The method of determination must be considered in interpreting blood cholesterol levels.

Based on the results of recent clinical trials, physicians have been encouraged to screen and treat patients for hypercholesterolemia. Since the data from the Lipid Research Clinics (LRC) have been used to define the patient population that should be treated, a comparison of LRC cholesterol results with those obtained with two commonly used clinical laboratory instruments was performed. Both the Technicon SMAC and the Du Pont aca had positive bias compared with the LRC method. Therefore, many patients with cholesterol concentrations greater than 265 mg/dL (6.85 mmol/L) as determined by these routinely used methods have markedly lower levels determined by LRC methods. These findings not only indicate that rigorous interlaboratory standardization is required to conform to LRC reference values, but they also suggest that the clinician should be aware of these methodological considerations when the decision to treat hypercholesterolemia is made.