Direct antisperm antibodies using enzyme immunoassay or immunobeads. A prospective cohort comparison

An enzyme immunoassay for detecting antisperm antibodies directly on sperm was compared to immunobeads in a prospective cohort design. In a series of 112 divided ejaculates evaluated for assisted reproductive technologies, there was moderate overall agreement (kappa = .64) between the methods. All ejaculates positive by immunobeads were also positive by enzyme immunoassay. The enzyme immunoassay could be performed even on oligospermic specimens. When both assays could be employed, the enzyme immunoassay was positive more often (P = .001). Positive specimens by enzyme immunoassay often bound IgA-class antibodies alone, without IgG. Enzyme immunoassay results may represent false-positive results or a new, lower threshold for antibody detection.