Immunochemical methods for quantification of apolipoprotein A-IV.

Several methods are available for the immunoassay of apoA-IV levels in plasma, or lipoproteins. The method of choice depends on the question being asked. If sensitivity is not a major determinant, simple immunoelectrophoresis is probably sufficient. To determine apoA-IV levels in plasma or lipoprotein fractions, either radioimmunoassay or a competitive ELISA is indicated. The competitive ELISA described above, however, offers sensitivity as well as rapidity and case of performance. When very low levels of apoA-IV are present (such as those produced by cultured cells), the higher sensitivity of the sandwich ELISA may be required.