The National Institute of Standards and Technology (NIST) and the NationalInstitutes of Health (NIH) Office of Dietary Supplements (ODS) have establisheda Vitamin D Metabolites Quality Assurance Program (VitDQAP). Interlaboratorycomparison studies are currently directed toward the measurement of25-hydroxyvitamin D2, 25-hydroxyvitamin D3, and3-epi-25-hydroxyvitamin D3 in selected serum and plasma matrices aswell as method-appropriate control materials. Frozen or freeze-driedserum or plasma samples together with control materials are sent tolaboratories biannually (winter and summer) for analysis. Results are thenreturned to NIST for data evaluation and tabulation. Value-assignment of thesamples is based on the median of all the laboratory results, with confirmationbased on measurement at NIST using one or more different methods. Consultationand troubleshooting regarding methods of analysis are also provided. A reportof exercise results is sent to participants, and workshops will bescheduled periodically to discuss results as well as methodological issues andadvancements in clinically-relevant vitamin D metabolite measurements.
Standard Reference Material (SRM) 972a and SRM 2972
VitDQAP Exercise Workshops
VitDQAP workshops (or webinars) are held for laboratories that measure vitamin D metabolites in human serumand plasma as part of the QA program. These workshopsprovide an opportunity for participants to discuss analyticalmethods, results of the interlaboratory comparison exercises, and other relatedtopics.
Certificates and Reports
Reports for the first six exercises have been published:
An example figure from the Summer 2011 Report illustrating the 25-hydroxyvitamin D (25(OH)DTotal) levels in two study materials as determined by immunoassay (CLIA, EIA and RIA) and LC (LC-MSn and LC-UV) methods is shown below.
Certificates of participation can also be provided upon individual request.
CONFIDENTIALITY STATEMENT: It is our policy that participants' laboratory identification numbers remain confidential and known only to them and ourselves.
How to Join the Program
If you are interested in joining our program, please send an e-mail to email@example.com. There is no fee for participation.