An improved sensitive assay method for the heterogeneity of alpha-foetoprotein: possible application for early differential diagnosis.

A combination of lectin-affinity electrophoresis and antibody-affinity blotting was used for the qualitative determination of molecular species of alpha-foetoprotein. Concanavalin A and erythrophytohaemagglutinin were used as lectins. This method was able to quickly discriminate between the molecular species of alpha-foetoprotein of recurrent ovarian yolk sac tumour and those of non-malignant liver diseases and cord sera at term, using only 3 microliters of sera containing 200 micrograms/l of alpha-foetoprotein. The results indicate that this assay method might be useful for the differential diagnosis of recurrent yolk sac tumour from drug- or blood transfusion-induced liver diseases and for the monitoring of the serum alpha-foetoprotein level of patients with yolk sac tumour producing less than 200 micrograms/l of alpha-foetoprotein.