Semen Evaluation

Most men will initially be diagnosed with a potential male factor problem based on the results of an ejaculated sperm specimen.

Normal values for the sperm analysis, as defined by the World Health Organization (WHO):

Semen Analysis-WHO Minimal Standards of Adequacy

Ejaculate volume----------1.5-5.0cc (milliliters)

Sperm Concentration----->20 million sperm per cc

Motility--------------------->50%

Forward Progression------2 (scale 1-4)

Morphology----------------30% normal forms (WHO criteria)

Morphology---------------->4% normal forms (Krueger criteria)

Total Motile Count

Sometimes only one sperm parameter is abnormal and sometimes several are abnormal. An indicator useful in determining overall fertility is called the total motile count. This number represents the total number of motile sperm in the ejaculate. The total motile count is calculated thus:

Ejaculate volume X Sperm Concentration X %Motility = TMC

If the TMC is 20 million sperm or less, there is likely to be a 'significant' male factor problem. Men with a TMC consistently less than 5 million are said to have 'severe' male factor infertility.

Morphology

Another important parameter in the semen analysis is the morphology, or shape of the sperm. The shape of the sperm is a reflection of proper sperm development in the testicle, or spermatogenesis. Men with a defect in sperm maturation tend to have problems with sperm morphology and may then be at risk for failure of their sperm to fertilize their partner's eggs.

There are two methods for performing a semen analysis. Most clinical laboratories perform a crude estimation of the percentage of sperm in the ejaculated specimen that appear to have normal shape. Only specialized andrology laboratories have trained technicians that can perform a "strict" semen analysis. Only these "strict criteria" (also known as Krueger criteria) have been studied with regard to fertilization success or failure. If a man has a decreased number of normally shaped sperm on the Krueger strict morphology analysis, he is at risk of fertilization failure or at least low rates of fertilization. However, an increased number of abnormally shaped sperm with 'non-strict' criteria may indicate a fertilization problem, but to be certain this test should probably be repeated in a laboratory that performs strict analysis. Strict morphology is a useful test to perform with couples that have unexplained infertility, even if the semen analysis and non-strict morphology are otherwise normal.

Urologic Examination

Once an abnormal finding on a semen analysis is identified, the male partner should be referred to an urologist, preferably one that is sub-specialty trained in andrology (the urologist version of a reproductive endocrinologist) for an examination and a review of his medical history. Usually, a repeat semen analysis will be recommended by the urologist/andrologist as there is significant variability from specimen to specimen. The urologist will usually want to examine a urine sample to rule out infection or evidence of kidney or bladder problems.

If the size of the testicles is less than expected, the male will be tested for hormone levels of FSH (follicle stimulating hormone) and testosterone. He will also be examined to see if he might have a varicocele, a plexus of dilated veins in the scrotum that is associated with infertility. If an obstruction of the sperm collection or transport system anatomy is suspected, additional tests may be recommended.

Other Tests

Three other tests worth mentioning are the direct anti-sperm antibody test, hamster egg penetration assay and the sperm survival test. These tests are somewhat controversial in that they do not always consistently predict fertilization failure. It is well known that men who have undergone a vasectomy and a subsequent vasectomy reversal frequently develop antibodies against their own sperm. If a large number of these antibodies bind to the head of the sperm, it becomes increasingly difficult for fertilization to take place. is About 5% of men with unexplained infertility who have no prior surgery will have anti-sperm antibodies which may cause fertilization defects. Therefore, some physicians and urologists will recommend the direct anti-sperm antibody test be performed on the sperm of men who have otherwise unexplained infertility. If the sperm sample shows significant amounts of agglutination (sperm stuck to each other) this test should be performed.

The hamster egg penetration assay is a test that is still performed in some andrology laboratories. This test involves the incubation of a man's ejaculated sperm with hamster eggs. It compares the percent of sperm bound to the eggs with the results from a sperm specimen from a man with proven fertility (the control sperm). This is an expensive test with somewhat limited predictive value. That is, the results are rather poor at reliably predicting who will have fertilization problems.

The sperm survival test involves a semen analysis for count and motility, the preparation of the sperm specimen as if it might be used for an insemination and then the incubation of the sperm specimen for 24 hours. If the sperm recovery on preparation is poor or if the number of motile sperm drops off significantly over the course of the 24-hour incubation, there is some evidence that fertilization rates will be poor and ICSI may need to be performed. (Click on ICSI above for more information)