NIST Releases New SRMs for Monitoring Human Exposure to Environmental Toxins

In collaboration with the CDC, NIST has created two new Standard Reference Materials (SRMs) for measurements of human exposure to environmental toxins. Used to check the accuracy of tests and analytical procedures, SRMs 3668, “Mercury, Perchlorate, and Iodide in Frozen Human Urine” and 2668, “Toxic Elements in Frozen Human Urine” will add measures for emerging environmental contaminants such as perchlorate, a chemical that the EPA now regulates. Non-invasive urine samples, which can reflect exposures as recent as two days, are collected and frozen until testing. To produce comparable results among tests, the physical, chemical and biological properties of a reference material should closely mimic how a specimen would respond to these tests. NIST researchers developed these new SRMs to replace the freeze-dried SRMs 2670a, 2671a and 2672a because when the frozen urine SRM is thawed it matches the properties of clinical urine specimens much more closely than reconstituted freeze-dried urine SRM. The CDC, Mayo Clinic and the New York State Department of Health have made certification measurements of the two SRMs to ensure their relevance for the intended applications as well. The SRMs will be used as quality controls for urine tests during NIST’s biennial National Health and Nutrition Examination Survey.