Hepatitis B surface antigen in notified cases of viral hepatitis

Eighty-five patients notified to the local medical officer of health as infectious or serum hepatitis during the period 1 September 1974-1 September 1975 were investigated by questionnaire. Serum from 73 cases was tested for the presence of HBsAg. Sixteen cases were notified as serum hepatitis but only 13 were shown to have HBsAg in their serum. Sixty-eight cases were notified as infectious hepatitis and 21 HBsAg positive cases were found amongst the 57 sera tested. Two-thirds of the HBsAg positive cases were not suspected clinically. The epidemiology of hepatitis in Christchurch is discussed and suggestion is made that all notified cases of hepatitis should have blood tested for HBsAg.