ROUTINE ANTENATAL SCREENING FOR HEPATITIS-B USING POOLED SERA - VALIDATION AND REVIEW OF 10 YEARS EXPERIENCE

Aims-To validate the sensitivity of universal antenatal screening for hepatitis B surface antigen (HBsAg) by testing pools of 10 sera, and t o review 10 years' experience using this method, Methods-66 945 antena tal patients were tested between 1986 and 1994 using the pooled method . All sera from 1996 (n = 6050) were retrieved and retrospectively tes ted individually. An in vitro determination of the effect of pooling o n sensitivity was performed by checkerboard neutralisation assay. Resu lts-26 KBsAg positive women were detected by universal screening over 10 years; 12 had non-European surnames and five had known risk factors for hepatitis B infection. High titre anti-HBs sera in the pool reduc ed the sensitivity of the HBsAg assay, though the effect was only sign ificant at low levels of HBsAg carriage, Conclusions-The prevalence of hepatitis B is extremely low in the antenatal population served by Pl ymouth PHL, Pooling is unlikely to reduce sensitivity enough to lead t o significant preventable vertical transmission, and is a cost-effecti ve and valid strategy in areas of low seroprevalence.