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Vitamin A Laboratory External Quality Assurance Program

Start Date: 2003


The Vitamin A Laboratory External Quality Assurance (VITAL-EQA) Program was established as part of a global effort to strengthen the capacity and analytical accuracy of nutrition laboratories. The CDC Global Micronutrient Laboratory currently administers the VITAL-EQA Program.

The VITAL-EQA Program is a standardization program designed to provide laboratories that measure nutritional biomarkers with an independent assessment of their analytical performance. Results are not used for accreditation or certification purposes. The program has the following goals:

  • To help laboratories maintain and improve the quality of their nutritional biomarker measurements.
  • To ensure that each major region of the world has a few laboratories that can reliably perform measurements of nutritional biomarkers for nutrition surveys for public health assessments and research studies.

Initially focused exclusively on vitamin A, the program has expanded in response to interest in additional biomarkers.

Twice a year, member laboratories receive (free-of-charge) one or more sets of serum samples that they test for any or all of the following biomarkers:

  • Retinol
  • Vitamin D, 25-hydroxy
  • C-reactive protein (CRP)
  • B-vitamin biomarkers: folate, B12, methylmalonic acid (MMA), homocysteine
  • Iron biomarkers: ferritin, soluble transferrin receptor (sTfR), iron, total iron-binding capacity/unbound iron-binding capacity (TIBC/UIBC)

Laboratories must meet the following eligibility requirements to participate in the VITAL-EQA Program:

  • Laboratories must be able to receive frozen samples, retrieve them from customs in a timely manner, and accept responsibility for any costs associated with customs.
  • Laboratories must complete the sample analysis and provide the results to CDC within a specified period of time (approximately 6 weeks).


As of March 2009, The VITAL-EQA Program has recruited the participation of 38 laboratories from various regions of the world:

RegionNumber of VITAL-EQA laboratories
Africa7 laboratories
The Americas12 laboratories
Eastern Mediterranean6 laboratories
Europe3 laboratories
Southeast Asia9 laboratories
Western Pacific1 laboratory

Program achievements include the following:

  • Publication of summary findings from six rounds of the program conducted between 2003 and 2006 in Clinica Chimica Acta 390 90–96 (2008).
  • Enrollment of between three and seven laboratories each year since inception of the program.

Future Plans

Future plans include the following activities:

  • Add retinol binding protein (RBP) as one of the nutritional biomarkers that the program offers.
  • Expand the program as the budget allows.

For More Information

For more information about the VITAL-EQA Program, please contact or see CDC Vitamin A Laboratory – External Quality Assurance.

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