Hepatitis B Surface Antigen in Environmental Samples from Hemodialysis Units

Abstract

For assessment of environmental contamination with hepatitis B surface antigen (HB_s Ag), the presence of blood and of HB_s Ag was determined in samples from two completely separated hemodialysis units. Samples from mucosal and skin surfaces and samples of saliva from patients were also investigated. The surfaces of both units were divided into epidemiological categories to determine the distribution of environmental contamination with HB_s Ag. HB_s Ag was determined by radioimmunoassay. Oral samples from all patients seropositive for HB_s Ag were positive for HB_s Ag. The rectum and the skin were positive in three instances. The presence of blood did not coincide with HB_s Ag. In the unit in which HB_s Ag-positive patients were treated, 4.3% of the total samples were HB_s Ag-positive. Of the samples that were free of blood, 1.5% were HB_s Ag-positive, whereas 18.5% of the bloodcontaminated samples contained the antigen. HB_s Ag-positive samples were taken from surfaces in the immediate environment of HB_s Ag-positive patients, as well as from surfaces with which patients had no direct physical contact. The data lead to the conclusion that spilled blood and hemodialysis equipment are not the only sources of contamination. This fact implies that HB_s Ag-positive patients undergoing hemodialysis should be completely separated from HB_s Ag-negative patients.