Approximately 75% of the U.S. population takes dietary supplements, including vitamins and mineral supplements, representing an annual expenditure of more than $20 billion. Regulations driven by reported cases of inaccurate labeling, adulteration, contamination (with pesticides, heavy metals, or toxic botanicals), and drug interactions are now in place that require manufacturers to evaluate the identity, purity, and composition of their ingredients and finished products. In 2007, a Dietary Supplements Laboratory Quality Assurance Program (DSQAP) was initiated to enable participants to improve the accuracy and precision of their measurements for nutrients, marker compounds, toxic elements, and/or pesticides in dietary supplement ingredients and finished products. Approximately two intercomparison exercises were planned each year, with five to seven sample sets distributed in each exercise. Samples prepared and distributed by NIST were commercial samples with values assigned by NIST, or Standard Reference Materials available from NIST.
The intercomparison exercises, data reports, and workshops were designed to provide participating laboratories with the tools to evaluate their dietary supplement analytical methodology. Information gained through participation may be used by the participants to demonstrate "appropriateness" of analytical methodology to regulatory agencies and to improve the quality of information associated with dietary supplement products through increased measurement capabilities.
For participants to access historical results, log in using your existing credentials at HAMQAP.