Simultaneous quantification by double rocket immunoelectrophoresis of apolipoproteins A-I and B in blood spotted on filter paper.

We describe double rocket immunoelectrophoresis for simultaneous quantification of apolipoprotein A-I (apo A-I) and B (apo B) in blood on filter paper. The apolipoproteins from blood spots on filter paper were eluted with detergents (sodium dodecyl sulfate and Triton X-100). The eluates were subjected to electrophoresis on agarose gel containing antisera against both apolipoproteins. Within- and between-assay CVs for apo B/A-I ratios were less than 5.5% and 7.2%, respectively. The apo B/A-I ratio was influenced by length and temperature of storage. In results for 121 venous blood samples, the apo B/A-I ratios in dried blood spots correlated well with those in serum (r = 0.92) and correlated somewhat with the ratios for low-density lipoprotein/high-density lipoprotein cholesterol in serum (r = 0.87). Of these specimens, 68 were from patients with known familial hypercholesterolemia, all of whom had an apo B/A-I ratio greater than 0.90. We think this method will be of value for detecting familial hypercholesterolemia and possibly familial hyperapobeta- and hypoalphalipoproteinemia.