A semen analysis evaluates certain characteristics of a man's semen and the sperm contained in the semen. It may be done while investigating a couple's infertility or after a vasectomy to verify that the procedure was successful. The tests done on a sample of semen, checks the volume, liquefaction time and pH value of the semen; count, morphology and motility of the sperm; white blood cell count and sugar level of the semen.

How to collect the semen sample

Avoid any sexual activity that results in ejaculation for 2 to 5 days before a semen analysis. This helps ensure that your sperm count will be at its highest, and it improves the reliability of the test. If possible, do not avoid sexual activity for more than 1 to 2 weeks before this test, because a long period of sexual inactivity can result in less active sperm.

You may be asked to avoid drinking alcohol for a few days before the test.

A semen sample will be collected by asking your husband to masturbate directly into a special sterile container. There is no point trying to collect a sample by withdrawal at intercourse as some of the initial part of the ejaculate is lost. Transferring a sample from a condom does not help either as most sheaths these days contain a potent spermicide. Some specialists recommend that you abstain from intercourse for a few days before the sample is collected. However, others feel that it is better to follow your normal pattern of intercourse. The semen sample should be  kept warm and should be delivered to the laboratory for testing within one hour of production.  After the sample volume has been measured, the following calculations are carried out.

• The number of sperm per milliliter (ml).
• The percentage of sperm showing normal forward progressive movements (motility).
• The percentage of abnormal sperm.

Why It Is Done

A semen analysis is done to determine whether:

• A man has a reproductive problem that is causing infertility.
• A vasectomy has been successful.
• The reversal of a vasectomy has been successful.

What are the indications for normal semen

A normal semen analysis will show:

• A volume greater than 2 ml.
• A count of more than 30 million sperm per ml
• A motility greater than 60% within one hour of production 
• An abnormality rate of less than 25%.
  

What Affects the Test

Factors that can interfere with your test or the accuracy of the results include:

• Medicines, such as cimetidine (Tagamet), male and female hormones (testosterone, estrogen), sulfasalazine, nitrofurantoin, and some chemotherapy medicines.
• Caffeine, alcohol, cocaine, marijuana, and smoking tobacco.
• Herbal medicines, such as St. John's wort and high doses of echinacea.
• A semen sample that gets cold. The sperm motility value will be inaccurately low if the semen sample gets cold.
• Exposure to radiation, some chemicals (such as certain pesticides or spermicides), and prolonged heat exposure.
• An incomplete semen sample. This is more common if a sample is collected by methods other than masturbation.
• Not ejaculating for several days. This may affect the semen volume.