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

Abstract 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 and rology 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 ≥20% of the sperm were antibody-bound, and clinically significant levels were present when ≥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 ≥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.