Hepatitis B surface antigen in environmental samples from hemodialysis units

For assessment of environmental contamination with hepatitis B surface antigen (HBS Ag), the presence of blood and of HBS 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 HBS Ag. HBS Ag was determined by radioimmunoassay. Oral samples from all patients seropositive for HBS Ag were psoitive for HBS Ag. The rectum and the skin were positive in three instances. The presence of blood did not coincide with HBS Ag. In the unit in which HBS Ag-positive patients were treated, 4.3% of the total samples were HBS Ag-positive. Of the samples that were free of blood, 1.5% were HBS Ag-positive, whereas 18.5% of the blood-contaminated samples contained the antigen. HBS Ag-positive samples were taken from surfaces in the immediate environment of HBS 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 HBS Ag-positive patient undergoing hemodialysis should be completely separated from HBS Ag-negative patients.