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Sperm Penetration Tests

Test Overview

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 that 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. To help you understand the importance of this test, fill out the medical test information formmedical test information form(What is a PDF document?).

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.

Sperm penetration assay (SPA)

The sperm penetration assay only requires a semen sample to be taken.

For men, it is important that you do not release your sperm (ejaculate) for 2 days before the test. But do not go longer than 5 days before the test without ejaculating.

How It Is Done

Sperm mucus penetration test

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.

A sample of cervical mucus is collected from the woman during a pelvic examination. To learn more, see the topic Pelvic Examination.

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 semen sample at home, be sure to get it to the lab or clinic within 1 hour. Keep the sample at body temperature and out of direct sunlight. The sample cannot be collected by having sex and then withdrawing when you ejaculate because vaginal fluid may be mixed with the sperm.

Sperm penetration assay

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

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 semen sample at home, be sure to get it to the lab or clinic within 1 hour. Keep the sample at body temperature and out of direct sunlight. The sample cannot be collected by having sex and then withdrawing when you ejaculate because vaginal fluid may be mixed with the sperm.

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. But 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 mucus penetration test1
Normal:

Sperm penetrate the cervical mucus and move through it easily.

Abnormal:

Sperm cannot penetrate the cervical mucus or they clump together in the mucus. Clumping may mean that the woman or man has developed antibodies against the sperm. If the sperm antibodies are from the man's body, clumping may also be seen in his semen analysis.

 

Sperm penetration assay (SPA)

Results are based on the number of sperm that can penetrate an egg and can vary from lab to lab. Talk with your doctor about whether your results are normal.

Sperm penetration assay (SPA)
Normal:

Sperm penetrate the hamster egg.

Abnormal:

Sperm cannot penetrate the hamster egg.

 

What Affects the Test

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

  • 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. To learn more about infertility testing, see the topic Infertility Testing.

References

Citations

  1. Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.

Other Works Consulted

  • Fritz MA, Speroff L (2011). Male infertility. In Clinical Gynecologic Endocrinology and Infertility, 8th ed., pp. 1249–1292. Philadelphia: Lippincott Williams and Wilkins.
  • Lobo RA (2012). Infertility: Etiology, diagnostic evaluation, management, prognosis. In GM Lentz et al., eds., Comprehensive Gynecology, 6th ed., pp. 869–895. Philadelphia: Mosby.

Credits

By Healthwise Staff
Sarah Marshall, MD - Family Medicine
Femi Olatunbosun, MB, FRCSC - Obstetrics and Gynecology
Last Revised December 7, 2011

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