Serum alphafetoprotein levels in subjects infected with hepatitis B virus.

Serum alphafetoprotein (AFP) levels were measured using a sensitive radioimmunoassay in 108 hepatitis B surface antigen (HBsAg)-positive subjects and 695 controls. The concentrations were significantly higher in the HBsAg-positives. Within this group, the highest levels were found in those with active HBV infection. In those without evidence of acute infection, the levels were higher in the high-risk than in the low-risk subjects. It is concluded: 1) that measurement of serum AFP might be a useful additional index of infectivity and prognosis in HBsAg-positive subjects; and 2) that in the light of the association between chronic HBV infection, hepatocellular carcinoma, and raised AFP in non-European populations, consideration should be given to regular monitoring of AFP levels in HBsAg-positive subjects in the United Kingdom.