Reliability and accuracy of the zona-free hamster ova assay in the assessment of male fertility.

The efficacy of the zona-free hamster ova assay in assessing male fertility was studied in 22 men of proven fertility, 16 of unproven fertility, and 31 who were members of infertile couples. The mean hamster ova penetration rates were significantly higher in males of proven fertility (34%) and unproven fertility (30%) than in infertile males (11%). Sperm from 21 of 22 men of proven fertility penetrated greater than 15% of ova; one man had a zero penetration rate. Sperm from 8 of 16 men of unproven fertility and 24 of 31 men of infertile couples penetrated less than 15% of ova. There was no correlation between penetration rates and any of the traditional measures of semen analysis. Two assays were performed on every male and six assays were performed on six males. There was good interassay reliability in all 69 males (r = 0.86) and in the six males with six tests (r = 0.97). The mean interassay variation was 8.6%.