Radioimmunoassay for detection of antibody to hepatitis A virus. Results of clinical evaluation.

The performance of a solid-phase radioimmunoassay (HAVAB) for the detection of antibody to hepatitis A virus (HAV) was evaluated in clinical studies. The procedure was reproducible by eight investigators, and laboratory-to-laboratory variations were minimal. The sensitivity of the test was about equal to or slightly greater than that of immune adherence hemagglutination (IAHA) for detecting antibody in serum, but IAHA gives somewhat higher titer values than HAVAB. A survey of the incidence of anti-HAV in selected populations revealed an overall frequency of 48% and a correlation with age and lower socioeconomic status. The specificity of the test was demonstrated with specimens from patients who had clinical hepatitis A. Seroconversion to anti-HAV positivity was demonstrated with HAVAB to coincide with onset of illness, about two to three weeks earlier than it was detected by IAHA. HAVAB provided a convenient test for demonstrating the immune status of subjects, and was useful as an aid in diagnosing hepatitis A.