Micronutrients Measurement Quality Assurance Program

Background

For the past 28 years the National Institute of Standards and Technology (NIST) has coordinated the Micronutrients Measurement Quality Assurance (QA) Program for laboratories that measure vitamins and carotenoids in human serum and plasma. Interlaboratory comparison studies are currently directed toward the measurement of retinol, gamma-tocopherol, alpha-tocopherol, beta-carotene, and ascorbic acid. Laboratories also report values for delta-tocopherol, retinyl palmitate, alpha-carotene, lycopene, beta-cryptoxanthin, lutein, zeaxanthin, 25-hydroxyvitamin D, coenzyme Q10, vitamin K1, and other related measurands. Frozen or freeze-dried sera are sent to laboratories biannually (winter and spring) for analysis. Results are then returned to NIST for data evaluation and tabulation. Value-assignment of the sample pools is based on the median of all the laboratory results, with confirmation based on measurement at NIST using two or more different methods. Consultation and troubleshooting regarding methods of analysis are also provided. A micronutrient analysis QA workshop for fat-soluble vitamin and carotenoid analysis and for ascorbic acid in serum analysis is hosted as well. A certificate of participation in the QA program, which displays the laboratory's measurement performance summary for all analytes reported, is issued at the end of each calendar year.

Program Costs (for 2012)

How to Join the Program

If you are interested in joining our program, please download and print the enrollment form (PDF format). You may also obtain more information or enroll by contacting the Micronutrients Measurement Quality Assurance Program at the address shown below.

Micronutrients Measurement Quality Assurance Program
NIST
100 Bureau Dr, Stop 8392
Gaithersburg, MD 20899-8392
Fax:  301-977-0685

Related Standard Reference Materials (SRMs) 968e and 970

We recommend that labs obtain Standard Reference Material (SRM) SRM 968e Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum and SRM 970 Ascorbic Acid in Human Serum at the outset of their participation in the QA program to validate their methodology and to value assign in-house control materials. These SRMs may be purchased from the Standard Reference Materials Program at NIST (301-975-2200; fax: 301-948-3730; or e-mail: srminfo@nist.gov).

Micronutrients Measurement Quality Assurance Workshop

This workshop is intended for laboratories that measure vitamins and carotenoids in human serum and plasma as part of the QA program. This workshop provides a forum for participants to discuss analytical methods, results of the intercomparison exercises, and other related topics. There is no registration fee.

Related Publications

1. Brown Thomas, J. and Sharpless, K. E., eds., Methods for Analysis of Cancer Chemopreventive Agents in Human Serum; National Institute of Standards and Technology: Gaithersburg, MD, (1995).
2. Brown Thomas. J.; Kline, M.C.; Gill, L.M.; Yen, J.H.; Duewer, D.L.; Sniegoski, L.T.; and Sharpless, K.E. Preparation and Value Assignment of Standard Reference Material 968c Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum, Clin. Chim. Acta., 305 (2001), 141-155.
3. Duewer, D.L., Brown Thomas, J., Kline, M.C., MacCrehan, W.A., Schaffer, R., Sharpless, K.E., May, W.E., NIST/NCI Micronutrients Measurement Quality Assurance Program: Measurement Reproducibility, Repeatability, Stability, and Relative Accuracy for Fat-Soluble Vitamin-Related Compunds in Human Sera, Anal. Chem. 69 (1997), 1406-1416.
4. Duewer, D. L.; Kline, M. C.; Sharpless, K. E.; Brown Thomas, J. M.; Gary, K. T.; Sowell, A. L. Micronutrients Measurement Quality Assurance Program: Helping Participants Use Interlaboratory Comparison Exercise Results to Improve their Long-term Measurement Performance. Anal. Chem. 71 (1999) 1870-1878.
5. Duewer, D. L.; Kline, M. C.; Sharpless, K. S.; Brown Thomas, J. NIST Micronutrients Measurement Quality Assurance Program: Characterizing Individual Participant Measurement Performance Over Time, Anal. Chem., 72(15) (2000), 3611-3619.
6. Duewer, D. L.; Kline, M. C.; Sharpless, K. S.; Brown Thomas, J. NIST Micronutrients Measurement Quality Assurance Program: Characterizing the Measurement Community's Performance Over Time. Anal. Chem. 72(17) (2000), 4163-4170
7. Margolis, S. A.; Duewer, D. L. The Measurement of Ascorbic Acid in Human Plasma and Serum: Intralaboratory Repeatability, Interlaboratory Repeatability, Interlaboratory Reproducibility, and Stability in Lyophilized Plasma and Metaphosphoric Acid Preserved Plasma and Serum. Clin. Chem. 42 (1996), 1257-1262.
8. Margolis, S.A., Vangel, M., and Duewer, D.L., Certification of SRM 970, Ascorbic Acid in Serum, and the Analysis of Associated Interlaboratory Bias in the Measurement Process, Clin. Chem., 49 (2003), 463-469.
9. Sharpless, K. E.; Duewer, D. L. Population Distributions and Intralaboratory Variance for Fat-Soluble Vitamin-Related Compounds in Human Serum. Anal. Chem. 67 (1995), 4416-4422.
10. Thomas, J. B.; Duewer, D. L.; Mugenya, I. O.; Phinney, K. W.; Sander, L. C.; Sharpless, K. E.; Sniegoski, L. T.; Tai, S. S.; Welch, M. J.; Yen, J. H. Preparation and Value Assignment of Standard Reference Material 968e Fat-Soluble Vitamins, Carotenoids, and Cholesterol in Human Serum, Anal. Bioanal. Chem. 402 (2012) 749-762.