A study of the fertilizing capacity of human spermatozoa: the hamster test.

There are many reports on the hamster test as a test of the fertilizing capacity of human spermatozoa, and its usefulness is widely known. However, the results obtained cannot be simply compared because of the different conditions used for the test. According to our studies, the type of serum albumin present in incubated specimens was considered to affect particularly the rate of sperm penetration. Penetration rates of human spermatozoa were determined under the most appropriate test conditions using good-quality human serum albumin. The penetration rate was 69 +/- 9% (range: 33-98%) in men whose fertility had been confirmed within 2 years before test, while it was 34 +/- 5% (range: 0-100%) in infertile men, showing a significantly low rate. Eight of nine men who achieved fertilization within one year after the examination showed a penetration rate of over 30%. The remaining one showed a rate of 16%, but he underwent surgery for varicocele and treatment with methylcobalamin and Hochuekkito after the test. Men thus seem difficult to conceive women when the penetration rate of their spermatozoa is below 30%.