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Sperm Penetration Tests

Sperm Penetration Tests

Test Overview

Sperm penetration tests check to see if sperm can move through cervical mucus or join with (fertilize) an egg. These tests may be done when you're having trouble getting pregnant (infertility).

There are different sperm penetration tests.

  • The sperm mucus penetration test checks if 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 checks if sperm can join with an egg. (This is also called the hamster zona-free ovum test or hamster test.) Sperm are mixed with hamster eggs in a laboratory. The number of sperm that penetrate the egg is measured. This test is not done often. But it may be done at special fertility centers that do in vitro fertilization.


Sperm mucus penetration test

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.

There may be a problem with the partner's sperm 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.

There may be a problem with the woman's mucus if neither the partner's nor the donor's sperm penetrate the cervical mucus.

Sperm mucus penetration testfootnote 1


Sperm penetrate the cervical mucus and move through it easily.


Sperm can't penetrate the cervical mucus, or they clump together in the mucus. Clumping may mean that the woman or man has formed 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. This can vary from lab to lab. Talk with your doctor to find out if your results are normal.

Sperm penetration assay (SPA)


Sperm penetrate the hamster egg.


Sperm can't penetrate the hamster egg.



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


Current as of: February 11, 2021

Author: Healthwise Staff
Medical Review:
Sarah Marshall MD - Family Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Femi Olatunbosun MB, FRCSC - Obstetrics and Gynecology

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