The process can help doctors to determine the underlying cause of a person's inability to conceive, or it may confirm the outcome of a vasectomy.
A sperm analysis tests for several markers of sperm health, including:
- the number of sperm in 1 milliliter (ml) of semen
- the size and shape of the sperm
- the ability of the sperm to move correctly
In this article, we describe the purpose and procedure involved in sperm analysis, and we explain what the results may mean.
Why is sperm analysis done?
A sperm analysis can help a doctor diagnose fertility problems.
People may require a sperm analysis for different reasons. Some individuals or couples will request a sperm analysis if they are having difficulty conceiving.
In couples that have been unable to conceive, some estimates suggest that there is a male factor present in 40 to 50 percent of cases.
Up to 2 percent of men demonstrate issues with their sperm, resulting from one or a combination of:
- low sperm count in a sample of semen
- poor sperm movement, known as motility
- abnormal sperm size and shape, known as morphology
People may also have a sperm analysis to check if a vasectomy was successful. A vasectomy is a surgical procedure that doctors carry out for permanent male sterilization.
Following a vasectomy, doctors typically recommend regular sperm analyses for several months to ensure there are no sperm remaining in the semen.
How to obtain a sperm sample
Usually, a doctor will require a person to provide a semen sample while in the doctor's office.
The most common way to collect a sample is for a person to masturbate and ejaculate into a sterile cup. The doctor provides a private room for a person to do this.
In some cases, a person can collect the semen sample at home. A doctor can provide a special condom that allows a person to collect a semen sample during sexual activity.
Otherwise, a doctor may recommend that the person ejaculates into a collection cup while at home.
When collecting a sample at home, people must remember to keep it at room temperature and bring it to the laboratory within a short timescale after collection.
To make sure that the sample is usable, the doctor may require that a person:
- abstains from sex or masturbation for several days before the test
- does not avoid ejaculation for more than 14 days before the test
- avoids alcohol, caffeine, and marijuana before the sperm analysis
- does not use lubricants when collecting the sample
- informs the doctor of any medications or herbal remedies they are taking, before giving a sample
- avoids providing a sample when unwell or stressed
The American Association for Clinical Chemistry recommends that medical professionals carry out 2 or more separate sperm analyses within 2- to 3-week intervals.
As sperm profiles can vary from day-to-day, an average of these results may give the most accurate picture of sperm health.
What do the results mean?
The results of a sperm analysis should be ready within a few days.
A sperm analysis looks at several factors when considering the health of the sperm. We discuss these factors and their results below.
Sperm count or concentration
A sperm analysis can help identify issues with sperm count, motility, or shape.
Sperm count refers to the number of sperm that are present in 1 ml of semen. World Health Organization (WHO) guidelines suggest that a normal sperm count is at least 15 million per ml or no fewer than 39 million sperm per sample.
Home sperm analysis kits usually only test for sperm count. As this is just one aspect of male fertility, it is important that people see their doctor and get comprehensive sperm analysis to check for other factors affecting their sperm.
Sperm motility is the ability of the sperm to move efficiently. Low motility can reduce the sperm's capacity to move through the female reproductive system to fertilize the egg.
In a typical sample, at least 50 percent of the sperm will demonstrate normal motility.
Morphology refers to the size and the shape of the individual sperm. Normal sperm have a long tail and oval-shaped head. Abnormally sized or shaped sperm can have difficulty reaching, penetrating, and fertilizing the egg.
Normal semen contains a minimum of 4 percent sperm with standard form.
Although sperm count, motility, and morphology are three of the main factors that medical professionals will check when assessing male fertility, they are not the only factors.
Other factors that doctors consider when doing a sperm analysis include:
- Volume of semen sample. This means the amount of semen a person provides in their sample. Typically, a sample is at least half a teaspoon. Less than this can suggest that there may be a blockage in the vessels through which sperm travels.
- Liquefaction. Semen normally leaves the body in a thickened state. Liquefaction time assesses how long it takes for the semen to become liquid. Failure to liquefy, or liquefying slowly, may indicate a problem.
- PH level. Having a pH that is too high (alkaline) or too low (acidic) may affect the health of the sperm and their ability to move through the female reproductive tract.
- Seminal fructose levels. Semen samples that do not contain sperm may demonstrate low levels of fructose. This suggests a problem with the function of the seminal glands.
What do abnormal results mean?
A doctor may recommend further tests to identify the cause of abnormal results.
The Centers for Disease Control and Prevention (CDC) advise that a slightly abnormal sperm analysis does not mean that a person is permanently infertile. Instead, doctors can use the results as a tool to help identify what factors are causing fertility issues.
People who receive abnormal results from a semen analysis typically undergo further testing to help identify the exact issue. In many cases, a person's fertility issues resolve with the right treatment.
Semen analysis after a vasectomy
Following a vasectomy, doctors will check a person's semen for the presence of sperm.
If the semen sample does not contain any sperm, people may be able to stop using condoms and other forms of birth control, as pregnancy is unlikely.
However, if sperm is still present, people should continue using contraceptives to prevent unwanted pregnancies. They may need further sperm analysis tests until their semen no longer shows the presence of sperm.
A sperm analysis is one of the first tests that males undergo to look for the reasons for difficulty with conceiving. People also require sperm analysis to check the success of a vasectomy.
If sperm analysis results are abnormal, a doctor will typically recommend further testing to help find the underlying cause and formulate a treatment plan.
Many cases of male infertility are treatable with lifestyle changes, medications, surgery, and other interventions. If these are unsuccessful, a doctor or fertility counselor can help people explore other options, such as donor sperm or adoption.