ACROBEADS TEST AS A PREDICTOR OF FERTILIZATION IN-VITRO

PROBLEM: To determine whether the results of the Acrobeads test, which measures the expression of the complement regulator molecule CD46 on the inner acrosomal membrane following the acrosome reaction, accurate ly identifies semen specimens that will exhibit reduced or failed fert ilization following conventional IVF insemination. METHOD: The Acrobea ds test was performed on semen specimens from 97 consecutive patients preparing to undergo an IVF cycle utilizing a standardized inseminatio n protocol. Motile sperm populations were examined at 6 h and 24 h pos t-isolation for sperm-bead agglutination. Results of the Acrobeads tes t were compared to that of TRITC-PSA staining in matched specimens to directly measure the spontaneous loss of acrosome content. The percent ages of TRITC-PSA-negative sperm were determined in freshly isolated m otile populations and in duplicate aliquots incubated 18 to 20 h under sperm capacitating conditions. The relationship between the results o f both analyses estimating spontaneous acrosome reactions and the rate of fertilization of metaphase II oocytes was examined. RESULTS: The A crobeads score did not correlate significantly with the rate of fertil ization by insemination at 6 h or at 24 h. The negative predictive val ue of this test was 21.4%. There was no correlation between the Acrobe ads score and the percentage of sperm undergoing a spontaneous acrosom e reaction as detected by TRITC-PSA labeling. In contrast, the increme nt increase in the percentage of spontaneous acrosome reactions as qua ntified by TRITC-PSA staining was correlated with the fertilization ra te. CONCLUSIONS: Contrary to previous reports, our prospective, double -blinded study failed to demonstrate that the Acrobeads test can accur ately predict fertilization outcome in IVF. Therefore, the routine use of this test to screen patients prior to an IVF cycle in order to sel ect appropriate treatment (i.e., ICSI) cannot be recommended.