Estimation of low-density lipoprotein immunoprecipitates in uniform drops of serum.

An immunochemical technic has been found to be specific, efficient and reproducible in removing lipoproteins of density less than 1.063 gm./ml. from measured drops of human serum. Estimations of microcapillary columns of immunoprecipitate compare favorably with ultracentrifugal analysis of Sf 0-400 lipoproteins. An equation derived from these data converts millimeters of lipoprotein precipitate into milligrams lipoprotein Sf 0-400 per 100 ml. serum. A highly significant difference was obtained between mean lipoprotein precipitate levels of a clinically healthy population and those of a group of patients with coronary artery disease or diabetes mellitus.