Semen Analysis

A semen analysis measures the amount of semen a man produces and determines the number and quality of sperm in the semen sample.

A semen analysis is usually one of the first tests done to help determine whether a man has a problem fathering a child (infertility). A problem with the semen or sperm affects more than one-third of the couples who are unable to have children (infertile).

Tests that may be done during a semen analysis include:

Volume. This is a measure of how much semen is present in one ejaculation.

Liquefaction time. Semen is a thick gel at the time of ejaculation and normally becomes liquid within 20 minutes after ejaculation. Liquefaction time is a measure of the time it takes for the semen to liquefy.

Sperm count. This is a count of the number of sperm present per milliliter (mL) of semen in one ejaculation.

Sperm morphology. This is a measure of the percentage of sperm that have a normal shape.

Sperm motility. This is a measure of the percentage of sperm that can move forward normally. The number of sperm that show normal forward movement in a certain amount of semen can also be measured (motile density).

pH. This is a measure of the acidity (low pH) or alkalinity (high pH) of the semen.

White blood cell count. White blood cells are not normally present in semen.

Fructose level. This is a measure of the amount of a sugar called fructose in the semen. The fructose provides energy for the 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.

How To Prepare

You may be asked to 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.

Be sure to tell your health professional about any medications or herbal supplements you are taking.

How It Is Done

You will need to produce a semen sample, usually by ejaculating into a clean sample cup. You can do this in a private room or in a bathroom at your health professional's office or clinic. If you live close to your health professional's office or clinic, you may be able to collect the semen sample at home and then transport it to the office or clinic for testing.

The most common way to collect semen is by masturbation, directing the semen into a clean sample cup.

You can collect a semen sample during sex by withdrawing your penis from your partner just before ejaculating (coitus interruptus). You then ejaculate into a clean sample cup. This method can be used after a vasectomy to test for the presence of sperm, but other methods will likely be recommended if you are testing for infertility.

You can also collect a semen sample during sex by using a condom. If you use a regular condom, you will need to wash it thoroughly before using it to remove any powder or lubricant on it that might kill sperm. You may also be given a special condom that does not contain any substance that kills sperm (spermicide). After you have ejaculated, carefully remove the condom from your penis. Tie a knot in the open end of the condom and place it in a container that can be sealed in case the condom leaks or breaks.

How It Is Done continued...

If you collect the semen sample at home, the sample must be received at the laboratory or clinic within 1 hour. Keep the sample out of direct sunlight and do not allow it to get cold or hot. If it is a cold day, carry the semen sample container against your body to keep it as close to body temperature as possible. Do not refrigerate the semen sample.

Since semen samples may vary from day to day, 2 or 3 different samples may be evaluated within a 3-month period for accurate testing.

A semen analysis to test the effectiveness of a vasectomy is usually done 6 weeks after the vasectomy.

How It Feels

Producing a semen sample does not cause any discomfort. However, you may feel embarrassed about the method used to collect it. If masturbation is against your religious beliefs, discuss alternate methods of collection with your health professional.

Risks

There are no risks associated with collecting a semen sample.

Results

A semen analysis measures the amount of semen a man produces and determines the number and quality of sperm in the semen sample. Results of a semen analysis are usually available within a day. Normal values may vary from lab to lab.

Semen analysis

Semen volume

Normal:

1.0–6.5 milliliters (mL) per ejaculation

Abnormal:

An abnormally low or high semen volume is present, which may sometimes cause fertility problems.

Liquefaction time

Normal:

Less than 60 minutes

Abnormal:

An abnormally long liquefaction time is present, which may indicate an infection.

Sperm count

Normal:

20–150 million sperm per milliliter (mL)

0 sperm per milliliter if the man has had a vasectomy

Abnormal:

A very low sperm count is present, which may indicate infertility. However, a low sperm count does not always mean that a man cannot father a child. Men with sperm counts below 1 million have fathered children.

Sperm shape (morphology)

Normal:

At least 70% of the sperm have normal shape and structure.

Abnormal:

Sperm can be abnormal in several ways, such as having two heads or two tails, a short tail, a tiny head (pinhead), or a round (rather than oval) head. Abnormal sperm may be unable to move normally or to penetrate an egg. Some abnormal sperm are usually found in every normal semen sample. However, a high percentage of abnormal sperm may make it more difficult for a man to father a child.

Sperm movement (motility)

Normal:

At least 60% of the sperm show normal forward movement.

At least 8 million sperm per milliliter (mL) show normal forward movement.

Abnormal:

Sperm must be able to move forward (or "swim") through cervical mucus to reach an egg. A high percentage of sperm that cannot swim properly may impair a man's ability to father a child.

Semen pH

Normal:

Semen pH of 7.1–8.0

Abnormal:

An abnormally high or low semen pH can kill sperm or affect their ability to move or to penetrate an egg.

White blood cells

Normal:

No white blood cells or bacteria are detected.

Abnormal:

Bacteria or a large number of white blood cells are present, which may indicate an infection.

Fructose level

Normal:

300 milligrams (mg) of fructose per 100 milliliters (mL) of ejaculate

Abnormal:

The absence of fructose in the semen may indicate that the man was born without seminal vesicles or has blockage of the seminal vesicles.

Certain conditions may be associated with a low or absent sperm count. These conditions include orchitis, varicocele, Klinefelter syndrome, radiation treatment to the testicles, or diseases that can cause shrinking (atrophy) of the testicles (such as mumps).

If a low sperm count or a high percentage of sperm abnormalities are found, further testing may be done. Other tests may include measuring hormones, such as testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), or prolactin. A small sample (biopsy) of the testicles may be needed for further evaluation if the sperm count or motility is extremely low.