The National Institutes of Health (NIH), through its National Cholesterol Education Program (NCEP), has established test protocols and guidelines for acceptable deviation from "truth", or the NRS/Chol (the National Reference System for Cholesterol) reference value. These guidelines state that Total System Error (TSE) should be within the following limits from reference when these test protocols are followed:

CRMLN

PTS Total Cholesterol and HDL Cholesterol are CRMLN certified as of 2009. Click here for a copy of the CRMLN certifications.

Reference Value

Because variability and system error are present in all commercial methods for determining lipid concentration, determining the reference value can be difficult. The reference value is typically defined as the result given by the standard methods established by the Center for Disease Control and Prevention (CDC) for lipid analyses.

CRMLN Reference Labs

The CDC established reference laboratories in the US ("Cholesterol Reference Method Laboratory Network" [CRMLN]) to evaluate and certify manufacturers’ lipid products against reference standards. For a link to the CRMLN website, click here.