Some considerations of methodology and standardization of apolipoprotein A-I immunoassays

Apolipoprotein A-I (apo A-I) is the major protein of high-density lipoprotein. Compelling evidence suggests that measurement of concentrations of apo A-I in serum may be useful in predicting and assessing ischemic heart disease. The following review of methods of isolation, characterization, and assay of apo A-I has been developed to assess the possibility of standardizing apo A-I immunoassays. We consider the properties of apo A-I that have an effect on its quantification, such as self-association, polymorphism, and stability characteristics. We attempt to review critically the various methods presented, but more information about the physicochemical properties of the protein is required before definitive recommendations can be made.