How is it used?
Semen analysis is used to determine whether a man might be infertile (unable to get a woman pregnant). 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 conceive 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. To see an image of a normal sperm see the MedlinePlus Encyclopedia page on sperm.
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 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).