Hepatitis B surface antigen (HBSAg) in peritoneal fluid of HBSAg carriers undergoing peritoneal dialysis

Samples of ascitic fluid and outflow dialysate were collected from HBSAg carriers undergoing peritoneal dialysis and tested for HBSAg by solid-phase radioimmunoassay. The surface antigen was detected in every sample from HBSAg carriers. This finding was not dependent upon the presence of occult blood in the sample. Surface antigen particles and possibly Dane particles were also observed in HBSAg-positive samples by immunoelectron microscopy. These results identify the outflow dialysate of HBSAg carriers undergoing peritoneal dialysis as a potential source of hepatitis B virus transmission.