Andrology: The acrosome reaction to ionophore challenge test: assay reproducibility, effect of sexual abstinence and results for fertile men

Abstract

Since the human acrosome reaction is considered a prerequisite for normal fertilization and the spontaneous acrosome reaction rate is low, laboratory tests using calcium ionophores to induce the acrosome reaction have been devised and applied to the investigation of patients. The introduction of any new laboratory test into routine clinical practice is usually accompanied by the determination of intra- and inter-subject variability within the normal population, and the derivation of reference values to distinguish between affected and unaffected populations. The acrosome reaction to ionophore challenge (ARIC) test was evaluated and found to have (i) intra- and inter-assay coefficients of variation of 10.8 and 18.8% respectively, (ii) a high degree of intra-subject variability for three subjects studied over a 10 week period, (iii) a high degree of inter-subject variability when aliquots of 20 ejaculates of donor semen of proven fertility were tested, and (iv) no effect of length of sexual abstinence on ARIC values. The results of this study suggest that the use of fresh semen samples from subjects of proven fertility for quality control purposes in the ARIC test may be inadequate due to the high degree of intra-subject variability, and that this problem may be overcome by utilizing a frozen quality control sample. The results also suggest that an isolated negative ARIC test is not necessarily indicative of functionally incompetent spermatozoa, and highlight the importance of examination of the normal population prior to the clinical application of such a test.