The effect of toilet sanitizers and detergents on immunological occult blood tests.

Effects of time-releasing toilet bowl sanitizers and their main constituents, detergents, on immunological fecal occult blood tests were examined. Six kinds of toilet sanitizers and 19 kinds of detergents were included. Patients' fecal samples and hemoglobin solutions were measured by means of quantitative immunological fecal occult blood tests after being mixed with sanitizer or detergent solutions. Marked reduction in hemoglobin concentration or antigenicity was observed after the addition of sanitizers or detergents at a final concentration of 0.5 g/l. Most of these inhibitory reactions were dose dependent. In contrast with the immunological method, the chemical method using o-tolidine and guaiac were not affected by the detergents tested. In sampling feces for immunological fecal occult blood tests, contact of samples with sanitizer solutions should be avoided.