Detection of antisperm antibodies in seminal plasma by flow cytometry: comparison with the indirect immunobead binding test

OBJECTIVE: To compare flow cytometry with the established indirect immunobead binding test (IBT) for the detection of antisperm antibodies in seminal plasma. DESIGN: A prospective, comparative study. SETTING: University-based andrology unit. PATIENT(S): One hundred and fifty-eight men with suspected male factor subfertility. INTERVENTION(S): Seminal plasma samples were incubated with antisperm antibody-negative donor sperm. Surface-bound antibody was detected with fluorescence-labeled antihuman antibody in the flow cytometry assay or with immunobead-labeled antihuman antibody in the IBT. MAIN OUTCOME MEASURE(S): The percentage of sperm that tested positive for surface-bound antibody was determined in the two assays. Seminal plasma was antisperm antibody-positive when > or = 20% of the sperm were antibody-bound, and clinically significant levels were present when > or = 50% of the sperm were antibody-bound. RESULT(S): Of 71 samples that were negative by the IMT, 66 (93%) also were negative by flow cytometry. Of 63 samples that had > or = 50% immunobead binding, 55 had equivalent results by flow cytometry. Overall statistical analysis showed a good correlation between the two assays. CONCLUSION(S): There is a good correlation between the indirect IBT and indirect flow cytometry for the detection of antisperm antibodies in seminal plasma.