Sperm acrosin levels in semen: comparison between ACCU-SPERM and Kennedy's methods.

The purpose of this experiment was to evaluate the accuracy, specificity, and sensitivity of a new acrosin activity assay, ACCU-SPERM, and to correlate these results with the original Kennedy method. Thirty-nine specimens (26 patients and 13 donors) of 54 (72%) were found to be in the normal range (> 25 microIU acrosin/10(6) sperm) by the Kennedy method; the other 15 specimens were in either the indeterminate or subfertile range (< 14 microIU). However, according to the ACCU-SPERM method, (normal: 6.6-27 AAI; infertile: < 3.6), 90% of specimens (49 of 54) whose acrosin activity was measured were in the subfertile or infertile range. Similarly, only 28% (4 of 14) of donors in the ACCU-SPERM method were in the normal range in contrast to the 93% (13 of 14) in Kennedy. After calculating the ACCU-SPERM normal range in our laboratory using the linear regression curve between the acrosin values generated by the Kennedy and ACCU-SPERM methods, we again compared results of the two methods. The new normal range of > 1.82 AAI in ACCU-SPERM corresponded to > 25 microIU in the Kennedy method; similarly a value of < 1.35 AAI in ACCU-SPERM corresponded to < 14 microIU in the Kennedy technique. Analysis of the results generated by the two methods revealed a poor correlation with a positive concordance of 51% and a negative concordance of 50% in both assays. These results strongly suggest that the ACCU-SPERM method for measurement of acrosin activity is not a reliable assay.