Escherichia coli O157 serology: false-positive ELISA results caused by human antibodies binding to bovine serum albumin.

An analysis of farm workers and rural dwellers for serum antibodies to the lipopolysaccharide (LPS) of Escherichia coli O157 detected sera with antibodies binding to bovine serum albumin (BSA) by ELISA. These antibodies were not specific for BSA when examined by immunoblotting, and the ELISA values were reduced to a background level when plates were blocked with normal rabbit serum.