Advanced Sperm Tests

When a couple is affected by infertility, one of the first tests a doctor will recommend is a semen analysis for the man, in addition to various tests for the woman. The purpose of a semen analysis is to count the number of active sperm cells in his ejaculate, and assess their motility (ability to swim and penetrate an egg) and their morphology (whether or not they have a healthy shape and structure). Several advanced sperm testing procedures may be used to assess sperm health during a semen analysis.

Sperm Agglutination

This involves putting a fresh semen sample under a microscope to check whether or not the sperm cells in the sample are clumping together. Sperm cells that clump together will have difficulty swimming through the cervical mucus at the entrance to a woman's uterus, and therefore may struggle to reach an egg inside a woman's body. Cells can clump together by becoming attached to one another head-to-head or tail-to-tail. Men whose sperm cells clump may be affected by an inflammatory disorder or by an immunological response (basically an allergic reaction to their own sperm cells). They may also have higher-than-average levels of white blood cells in their semen.

Sperm Penetration Assay

This male fertility test is also known as the "hamster zona-free ovum test" and the "hamster test." Not surprisingly, this is because the test involves the use of egg cells from a female hamster. In a laboratory, a man's sperm cells are brought into contact with hamster eggs, and the number of sperm cells who manage to penetrate the eggs are counted. This test is rarely used anymore.

Hemizona Assay

In this laboratory test, a human egg cell is cut in half and the sperm cells are given a chance to penetrate its outer layer, which protects the egg and is therefore the most difficult for sperm cells to pass through. The number of sperm cells which manage to penetrate are counted. The fact that the human egg is cut in half means that there is no chance of fertilization actually taking place - therefore no embryo and no baby can possibly be created during this test.

Acrosome Test

The acrosome reaction is a chemical process which the heads of sperm cells go through when they come into contact with an egg cell. This process enables to the sperm cells to penetrate the egg's outer layer by dissolving part of it. The acrosome itself is the front part of the sperm cell's head. This test aims to determine whether or not a man's sperm cells have this ability.

Hypo-Osmotic Swelling

This fertility test assesses the health of the tails of sperm cells, as well as the sperm cells' ability to penetrate an egg. The sperm cells are immersed in a sugar and salt solution. The tails of healthy sperm cells react to this by swelling up. If the tails are not healthy, or if the sperm cells are not living, nothing will happen. A man's sperm health is considered normal if around 50% of the sperm cells in his sample have swollen tails.


The outcomes of all or some of these tests are combined in the semen analysis results presented to the patient. If it emerges from this testing process that his sperm health is poor, there are still ways to help him father a child, such as IUI or IVF treatment.

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