Serum alpha-fetoprotein: I. Evaluation of quantitative assays adapted to automated immunoassay systems.

Serum alpha-fetoprotein (s.AFP) has been established as a useful tool in monitoring of high-risk pregnancies, as an indicator of fetal neural tube defects, and has been used as an adjunct tumor marker and for monitoring therapeutic efficacy in the treatment of certain tumors. To date, the methods for measuring s.AFP are based upon the immunologic principle and are manual methods. The purpose here is to relate the evaluation of two automated systems for the assay of s.AFP. The automated systems are based upon the following immunoassay methods: a microparticle capture enzyme separation and final quantitation by reflectance fluorescence, and a solid phase 'sandwich' separation coupled with enzyme activity measurement (EIA). The reference method is a competitive binding radioimmunoassay. It has been found by us that the automated methods directly transfer analytically with the manual assay. All methods are referenced to the same standard (WHO 1st Intl. Std. for AFP 72/225).