / black

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) Email (david.duewer@nist.gov) or fax (301-977-0685) us the

following information:

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 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

Packing List and Shipment Receipt Confirmation Form

NIST Micronutrients Measurement Quality Assurance Program

Fat-Soluble Vitamins Round Robin LXXVI

A3
Appendix B. Final Report for RR76 

The following three pages are the final report for RR76 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 3, 2014 

Dear Colleague:

Enclosed is the summary report of the results for Round Robin LXXVI (RR76) of the 2014 NIST 

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

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

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

graphical summary of your measurement comparability. RR76 (Sera 407 - 411) consisted of one vial of 

lyophilized serum and one vial each of four liquid-frozen serum samples. Details regarding the samples 

can be found in the enclosed report.

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

Lab Report. Combined 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 graphically in the “target plots” that are the last page of your Individualized Report. If you 

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

If you returned your intent-to-participate form for the 2015 MMQAP, you should have received a 

confirmation receipt. Please notify us if you have not received your confirmation receipt.

Laboratories participating in the upcoming program will receive samples for the two fat-soluble vitamins 

and carotenoids in serum studies (RR LXXVII and LXXVIII) in February 2015. Please note that we will 

ship the samples for both studies at the same time in February. Results will be due in May 2015 for the 

first study and in September 2015 for the second study. We will send you a reminder in late July 2015 

about the reporting deadline for the second study. Please contact us immediately if this schedule is 

problematic for your laboratory. 

If you have questions or concerns regarding this report, please contact David Duewer at 301-976-3935; 

e-mail: david.duewer@nist.gov or me at 301-976-3120; e-mail: jbthomas@nist.gov; or fax: 

301-977-0685. 

Sincerely,

Jeanice Brown Thomas, M.B.A. David L. Duewer, Ph.D. 

Research Chemist Research Chemometrician 

Chemical Sciences Division Chemical Sciences Division

Material Measurement Laboratory Material Measurement Laboratory 

Enclosures 

UNITED STATES DEPARTMENT OF COMMERCE

National Institute of Standards and Technology

Gaithersburg, Maryland 20899-8390

B2
The NIST MMQAP Round Robin LXXVI (RR76) report consists of:

Page All-Lab Report

1-4 A listing of all results and statistics for analytes reported by more than one participant.

5 The legend for the list of results and statistics.

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

Page Individualized Report

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

2 to 

n

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

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

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

Samples. Five samples were distributed to each participant in RR76. 

Serum Description Prior Distributions

407 Lyophilized, native, single-source, prepared in 1992. #184:RR28-6/93, #319:RR59-3/96;

#327:RR60-9/96 

408 Fresh-frozen, native, multi-donor, prepared in 2009. 

This is Level II of SRM 968e. 

#358:RR66-9/09, #364:RR67-3/10, 

#374:RR69-3/11, #386:RR71-3/12; 

#399:RR74-9/13 

409 Fresh-frozen, native, single donor, prepared in 2011 #383:RR71-3/12;#390:RR72-9/12 

410 Fresh-frozen, native, single donor, prepared in 2011 #384:RR71-3/12 

411 Fresh-frozen, two donor, prepared in 2011. All analytes 

in this material are expected to be about half-way 

between those for sera 409 and 410. 

#385:RR71-3/12;#396:RR73-3/13 

Results

1) Stability: There have been no appreciable changes in either the level nor the variability in any

analytes in the 22-year old lyophilized serum 407, the five-year old fresh-frozen SRM 968e serum

408, or the three-year old fresh-frozen sera 409, 410, and 411.

2) Linear additivity: Serum 411 was prepared as a 31:26 blend of the serum pools used to prepare sera

409 and 410. Assuming that the concentration of an analyte in the blend is the simple sum of the

concentrations in the individual pools, the result for any analyte in the blended material is expected to

be the weighted average of the results in the parent materials: Serum 411 = ((31 × #409) + (26 ×

Serum 410))/57.

Figure 1 plots values calculated from the sera 409 and 410 medians as a function of the medians of

the serum 411 measurements. The measured and calculated values agree very well.

Therefore, if the result for any analyte in serum 411 is much different from the average of sera 409

and 410 results, you may want to carefully re-evaluate your measurement procedure for that analyte.

Summary Report B3 1 / 2 
Figure 1: Measured vs Calculated Medians for the Blended Serum 411 

The solid blue circles represent the {Measured, Calculated} median values for all RR76 analytes reported by at least 

five participants. The red line represents the ideal relationship: Estimated = Measured. The blue error-bars 

represent approximate 95 % confidence intervals on the medians, Median ± tt95%,nn−1 × eSD⁄√nn, 

where n is the number of participants reporting quantitative values for the analyte, 

eSD is estimated from the median absolute deviation from the median, and

t95%,n-1 is the Student t 95 % confidence expansion factor.

RP

TaC

TZ

t-bC TbC

TL

TbX

TL&Z

t-L

TL

TR

CoQ10

g/bT

aT

0.01

0.1

1

10

0.01 0.1 1 10

Calculated Medians, μg/mL

Measured Median Values for Serum #411, μg/mL

Summary Report B4 2 / 2 
Appendix C. “All-Lab Report” for RR76 

The following six pages are the “All-Lab Report” for RR76 as provided to all 

participants, with two exceptions: 

• the participant identifiers (Lab) have been altered and

• 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. 

C1 
Round Robin LXXVI Laboratory Results

All Lab Report 

Lab 407 408 409 410 411 407 408 409 410 411 407 408 409 410 411 407 408 409 41

FSV-BB 0.342 0.477 0.444 0.452 0.438 0.096 0.076 0.030 0.033 0.030 4.62 10.63 7.26 8.2

FSV-BC 0.339 0.491 0.428 0.432 0.441

FSV-BD 0.369 0.539 0.486 0.491 0.505 4.30 10.90 7.50 8.4

FSV-BE 0.390 0.580 0.530 0.550 0.530 4.20 11.40 7.40 9.0

FSV-BFa 0.350 0.460 0.450 0.450 0.420 3.70 9.30 5.80 7.2

FSV-BG 0.362 0.496 0.459 0.465 0.462 0.122 0.030 0.015 0.022 0.018 4.47 10.37 6.94 8.0

FSV-BH 0.272 0.442 0.346 0.356 0.365 4.22 11.13 6.93 8.5

FSV-BJ 0.351 0.498 0.468 0.464 0.468 4.33 10.53 6.82 8.6

FSV-BK 0.348 0.489 0.444 0.451 0.454 4.36 10.11 6.72 7.8

FSV-BL 0.340 0.490 0.430 0.400 0.430 3.90 9.50 6.50 7.3

FSV-BM 0.340 0.480 0.480 0.440 0.450 3.90 9.00 6.40 7.4

FSV-BN 0.377 0.533 0.481 0.489 0.495 4.55 10.43 7.05 7.8

FSV-BO 0.330 0.500 0.460 0.460 0.460 4.29 10.29 7.27 7.7

FSV-BR 0.300 0.525 0.390 0.475 0.473 4.53 11.58 7.13 9.5

FSV-BS 0.345 0.499 0.471 0.483 0.467 0.345 0.499 0.471 0.483 0.467

FSV-BT 0.389 0.524 0.450 na 0.595 4.55 10.26 7.62 na 

FSV-BU 0.275 0.511 0.379 0.363 0.472 4.90 10.48 8.28 9.3

FSV-BV 0.405 0.491 0.519 0.380 0.471 5.72 11.63 8.64 8.2

FSV-BW 0.570 0.500 0.500 0.520 0.430 0.072 0.016 0.009 0.004 0.006 4.34 10.75 6.94 8.5

FSV-CD 0.360 0.510 0.460 0.460 0.480 4.63 10.35 7.42 7.9

FSV-CE 0.351 0.559 0.457 0.467 0.457 3.58 13.14 7.08 8.3

FSV-CG 0.313 0.425 0.397 0.387 0.393 3.35 8.16 5.38 6.

FSV-CI 0.312 0.458 0.342 0.377 0.410 0.087 0.019 0.014 0.017 0.008 3.98 9.25 6.42 7.0

FSV-CO 4.31 10.23 6.84 8.2

FSV-CZ 0.430 0.606 0.568 0.511 0.553 4.50 9.01 5.88 7.2

FSV-DD 0.340 0.500 0.400 0.420 0.430

FSV-DV 0.347 0.468 0.431 0.440 0.438 3.40 8.80 5.80 7.4

FSV-EE

FSV-FK 0.368 0.450 0.439 0.445 0.410 3.90 9.70 5.30 7.0

FSV-FZ ≥0.342 ≥0.451 ≥0.447 ≥0.455 ≥0.463 0.342 0.451 0.447 0.455 0.463 0.059 0.045 0.017 0.023 0.022 4.42 9.84 6.91 8.2

FSV-GD 0.343 0.496 0.454 0.449 0.454 4.24 10.41 6.83 8.0

FSV-GE 0.493 0.685 0.670 0.564 0.687 12.37 33.53 23.61 21.6

N 29 29 29 28 29 2 2 2 2 2 5 5 5 5 5 28 28 28 2

Min 0.272 0.425 0.342 0.356 0.365 0.342 0.451 0.447 0.455 0.463 0.059 0.016 0.009 0.004 0.006 3.35 8.16 5.30 6.

Median 0.348 0.498 0.454 0.451 0.457 0.344 0.475 0.459 0.469 0.465 0.087 0.030 0.015 0.022 0.018 4.32 10.36 6.94 8.0

Max 0.570 0.685 0.670 0.564 0.687 0.345 0.499 0.471 0.483 0.467 0.122 0.076 0.030 0.033 0.030 12.37 33.53 23.61 21.6

eSD 0.027 0.031 0.039 0.041 0.034 0.022 0.021 0.003 0.007 0.015 0.34 0.89 0.67 0.8

eCV 8 6 8 9 7 26 70 20 32 82 8 9 10 

Npast 36 31 29 31 31 8 8 0 0 0 10 7 5 6 6 38 30 27 2

Medianpast 0.366 0.507 0.462 0.470 0.474 0.409 0.481 0.126 0.027 0.016 0.019 0.015 4.33 10.31 7.02 8.0

SDpast 0.031 0.041 0.029 0.034 0.035 0.030 0.050 0.034 0.009 0.009 0.012 0.011 0.29 0.77 0.63 0.6

NAV 0.348 0.497 0.452 0.451 0.456 0.348 0.497 0.452 0.451 0.456 0.087 0.030 0.015 0.022 0.018 4.31 10.35 6.93 8.0

NAU 0.029 0.040 0.037 0.041 0.037 0.029 0.040 0.037 0.041 0.037 0.023 0.021 0.011 0.012 0.015 0.45 0.82 0.64 0.8

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

C2
Round Robin LXXVI Laboratory Results

All Lab Report 

Lab

FSV-BB

FSV-BC

FSV-BD

FSV-BE

FSV-BFa

FSV-BG

FSV-BH

FSV-BJ

FSV-BK

FSV-BL

FSV-BM

FSV-BN

FSV-BO

FSV-BR

FSV-BS

FSV-BT

FSV-BU

FSV-BV

FSV-BW

FSV-CD

FSV-CE

FSV-CG

FSV-CI

FSV-CO

FSV-CZ

FSV-DD

FSV-DV

FSV-EE

FSV-FK

FSV-FZ

FSV-GD

FSV-GE

N

Min

Median

Max

eSD

eCV

Npast

Medianpast

SDpast

NAV

NAU

407 408 409 410 411 407 408 409 410 411 407 408 409 410 411 407 408 409 410 411 

0.044 0.083 0.065 0.083 0.049 0.320 0.242 0.042 0.055 0.050 0.304 0.231 0.040 0.054 0.047 0.017 0.011 0.002 0.001 0.003 

0.300 0.250 0.050 0.060 0.050

0.346 0.268 0.054 0.066 0.062 

0.288 0.234 0.034 0.045 0.036 

0.322 0.233 0.039 0.063 0.050 

0.313 0.248 0.043 0.062 0.049 

0.269 0.203 0.038 0.048 0.041 

0.416 0.193 0.105 0.126 0.118 0.416 0.193 0.105 0.126 0.118 nd nd nd nd nd 

0.317 0.250 0.049 na 0.058 0.295 0.236 0.046 na 0.055 0.022 0.015 0.003 na 0.003 

0.303 0.215 0.048 0.055 0.052 

0.410 0.280 0.061 0.061 0.064 

0.254 0.217 0.043 0.047 0.045 

0.300 0.240 nq 0.053 nq 

0.274 0.281 <0.03 <0.03 <0.03

0.038 0.088 0.264 0.193 0.200 0.279 0.221 0.039 0.052 0.044 0.258 0.208 0.037 0.049 0.041 0.021 0.011 0.005 0.005 0.005 

0.274 0.225 0.039 0.039 0.037 

0.309 0.248 0.050 0.066 0.056 

0.269 0.230 0.059 0.080 0.069

0.699 0.233 0.027 0.044 0.034

0.304 0.234 0.046 0.062 0.055

0.302 0.242 0.044 0.061 0.050 0.266 0.213 0.038 0.053 0.044 0.036 0.029 0.006 0.008 0.006 

1.278 0.923 0.499 0.258 0.268

2 2 2 2 2 22 22 20 20 20 5 5 5 4 5 4 4 4 3 4 

0.038 0.083 0.065 0.083 0.049 0.254 0.193 0.027 0.039 0.034 0.258 0.193 0.037 0.049 0.041 0.017 0.011 0.002 0.001 0.003 

0.041 0.085 0.165 0.138 0.124 0.304 0.237 0.045 0.061 0.050 0.295 0.213 0.040 0.053 0.047 0.022 0.013 0.004 0.005 0.004 

0.044 0.088 0.264 0.193 0.200 1.278 0.923 0.499 0.258 0.268 0.416 0.236 0.105 0.126 0.118 0.036 0.029 0.006 0.008 0.006 

0.032 0.019 0.009 0.010 0.010 0.043 0.027 0.004 0.003 0.009 0.004 0.003 0.002 0.002 

11 8 20 17 21 15 13 11 6 19 18 23 55 45 

6 6 7 4 4 27 21 17 18 20 7 7 5 5 6 5 5 0 0 8 

0.048 0.073 0.063 0.069 0.088 0.328 0.241 0.049 0.063 0.054 0.302 0.218 0.042 0.056 0.051 0.021 0.013 0.005 

0.009 0.024 0.043 0.052 0.042 0.047 0.030 0.010 0.013 0.009 0.031 0.024 0.003 0.007 0.004 0.004 0.004 0.005 

0.303 0.234 0.046 0.061 0.050 0.295 0.213 0.040 0.054 0.047 0.022 0.013 0.004 0.005 0.005 

0.044 0.035 0.010 0.012 0.011 0.043 0.027 0.008 0.009 0.009 

Total β-Carotene, μg/mL trans-β-Carotene, μg/mL Total cis-β-Carotene, μg/mL δ-Tocopherol, μg/mL

C3
Round Robin LXXVI Laboratory Results

All Lab Report 

Lab

FSV-BB

FSV-BC

FSV-BD

FSV-BE

FSV-BFa

FSV-BG

FSV-BH

FSV-BJ

FSV-BK

FSV-BL

FSV-BM

FSV-BN

FSV-BO

FSV-BR

FSV-BS

FSV-BT

FSV-BU

FSV-BV

FSV-BW

FSV-CD

FSV-CE

FSV-CG

FSV-CI

FSV-CO

FSV-CZ

FSV-DD

FSV-DV

FSV-EE

FSV-FK

FSV-FZ

FSV-GD

FSV-GE

N

Min

Median

Max

eSD

eCV

Npast

Medianpast

SDpast

NAV

NAU

407 408 409 410 411 407 408 409 410 411 407 408 409 410 411 407 408 409 410 411 

0.156 0.54 0.152 0.292 0.214 0.088 0.263 0.073 0.133 0.105 0.053 0.051 0.164 0.022 0.098 0.022 0.020 0.020 0.012 0.016 

0.196 0.58 0.185 0.333 0.248 0.117 0.337 0.097 0.174 0.130 0.057 0.054 0.179 0.026 0.106

0.198 0.71 0.164 0.290 0.216 0.060 0.060 0.182 0.023 0.104 

0.170 0.59 0.148 0.342 0.227 0.049 0.055 0.194 0.023 0.120 

0.206 0.81 0.202 0.431 0.292 0.054 0.053 0.183 0.017 0.107

0.136 0.43 0.133 0.245 0.197 0.059 0.048 0.170 0.016 0.098 

0.210 0.57 0.212 0.342 0.280 0.168 0.408 0.165 0.251 0.209 0.095 0.108 0.186 0.076 0.143 

0.102 0.35 0.111 na 0.152 0.092 0.312 0.096 na 0.135 0.039 0.046 0.096 na 0.064 0.012 0.018 0.010 na 0.011 

0.184 0.58 0.189 0.368 0.271 0.056 0.053 0.179 0.019 0.109

0.232 0.68 0.235 0.345 0.297 0.040 0.033 0.167 0.009 0.080

0.168 0.61 0.161 0.281 0.247

0.210 0.75 0.230 0.390 0.330 0.050 nq 0.160 nq 0.100 nq nq nq nq nq

0.171 0.55 0.166 0.294 0.218 0.091 0.279 0.077 0.139 0.102 0.058 0.063 0.155 0.034 0.097

0.184 0.59 0.182 0.312 0.240 0.050 0.049 0.144 0.021 0.088

0.158 0.56 0.156 0.291 0.227

15 15 15 14 15 5 5 5 4 5 13 12 13 11 13 2 2 2 1 2 

0.102 0.35 0.111 0.245 0.152 0.088 0.263 0.073 0.133 0.102 0.039 0.033 0.096 0.009 0.064 0.012 0.018 0.010 0.011 

0.184 0.58 0.166 0.323 0.240 0.092 0.312 0.096 0.157 0.130 0.054 0.053 0.170 0.022 0.100 0.017 0.019 0.015 0.012 0.013 

0.232 0.81 0.235 0.431 0.330 0.168 0.408 0.165 0.251 0.209 0.095 0.108 0.194 0.076 0.143 0.022 0.020 0.020 0.016 

0.033 0.06 0.028 0.046 0.038 0.006 0.049 0.028 0.031 0.038 0.006 0.007 0.018 0.006 0.010 

18 10 17 14 16 6 16 29 20 29 11 12 10 25 10 

20 15 12 13 15 8 7 6 6 7 18 15 12 13 15 4 5 6 4 4 

0.186 0.60 0.174 0.327 0.238 0.100 0.292 0.081 0.148 0.120 0.058 0.053 0.168 0.027 0.100 0.026 0.026 0.025 0.013 0.019 

0.033 0.09 0.030 0.060 0.048 0.017 0.048 0.015 0.033 0.023 0.010 0.016 0.037 0.014 0.027 0.006 0.011 0.013 0.004 0.007 

0.184 0.58 0.166 0.312 0.240 0.092 0.312 0.096 0.174 0.125 0.056 0.053 0.170 0.023 0.100 

0.046 0.12 0.042 0.070 0.057 0.016 0.057 0.028 0.052 0.030 0.013 0.013 0.036 0.006 0.022 

Total β-Cryptoxanthin, μg/mL Total α-Cryptoxanthin, μg/mL Total Lycopene, μg/mL trans-Lycopene, μg/mL

C4
Round Robin LXXVI Laboratory Results

All Lab Report 

Lab

FSV-BB

FSV-BC

FSV-BD

FSV-BE

FSV-BFa

FSV-BG

FSV-BH

FSV-BJ

FSV-BK

FSV-BL

FSV-BM

FSV-BN

FSV-BO

FSV-BR

FSV-BS

FSV-BT

FSV-BU

FSV-BV

FSV-BW

FSV-CD

FSV-CE

FSV-CG

FSV-CI

FSV-CO

FSV-CZ

FSV-DD

FSV-DV

FSV-EE

FSV-FK

FSV-FZ

FSV-GD

FSV-GE

N

Min

Median

Max

eSD

eCV

Npast

Medianpast

SDpast

NAV

NAU

407 408 409 410 411 407 408 409 410 411 407 408 409 410 411 407 408 409 410 411 

0.026 0.046 0.049 0.031 0.039 0.108 0.128 0.122 0.119 0.119

0.76 0.910 1.07 0.910 0.99 0.140 0.312 0.110 0.189 0.13

0.100 0.137 0.118 0.112 0.116

0.028 0.035 0.043 0.020 0.084 0.094 0.114 0.101 0.088 0.153 

0.47 0.863 0.69 0.919 0.88

0.104 0.133 0.140 0.103 0.122 

0.008 0.015 0.012 0.020 0.018 0.088 0.121 0.116 0.109 0.111 0.63 0.908 0.92 0.874 0.91

0.072 0.075 0.088 0.067 0.079 0.204 0.211 0.218 0.204 0.213

0.021 0.028 0.038 na 0.034 0.097 0.114 0.114 na 0.129 0.57 0.778 0.97 na 1.12

0.085 0.119 0.122 0.101 0.116

0.115 0.111 0.126 0.091 0.111

0.96 1.020 1.47 1.090 1.08

0.120 0.140 0.130 0.090 0.130

0.083 0.114 0.113 0.094 0.104

0.015 0.020 0.033 0.011 0.022 0.083 0.101 0.110 0.078 0.094 0.82 1.060 1.21 1.130 1.21 0.109 0.221 0.066 0.129 0.09

0.094 0.120 0.125 0.101 0.119

0.79 0.999 0.98 0.927 1.01

0.74 0.921 1.08 0.931 0.97

0.110 0.290 0.100 0.130 0.12

0.68 0.952 1.10 0.847 0.98

6 6 6 5 6 13 13 13 12 13 9 9 9 8 9 3 3 3 3 

0.008 0.015 0.012 0.011 0.018 0.083 0.101 0.101 0.078 0.094 0.47 0.778 0.69 0.847 0.88 0.109 0.221 0.066 0.129 0.09

0.024 0.032 0.041 0.020 0.037 0.097 0.120 0.122 0.101 0.119 0.74 0.921 1.07 0.923 0.99 0.110 0.290 0.100 0.130 0.12

0.072 0.075 0.088 0.067 0.084 0.204 0.211 0.218 0.204 0.213 0.96 1.060 1.47 1.130 1.21 0.140 0.312 0.110 0.189 0.13

0.010 0.019 0.012 0.013 0.025 0.017 0.012 0.012 0.015 0.012 0.11 0.086 0.15 0.046 0.12

41 60 28 67 67 18 10 10 15 10 15 9 14 5 12

13 8 7 0 9 17 16 12 14 15 5 8 9 9 8 0 0 0 0 

0.022 0.028 0.044 0.034 0.106 0.127 0.124 0.107 0.119 0.72 0.966 1.07 0.955 1.01 

0.005 0.012 0.026 0.014 0.018 0.032 0.031 0.044 0.035 0.10 0.122 0.12 0.052 0.07 

0.024 0.032 0.041 0.025 0.038 0.097 0.120 0.122 0.101 0.119 0.74 0.921 1.07 0.919 0.98 0.110 0.290 0.100 0.130 0.12

0.010 0.019 0.012 0.008 0.026 0.020 0.025 0.025 0.021 0.025 0.11 0.092 0.15 0.092 0.11

Phylloquinone (K1), ng/mL Total Zeaxanthin, μg/mL Total Lutein&Zeaxanthin, μg/mL Coenzyme Q10, μg/mL

C5
Round Robin LXXVI Laboratory Results

All Lab Report Page 5 / 6

Analytes Reported By One Laboratory

Values in μg/mL

Analyte Code 407 408 409 410 411

Phytofluene FSV-BS 0.091 0.327 0.113 0.197 0.162

Total ζ-Carotene FSV-BS 0.082 0.157 0.095 0.120 0.110

Term 

N

Min

Median

Max

SD

CV

Npast

Medianpast

SDpast

NAV

NAU

na 

nd

nq

≥x

italics

 Detected but not quantitatively determined

 Concentration greater than or equal to x

 Not explicitly reported but calculated by NIST from reported values

 = Median for analytes reported by ≥ 5 labs

 NIST Assigned Uncertainty

 = the maximum of (0.05*NAV, SD, SDpast, eSD). 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)

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

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

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

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

 Pooled SD from past RR(s)

 NIST Assigned Value

Table 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

C6
Round Robin LXXVI Laboratory Results

All Lab Report Page 6 / 6

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

FSV-BB 1 1 1 1 1 1 1 1 1 1 1 Lab Participant code

FSV-BC 1 TR Total Retinol

FSV-BD 2 1 aT α-Tocopherol

FSV-BE 3 2 2 1 g/bT γ/β-Tocopherol

FSV-BFa 1 2 bC Total β-Carotene

FSV-BG 1 1 1 1 1 1 1 1 tbC trans-β-Carotene

FSV-BH 3 1 2 2 1 1 1 1 1 1 aC Total α-Carotene

FSV-BJ 1 1 1 1 1 1 1 1 TLy Total Lycopene

FSV-BK 1 1 TbX Total β-Cryptoxanthin

FSV-BL 1 1 TLu Total Lutein

FSV-BM 1 2 TZ Total Zeaxanthin

FSV-BN 1 1 1 3 2 1 1 L&Z Total Lutein & Zeaxanthin

FSV-BO 1 1 1 1 2 1 1 2 1

FSV-BR 2 2 n number of participants providing quantitative data

FSV-BS 1 4 4 4 1 4 3 4 4 % 1 Percent of CS = 1 (within 1 SD of medians)

FSV-BT 3 1 1 1 1 1 2 2 1 1 1 % 2 Percent of CS = 2 (within 2 SD of medians)

FSV-BU 2 2 1 1 1 1 1 1 % 3 Percent of CS = 3 (within 3 SD of medians)

FSV-BV 2 3 3 2 1 2 2 1 % 4 Percent of CS = 4 (3 or more SD from medians)

FSV-BW 4 1 1 1 2 1

FSV-CD 1 1 1 1 2 1 1

FSV-CE 1 2 2

FSV-CG 2 3 2 1 1 1 1 1 1

FSV-CI 2 2 1 2 1 1 1 1

FSV-CO 1 1 1 1 1 1 1

FSV-CZ 3 2 1 2

FSV-DD 1

FSV-DV 1 2

FSV-FK 1 2 4

FSV-FZ 1 1 1 1

FSV-GD 1 1 1 1 1 1 1

FSV-GE 4 4 4

n 30 28 16 22 5 15 15 13 7 6 13

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

% 1 60 54 75 68 80 80 67 69 86 67 92

% 2 20 36 19 18 0 7 33 23 0 17 0

% 3 13 7 6 0 0 7 0 0 14 0 0

% 4 7 4 0 14 20 7 0 8 0 17 8

Comparability Summary

“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 = 



 



 



 



 ++ 22 MINIMUM 4,INTEGER C1 AP

C = Concordance = 

you

N

1i i

i i

N

NAU

You Median you

∑=

−

AP = Apparent Precision = 1N

NAU

You Median

you

N

1i

2

i

i i

you

−















 − ∑=

NAU = NIST Assigned Uncertainty

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 long-term measurement 

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

C7
Appendix D. Representative Individualized Report for RR76 

Each participant in RR76 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:

• Total Retinol

• Retinyl Palmitate

• α-Tocopherol

• γ/β-Tocopherol

• Total β-Carotene

• Total α-Carotene

• Total Lycopene

• trans-Lycopene

• Total β-Cryptoxanthin

• Total Lutein

• Total Zeaxanthin

• Total Lutein & Zeaxanthin

• Coenzyme Q10

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

by participant FSV-BB. 

D1 
 Set 6 of 32

Individualized Report 

Individualized Round Robin LXXVI Report: FSV-B

Summary

Serum 407 Serum 408 Serum 409 Serum 410 

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

Total Retinol 0.342 0.348 29 0.477 0.497 29 0.444 0.452 29 0.452 0.451 28 

Retinyl Palmitate 0.10 0.09 5 0.1 0.0 5 0.0 0.0 5 0.03 0.02 5 

α-Tocopherol 4.62 4.31 28 10.63 10.35 28 7.26 6.93 28 8.20 8.00 27 

γ/β-Tocopherol 1.629 1.637 16 1.408 1.409 16 1.726 1.721 16 1.835 1.854 15 

δ-Tocopherol 0.044 2 0.083 2 0.065 2 0.083 2 

Total β-Carotene 0.320 0.303 22 0.242 0.234 22 0.042 0.046 20 0.055 0.061 20 

trans-β-Carotene 0.304 0.295 5 0.231 0.213 5 0.040 0.040 5 0.054 0.054 4 

Total cis-β-Carotene 0.017 0.022 4 0.011 0.013 4 0.002 0.004 4 0.001 0.005 3 

Total α-Carotene 0.021 0.016 14 0.032 0.032 15 0.014 0.015 14 0.042 0.041 14 

Total Lycopene 0.156 0.184 15 0.543 0.585 15 0.152 0.166 15 0.292 0.312 14 

trans-Lycopene 0.088 0.092 5 0.263 0.312 5 0.073 0.096 5 0.133 0.174 4 

Total β-Cryptoxanthin 0.053 0.056 13 0.051 0.053 12 0.164 0.170 13 0.022 0.023 11 

Total α-Cryptoxanthin 0.022 2 0.020 2 0.020 2 0.012 1 

Total Lutein 0.082 0.076 7 0.083 0.086 7 0.073 0.077 7 0.087 0.089 6 

Total Zeaxanthin 0.026 0.024 6 0.046 0.032 6 0.049 0.041 6 0.031 0.025 5 

Total Lutein&Zeaxanthin 0.108 0.097 13 0.128 0.120 13 0.122 0.122 13 0.119 0.101 12 

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 Email: 

D2
 Set 6 of 32

Individualized Report Page 2 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total Retinol, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D3
 Set 6 of 32

Individualized Report Page 3 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Retinyl Palmitate, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D4
 Set 6 of 32

Individualized Report Page 4 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

α-Tocopherol, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D5
 Set 6 of 32

Individualized Report Page 5 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

γ/β-Tocopherol, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D6
 Set 6 of 32

Individualized Report Page 6 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total β-Carotene, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D7
 Set 6 of 32

Individualized Report Page 7 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total α-Carotene, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D8
 Set 6 of 32

Individualized Report Page 8 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total Lycopene, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D9
 Set 6 of 32

Individualized Report Page 9 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

trans-Lycopene, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D10
 Set 6 of 32

Individualized Report Page 10 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total β-Cryptoxanthin, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D11
 Set 6 of 32

Individualized Report Page 11 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total Lutein, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D12
 Set 6 of 32

Individualized Report Page 12 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total Zeaxanthin, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D13
 Set 6 of 32

Individualized Report Page 13 / 14

Individualized RR LXXVI Report: FSV-BB

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 Comments History

#407 Lyophilized, native, single-source 28#184, 59#319, 60#327

#408 Fresh-frozen, native, multi-donor: SRM 968e II 66#358, 67#364, 69#374, 71#386, 74#399

#409 Fresh-frozen, native, single-donor 71#386, 72#390

#410 Fresh-frozen, native, single-donor 71#384

#411 Mixture of (310 mL #409) and (260 mL #410) 71#385, 73#396

Total Lutein&Zeaxanthin, μg/mL

184319327407358364374386399408383390409385396411384410

[Analyte], μg/mL Apparent Precision, SD

Concordance, SD

Your [Analyte], μg/mL

Median [Analyte], μg/mL

Long-term Precision, SD

Apparent Precision, SD

You, this RR

You, past RRs Others, this RR

1st Quartile (25%)

Median (50%)

3rd Quartile (75%)

Expectation

You, ≥x, this RR

You, ≥x, past RRs

D14
 Set 6 of 33

10/3/2014 

Total Retinol α-Tocopherol Total β-Carotene To

Retinyl palmitate γ/β-Tocopherol Total Lutein tra

Total α-Carotene Total β-Cryptoxanthin Total Lutein&Zeaxanthin Co

Individualized Round Robin LXXVI Report: FSV-BB 

Graphical Comparability Summary

D15
Appendix E. Shipping Package Inserts for RR41 

The following three items were included in each package shipped to an RR41 participant:

• Cover letter

• Analysis of Control Materials and Test Samples 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. This bag was labeled:

The packing list was placed at the top of the shipping box, between the cardboard 

covering and the foam insulation.

NIST MMQAP-VC: RR 41

Micronutrients Measurement Vitamin C

Quality Assurance Program

Summer 2014 Controls & 

Samples 

Analyze after: June 1, 2014

Results due on or before:

September 15, 2014

E1 

Participant #: Date: 

Vitamin C Round Robin 41 

NIST Micronutrient Measurement Quality Assurance Program

Analysis of Control Materials and Test Samples

Sample Replicate 1 Replicate 2 Units

Control serum CS#3 μmol/L of Sample

Target: (15.5 ±1.6) μmol/L

Control serum CS#4 μmol/L of Sample Target: (46.1 ±4.6) μmol/L

Test sample #411 μmol/L of Sample

Test sample #412 μmol/L of Sample

Test sample #413 μmol/L of Sample

Test sample #414 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:

Nature of samples you typically analyze: native | MPA-preserved | DTT-preserved | Other

If “Other”, please describe:

COMMENTS:

Please return by September 15, 2014

MMQAP Fax: 301-977-0685 

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

Gaithersburg, MD 20899-8392 

E3
Participant #: ________ Date: _____________

Mail: M2QAP

 NIST, Stop 6392

 Gaithersburg, MD 20899-6392

Fax: 301-977-0685

Email: David.Duewer@NIST.gov

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

Label Form

VitC #411 Liquid frozen (1:1 serum:10% MPA) SRM970 Lv1

VitC #412 Liquid frozen (1:1 serum:10% MPA) Sam - 30's

VitC #413 Liquid frozen (1:1 serum:10% MPA) SRM970 Lv2

VitC #414 Liquid frozen (1:1 serum:10% MPA) Sam - 50's

CS#3 Liquid frozen (1:1 serum:10% MPA) Red

CS#4 Liquid frozen (1:1 serum:10% MPA) Orange

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) Email (david.duewer@nist.gov) or fax (301-977-0685) us the

following information:

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

Your prompt return of this information is appreciated.

The M2QAP Gang

Packing List and Shipment Receipt Confirmation Form

NIST Micronutrients Measurement Quality Assurance Program

Vitamin C Round Robin 41

E4
Appendix F. Final Report for RR410 

The following three pages are the final report for RR41 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 
October 3, 2014 

Dear Colleague:

Enclosed is the summary report of the results for Round Robin 41 (RR41) for the measurement of total 

ascorbic acid (TAA, 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 “adjusted 

median absolute deviation from the median” (MADe) is used to estimate the expected standard deviation, 

and we estimate the coefficient of variation (CV) as 100×MADe/median.

RR41 consisted of one vial each of four test samples (#411, #412 #413, and #414) and one vial each of 

two control samples (CS#3 and CS#4). Both the test and control samples are 1:1 mixtures of serum and 

10 % metaphosphoric acid augmented with high-purity ascorbic acid. Details regarding the samples can 

be found in the enclosed report. 

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

unit of Standard Reference Material (SRM) 970 Vitamin C in Frozen Human Serum. SRM 970 can be 

purchased from the NIST SRM Program at www.nist.gov/srm; phone: 301-975-6776; fax: 301-948-3730. 

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

consultation. 

If you returned your intent-to-participate form for the 2015 NIST Micronutrients Measurement Quality 

Assurance Program (MMQAP), you should have received a confirmation receipt. Please notify us if you 

have not received your confirmation receipt. 

Laboratories participating in the upcoming program will receive samples for the two vitamin C in serum 

studies (RR42 and RR43) in February 2015. Please note that we will ship the samples for both studies at 

the same time in February. Results will be due in May 2015 for the first study and in September 2015 for 

the second study. We will send you a reminder in late July 2015 about the reporting deadline for the 

second study. Please contact us immediately if this schedule is problematic for your laboratory. 

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

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

Sincerely,

Jeanice Brown Thomas, M.B.A. David L. Duewer, Ph.D. 

Research Chemist Research Chemometrician

Chemical Sciences Division Chemical Sciences Division

Material Measurement Laboratory Material Measurement Laboratory

Enclosures 

UNITED STATES DEPARTMENT OF COMMERCE

National Institute of Standards and Technology

Gaithersburg, Maryland 20899-8410

F2
The NIST MMQAP Vitamin C Round Robin 41 (RR41) report consists of: 

Page “Individualized” Report

1 Summary of your reported values for the two serum control and four serum test samples. 

2 Graphical summary of your RR41 measurements.

Page “All-Lab” Report

1 A tabulation of results and summary statistics for total ascorbic acid [TAA] in the RR41 

control and test samples. Results and summary statistics are also presented for the test 

samples calibrated to the results for the control samples using both 2-point proportional and 

linear models.

Serum-Based Samples. Two serum controls and four test samples were distributed in RR41. 

CS#3 Material ampouled in 2009 containing 15.4 ±0.4 μmol/L [TAA] 

CS#4 Material ampouled in 2009 containing 46.2 ±1.2 μmol/L [TAA] 

S41:1 Ampouled in late 2009, previously distributed in RRs 34, 36 (as two samples), 38 and 40 

S41:2 Ampouled in late 2009, previously distributed in RRs 32, 35, 36 and 38 

S41:3 Ampouled in late 2009, previously distributed in RRs 32, 33, 35, 38 and 40 

S41:4 SRM 970 level 1, ampouled in mid-1998, previously distributed as a test sample in RRs 

11 to 16, 19, 20 23, 25, 29, 31, 34, 37 and 39 

Results. 

1) The reported [TAA] contents of the two control sera (CS#3 and CS#4) are unchanged from the values

estimated for these materials when they were distributed as unknowns. The expected [TAA] content 

and inter-participant standard deviations are estimated with the robust median and adjusted median 

absolute deviation (eSD) statistics.

2) There is no evidence for any significant change in the [TAA] level for any of the four test materials.

3) The results for two control sera with well separated [TAA] levels enable calibration of the reported

results for the unknowns to the both proportional and linear models. The proportional model is:

[TAA]reportedCS = b × [TAA]referenceCS

where [TAA]reportedCS are the reported values for the two control sera, [TAA]referenceCS are the 

established reference values for these materials, and b is estimated using least-squares regression. 

The inverse model for estimating calibrated values for unknown samples is then:

[TAA]calibrated = [TAA]reported / b. 

The linear model and its inverse are: 

[TAA]reportedCS = a + b × [TAA]referenceCS; [TAA]calibrated = ([TAA]reported – a) / b .

where the a and b parameters are defined by the line between the {reference, reported} values for the 

two control sera.

Summary Report F3 1 / 2
Figure 1 displays eSD as a function of the Median values for the test samples distributed in RR34 

through RR41 where the CS#3 and CS#4 were distributed as either test or control samples. 

Figure 1: Estimated Standard Deviation as a Function of Median Value 

Each symbol represents the summary statistics for one of the test samples distributed in RR34 through RR41. The 

solid red circles represent the results as they were reported (i.e., uncalibrated); the red line represents a “best fit” 

functional relationship between the eSD and the median. The open blue squares and blue line represent the reported 

test-sample results after calibration to the control samples using the proportional model. The open green diamonds 

and green line represent the results after calibration to the linear model.

The relationship between the eSD and the median values for the “As Reported” results is adequately 

described as a constant coefficient of variation, eCV = 100*eSD/Median, of 7.1 %. The best-fit 

relationship for the results calibrated to the proportional model is more complex, with a fairly constant 

component of 0.80 μmol/L for [TAA] levels of 20 μmol/L or less and a constatnt eCV of 3.0 % above 

20 μmol/L. The best-fit relationship with the linear model calibration is a constant eSD of 1.0 μmol/L 

regardless of [TAA].

Since calibration using the proportional model tends to increase the variability for the lower [TAA] 

samples but does not completely stabilize it at higher levels, the proportional calibration model appears to 

be inferior to the linear model. While calibration to the two control samples dramatically reduces 

interlaboratory variability for the higher [TAA] materials, it increases variability at the lower [TAA] 

levels.

The addition of the RR41 results to those from the previous studies do not significantly impact the above 

analysis. Consequently, we will not distribute control materials in the 2015 vitamin C studies. 

0

1

2

3

4

5

6

0 20 40 60

Estimated SD (eSD), 

μmol/L

Median, μmol/L

As Reported

eSD = 0.071 × Median

[TAA]' = [TAA]/b

[TAA]' = ([TAA]-a)/b

eSD' = 1.005

Summary Report F4 2 / 2
Appendix G. “All-Lab Report” for RR41 

The following two pages are the “All-Lab Report” for RR41 as provided to all 

participants, with the following exceptions:

• the participant identifiers (Lab) have been altered.

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

• the Legend page has been added

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 Ascorb

"Round Robin" 41 - Fall 2014

All Lab Report 

Param

Lab Date CS#3 CS#4 S41:1 S41:2 S41:3 S41:4 b S41:1' S41:2' S41:3' S41:4' b a S

VC-MB 14/08/14 14.2 45.9 57.6 30.7 22.7 8.5 0.99 57.9 30.9 22.8 8.6 1.03 -1.5 

VC-MC 12/09/14 15.1 44.8 55.6 29.7 23.1 7.5 0.98 56.9 30.4 23.6 7.7 0.97 0.5 

VC-MG 22/08/14 15.4 48.8 60.8 29.8 23.5 8.2 1.06 57.5 28.2 22.2 7.8 1.09 -1.2 

VC-MH 14/08/14 15.7 44.1 53.3 29.4 22.4 8.2 0.97 55.1 30.4 23.1 8.4 0.93 1.5 

VC-MI 15/09/14 14.8 45.9 57.5 31.4 23.7 9.3 1.00 57.7 31.5 23.7 9.3 1.01 -0.6 

VC-MJ 09/09/14 18.8 49.0 66.3 38.0 30.4 9.1 1.08 61.1 35.0 28.0 8.4 0.98 3.9 

VC-MN 05/08/14 15.1 42.2 52.5 28.6 19.3 7.1 0.93 56.8 30.9 20.8 7.6 0.88 1.6 

VC-NM 12/09/14 13.6 43.5 54.9 28.9 21.6 8.7 0.94 58.3 30.7 22.9 9.2 0.97 -1.3 

VC-NX 15/09/14 13.9 49.2 59.9 32.7 23.1 7.0 1.06 56.8 30.9 21.9 6.6 1.15 -3.6 

9 9 9 9 9 9 9 9 9 9 

15.2 45.9 57.6 31.0 23.3 8.2 57.5 31.0 23.2 8.2 

1.5 2.6 4.3 2.9 3.0 0.8 1.6 1.8 2.0 0.8 

13.6 42.2 52.5 28.6 19.3 7.0 55.1 28.2 20.8 6.6 

14.2 44.1 54.9 29.4 22.4 7.5 56.8 30.4 22.2 7.7 

15.1 45.9 57.5 29.8 23.1 8.2 57.5 30.9 22.9 8.4 

15.4 48.8 59.9 31.4 23.5 8.7 57.9 30.9 23.6 8.6 

18.8 49.2 66.3 38.0 30.4 9.3 61.1 35.0 28.0 9.3 

0.9 3.7 4.0 1.4 0.8 1.1 1.1 0.7 1.1 1.0 

6 8 7 5 4 13 2 2 5 12 

%25

Samples Calibrated Results: [TAA]' = TAA/b Calibrated R

Total Ascorbic Acid ([TAA]), μmol/L [TAA]', μmol/L Parameters 

Median

%75

Max

eSD

eCV

N

Average

SD

Min

G2
Micronutrients Measurement Quality Assurance Program for Total Ascor

"Round Robin" 41 - Summer 2014

All Lab Report 

Term Definition

Lab Participant code

Date Date results received at NIST

b Slope and Intercept of the line connecting the expected values

a for control samples CS#3 and CS#4 with the results reported

 by each participant

N Number of quantitative values reported for this analyte

Average Mean of the reported quantitative values

SD Standard deviation of the reported quantitative values

Min Minimum quantitative value reported

%25 First quartile of the reported quantitative values

Median Median (second quartile) of the reported quantitative values

%75 Third quartile of the reported quantitative values

Max Maximum quantitative value reported

eSD Robust standard deviation, estimated using the adjusted

 median absolute deviation from the median (MADe)

eCV Robust Coefficient of Variation, estimated as 100*eSD/Median

Legend

G3
Appendix H. Representative “Individualized Report” for RR41 

Each participant in RR41 received an “Individualized Report” reflecting their reported 

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

“VC-MB”.

H1
 Set 2 of 10

Individualized Report Page 1/2

Date RR Sample Rep1 Rep2 Fadj Mean SDdup N Mean SDrepeat SDreprod

01/14/11 34 S34:4 56.8 57.3 1.0 57.0 0.4 6 57.5 0.6 1.3

03/07/12 36 S36:1 57.8 56.8 1.0 57.3 0.7

03/07/12 36 S36:4 56.8 55.2 1.0 56.0 1.1

02/27/13 38 S38:4 57.3 56.8 1.0 57.0 0.4

02/24/14 40 S40:4 59.9 59.9 1.0 59.9 0.0

08/14/14 41 S41:1 57.3 57.8 1.0 57.6 0.4

01/13/10 32 S32:3 30.5 31.0 1.0 30.7 0.4 5 30.9 0.5 0.6

06/13/11 35 S35:3 32.0 31.5 1.0 31.7 0.4

03/07/12 36 S36:2 31.5 30.5 1.0 31.0 0.7

02/27/13 38 S38:3 29.9 30.5 1.0 30.2 0.4

08/14/14 41 S41:2 30.5 31.0 1.0 30.7 0.4

01/13/10 32 S32:2 22.2 22.7 1.0 22.5 0.4 6 22.8 0.6 0.7

07/23/10 33 S33:4 23.2 22.7 1.0 23.0 0.4

06/13/11 35 S35:2 23.7 23.7 1.0 23.7 0.0

02/27/13 38 S38:2 21.2 22.2 1.0 21.7 0.7

02/24/14 40 S40:3 23.7 22.7 1.0 23.2 0.7

08/14/14 41 S41:3 22.2 23.2 1.0 22.7 0.7

09/25/98 11 S11:1 25.0 25.0 0.5 12.5 0.0 16 9.4 0.6 1.6

02/26/99 12 S12:1 18.0 18.0 0.5 9.0 0.0

03/03/00 13 S13:1 24.0 24.0 0.5 12.0 0.0

03/26/01 14 S14:3 19.6 19.6 0.5 9.8 0.0

09/05/01 15 S15:1 25.8 23.7 0.5 12.4 0.7

02/08/02 16 S16:1 18.7 18.7 0.5 9.4 0.0

05/01/03 19 S19:4 19.6 19.6 0.5 9.8 0.0

03/01/04 20 S20:3 7.8 10.9 1.0 9.3 2.2

05/25/05 23 S23:4 7.7 7.7 1.0 7.7 0.0

05/24/06 25 S25:1 8.8 8.8 1.0 8.8 0.0

06/20/08 29 S29:2 8.3 7.7 1.0 8.0 0.4

08/05/09 31 S31:3 8.8 8.3 1.0 8.5 0.4

01/14/11 34 S34:1 7.7 7.7 1.0 7.7 0.0

08/06/12 37 S37:1 8.8 na 1.0 8.8

08/01/13 39 S39:1 8.3 7.7 1.0 8.0 0.4

08/14/14 41 S41:4 8.8 8.3 1.0 8.5 0.4

National Institute of Standards and Technology Email: david.duewer@nist.gov

Vitamin C "Round Robin" 41 Report: Participant VC-MB

[TAA] mmol/Lsample

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

Micronutrients Measurement Quality Assurance Program Fax: (301) 977-0685

H2
 Set 2 of 10

9/30/2014 Page 2 / 2

Vitamin C "Round Robin" 41 Report: Participant VC-MB 

Total Ascorbic Acid, μmol/mL

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

S41:1 Prepared 2009; distributed RRs 34,36(dups),38,40

S41:2 Prepared 2009; distributed RRs 32,33,35,38

S41:3 Prepared 2009; distributed RRs 32,33,35,38,40

S41:4

Comments

SRM970 Lv I; prepared 1998; distributed as unknowns RRs 11 - 16,19,20,23,25,29,31,34,37,39

RR34RR36RR36RR38RR40RR41RR32RR35

RR36RR38RR41RR32RR33RR35RR38RR40RR41RR11RR12RR13RR14RR15RR16RR19RR20RR23RR25RR29RR31RR34RR37RR39RR41

[Total Ascorbic Acid], μmol/L

Your [Total Ascorbic Acid], μmol/L

Median [Total Ascorbic Acid], μmol/L

You, this RR

You, past RRs

NIST, RR 22

Others, this RR 1st Quartile (25%)

Median (50%)

3rd Quartile (75%) Apparent Precision, SD

Concordance, SD

H3