A semen analysis is a test to evaluate a man's fertility.

A semen sample will be obtained. Semen is the thick, white, sperm-containing fluid excreted during ejaculation. The method of sample collection should be discussed with the health care provider.

The sample may be obtained by masturbation into a sterile container. It may also be achieved by intercourse using a special condom supplied by the health care provider. The sample must be analyzed within 2 hours of the collection. The earlier the sample is analyzed the more reliable the results are.

There should be no sexual activity that causes ejaculation for 2 to 3 days before the test.

If the man is uncomfortable about how the sample is to be taken, this should be discussed with the health care provider.

The test is performed if the patient's fertility is in question. It is helpful in determining if there is a problem in sperm production or quality of the sperm as a cause of infertility. The test may also be used after a vasectomy to make sure there are no sperm in the semen.

The semen is analyzed for the volume; number and structure of the sperm; sperm movement; and the fluid thickness, acidity, and sugar content.

Values may vary from laboratory to laboratory. The most common normal values are listed below.

The normal volume varies from 1.5 to 5.0 milliliter per ejaculation. The sperm count varies from 20 to 150 million sperm per milliliter. At least 60% of the sperm should have a normal shape and show normal forward movement (motility).

If the sperm count is very low or very high there is a likelihood of being less fertile. The percent of normal sperm has an effect on infertility. The acidity of the semen and the presence of white blood cells (suggesting infection) may influence fertility. The use of many recreational and prescription drugs, alcohol, and tobacco use may affect fertility.

Additional conditions under which the test may be performed:

• Klinefelter's syndrome

There are no risks.

Approximately half of couples unable to have children have a male infertility problem. One of the first tests done to evaluate a man's fertility is the semen analysis.

There are many unknowns in male infertility. The results from the test may fail to explain the cause. If a low sperm count or abnormal semen is found, further testing may be required.