At a glance

Also known as

Sperm count; seminal fluid analysis

Why get tested?

To investigate the health of your reproductive organs if your partner is having trouble becoming pregnant, or after a vasectomy to determine if the operation was successful

When to get tested?

When you think you might have a fertility problem or after you have had a vasectomy

Sample required?

A semen sample collected in a sterile container provided by the lab

What is being tested?

A semen analysis measures the quantity and quality of both the liquid portion, called semen, and the microscopic moving cells called sperm. Semen is the turbid, whitish substance that is released from the penis during ejaculation. Sperm are the cells in semen with a head and a tail that enables them to travel to the egg. A sperm contains one copy of each chromosome (all of the male’s genes) and fuses with the female’s egg, resulting in fertilisation.

A typical semen analysis could measure:

  • the volume of semen
  • the semen consistency (thickness)
  • sperm concentration,
  • total number of sperm
  • sperm motility (the percentage that are able to move, as well as how vigorously and straight the sperm move)
  • the number of normal and not normal (defective) sperm
  • coagulation and liquefaction
  • fructose (a sugar in semen)
  • pH (acidity)
  • the number of immature sperm, and
  • the number of white blood cells (cells that indicate infection).

Additional tests may be performed if semen is abnormal, such as a test for sperm antibodies. If assisted reproductive technology is contemplated, for example, in vitro fertilisation (IVF), sperm function tests may also be performed. Sometimes a test called cryosurvival is done to see how well semen will survive frozen for periods of time, if a couple would like to store sperm for future pregnancies.

How is the sample collected for testing?

Most labs require samples to be collected on-site as the semen needs to be examined within one hour after ejaculation. Semen is collected in a private area, usually a bathroom. The man masturbates and collects the semen in a jar. Some men, for religious or other reasons, might want to collect semen during the act of intercourse, using a condom. If this is the case, the doctor should provide the condom or sheath because lubricated condoms can affect test results.

The Test

How is it used?

Semen analysis is used to determine whether a man might be infertile (unable to concieve a child with his partner). The semen analysis tests many aspects of the semen and sperm. Semen analysis to determine fertility should be performed on a minimum of two samples at least seven days apart over a period of two to three months because some medical conditions can affect sperm levels.

The semen analysis can also be used to count sperm after a man has a vasectomy. If there are still a lot of sperm present in the semen, the man and his partner will have to take precautions so that his partner will not become pregnant. He will have to return for one or more sperm counts until the sperm are cleared from his sample(s).

When is it requested?

Semen analysis is recommended following a vasectomy or when your doctor thinks that you might have a fertility problem. At least 20% of married couples experience problems conceiving, and this is due to the male partner in about 40% of cases. Male infertility has many causes and some of these, such as varicocoele (hardening of the veins draining the testes), can be treated successfully. If male factors are involved, analysis of the semen is necessary to determine the feasibility of using IVF to facilitate pregnancy.

What does the test result mean?

The typical volume of semen collected is around a teaspoonful (2-6 millilitres) of fluid. Less semen would indicate fewer sperm, which would affect fertility. More semen indicates too much fluid, which would dilute the sperm, also impeding fertility.

Sperm concentration (also called sperm density) is measured in millions of sperm per millilitre of semen. Levels greater than or equal to 20 million per millilitre (and more than 80 million sperm in one ejaculation) are considered normal. The fewer sperm a sample has, the less chance a man has of getting his partner pregnant. A man who has just had a vasectomy would want to have no sperm in his sample.

The percentage of moving sperm in a sample is known as its 'motility'. The more slowly moving or immobile sperm in a sample, the less likely it is that a man could concieve a child with his partner. The progression of the sperm is rated on a basis from zero (no motion) to 3 or higher for sperm that move in a straight line with good speed. If less than half of the sperm are moving, a stain is used to identify the percentage of dead sperm. This is called a 'sperm viability test'.

Morphology analysis is the study of the size, shape and appearance of the sperm cells. The analysis evaluates the structure of 200 sperm and any defects are noted. The more abnormal sperm that are present, the lower the likelihood of fertility.

Is there anything else I should know?

To give sperm a chance to replenish, a man should abstain from ejaculating for two to four days before the sample is collected. Follow the instructions that are provided to you.

Sperm are very temperature-sensitive. If collection is done at home, the sample should be kept at room temperature (21°C/70°F) at all times. Never refrigerate the sample or try to warm it to body temperature.

Several factors can affect the sperm count and other semen analysis values. A man may have a lower sperm count if he has physical damage to the testicles, has gone through radiation treatment of his testicles, or has had exposure to certain drugs (such as azathioprine). A man with a higher level of oestrogens may have a lower sperm count.

Some of the common causes of male infertility are extremely high fever, testicular failure (failure of the testicles to produce sperm), obstruction of the tubes that carry semen to the penis and a less than normal amount of sperm in the sample (oligospermia).

Common Questions

What are the best indicators of fertility in a semen analysis, out of all of the many things that are checked?

Motility (which indicates the percentage of living sperm) and morphology (normal shape of the sperm) are most closely linked with good fertility rates.

I had good motility on my first sperm sample, but later it was very low. What could cause that?

If you had a good motility on the first reading, you may have a low sperm count later because of a genital infection or because of an inflamed prostate gland.

Shouldn’t they check my wife’s fertility first?

When a couple cannot become pregnant, it is much easier, less invasive and less expensive for the man to be tested first. A man requires only semen analysis and the samples can be collected and tested very quickly. If the man’s semen is normal, then it makes sense to move ahead with the more invasive and expensive tests for female infertility.

Last Review Date: April 12, 2010