Immunonephelometry of apolipoprotein A-II in hyperlipoproteinemic serum.

Immunonephelometry of apolipoprotein A-II (apo A-II) in serum requires that factors responsible for nonspecific increases of light scattering be eliminated. Complete delipidation is not necessary for immunonephelometry of apo A-II; in fact, light scattering of immunocomplexes from delipidated HDL is greater than from isolated apo A-II. Therefore, using the isolated peptide as a standard does not suffice for measurements in serum. The concentration of protein influences the development of light scattering and must be considered in standardizing this measurement.