Immunoassay of apolipoprotein-B of low density lipoproteins in plasma

Method of assaying the apolipoprotein B (apo B) of low density lipoproteins (LDL) in serum enabling the performance successively, in a single operation, of separation of the LDLs from other lipoproteins containing apo-B by electrophoresis in a polyacrylamide gel having a controlled degree of cross-linking and assay of the apo-B of the LDLs thus separated by electro-immunodiffusion in an agarose gel containing anti-apo B. Samples are placed in wells formed in the acrylamide gel, and the height of the precipitation arcs in the agarose gel is measured.