The measurement of cholesterol in serum: reference method.

Measurement of cholesterol is sufficiently important in the diagnosis of cardiovascular disease so that a reference method should be available in the laboratory for evaluation of the rapid screening procedures in common use. With this in mind, a critical evaluation of the Abell procedure was carried out. The ex­ traction procedure, the effect of interfering substances, the effect of time and tempera­ ture, the effect of light, the saponification pro­ cedure, reproducibility, and the effect of varia­ tions in the preparation of the LiebermannBurchard reagent were critically examined. The accuracy and reproducibility of the method were confirmed, and it was consid­ ered to be a most suitable reference proce­