Sperm penetration tests check to see whether a man’s sperm can move through cervical mucus and the fallopian tubes to join with (fertilize) an egg. This test is usually done when a couple is having trouble becoming pregnant (infertility).

There are different sperm penetration tests.

• The sperm mucus penetration test checks whether a man’s sperm can move through the cervical mucus. This test is not done very often because there are other fertility tests that give more information about the fertility problem.
• The sperm penetration assay (also called the hamster zona-free ovum test or hamster test) checks whether a man’s sperm can join with an egg. Sperm are mixed with hamster eggs in a laboratory. The number of sperm that penetrate the egg (sperm capacitation index) is measured. This test is done most often at special fertility centers who do in vitro fertilization.

Why It Is Done

Sperm penetration tests may be done:

• When other tests have not found a cause for infertility.
• To see how the sperm function when a semen analysis test has shown some problems, such as slow movement or the sperm look abnormal.
• To check when another test, the postcoital test, has found sperm dead or not moving in the cervical mucus.
• To test sperm before doing in vitro fertilization.

How To Prepare

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean.

Sperm mucus penetration test

For women, this test must be done during ovulation. Follow your doctor’s instructions for checking the level of luteinizing hormone (LH) in your urine. When you check your LH level, do the urine test in the mid- to late morning, and do not drink any fluids that morning until you have done the test. If your test shows that you are ovulating, call for a doctor’s visit for the next day.

For men, the semen sample is collected after the cervical mucus sample is taken. You should not release your sperm (ejaculate) for 2 days before the test. It is important to not go longer than 5 days before the test without ejaculating.

How It Is Done

For the sperm mucus penetration test, samples of your cervical mucus and your partner’s semen will be collected. In the lab, the semen is added to the mucus in a tube. After 90 minutes, the distance the sperm have moved is measured.

Cervical mucus sample

A sample of cervical mucus is collected from the woman during a pelvic examination. For more information, see the medical test Pelvic Examination.

Sperm sample

A semen sample is collected by masturbation. First, you should urinate and then wash and rinse your hands and penis before collecting the semen in a sterile cup. You cannot use lubricants or condoms when collecting the sample. If you collect the sample at home, it must be taken to the lab within 30 minutes. The sample cannot be collected by having sex and then withdrawing when you ejaculate because vaginal fluid may be mixed with the sperm.

For the sperm penetration assay, a semen sample is collected by masturbation. The sperm are mixed with hamster eggs in a laboratory. The number of sperm that penetrate an egg is measured.

How It Feels

Cervical mucus sample

You may feel some pressure or mild discomfort when the speculum is put into your vagina. The speculum spreads apart the vaginal walls, allowing your doctor to look at the inside of the vagina and the cervix. The speculum may be plastic or metal and may be warmed with water or lubricated with a vaginal lubricant (such as K-Y Jelly). Try to relax your legs and hips as much as you can.

Semen sample

Collecting 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, talk with your doctor.

Risks

Usually there are no problems from having a pelvic examination to collect a sample of vaginal fluid or from collecting a semen sample.

Results

Sperm penetration tests check to see whether a man’s sperm can move through cervical mucus and the fallopian tubes to join with (fertilize) an egg.

Sperm mucus penetration test

A controlled test can see if the cervical mucus is preventing sperm penetration. This test uses donor sperm and the male partner’s sperm. Both sperm samples are added to a sample of the woman’s cervical mucus. Donor cervical mucus may also be used with the woman’s cervical mucus.

A problem with the partner’s sperm may be present if:

• The donor’s sperm penetrates the mucus but the partner’s sperm does not.
• The partner’s sperm does not penetrate the woman’s or the donor’s cervical mucus.

A problem with the woman’s mucus may be present if neither the partner’s or the donor’s sperm do not penetrate the cervical mucus.

Sperm penetration assay (SPA)

Results vary from lab to lab. Talk with your doctor about whether your results your values are normal.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• The semen sample has not been collected correctly.
• The test is done at a time when a woman is not ovulating.

What To Think About

• The sperm penetration assay test may be done before in vitro fertilization.
• A normal sperm penetration assay and a normal semen analysis mean that the sperm is of good quality for in vitro fertilization. For more information on infertility testing, see the medical test Infertility Testing.

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.

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.

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.

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.

What To Think About

• A semen sample collected at home 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.
• Consistently detecting sperm in the semen of a man who has had a vasectomy indicates that his surgery was not successful, and another form of birth control should be used to prevent pregnancy. A low number of sperm may be present in a semen sample taken initially after a vasectomy. However, sperm should not be present in subsequent samples.
• A man whose mother took the medicine diethylstilbestrol (DES) during her pregnancy with him has a greater-than-normal risk of being unable to father a child (infertile).
• Additional tests may include measuring hormone levels, such as testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), or prolactin. For more information, see the medical tests Testosterone, Luteinizing Hormone, Follicle-Stimulating Hormone, and Prolactin.
• Other fertility testing, including sperm penetration, the presence of antisperm antibodies, or analysis after sexual intercourse (postcoital), may be recommended for infertility problems. For more information, see the medical test Infertility Testing.