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Home > Fitness & Health > Health Library > Semen Analysis
A semen analysis measures how much semen a man produces. It also shows the number and quality of sperm in the semen sample.
This test is usually one of the first tests done to help find out if a man has a problem fathering a child (infertility). A problem with the semen or sperm affects more than one-third of couples who are unable to have children (infertile).
Tests that may be done during a semen analysis include:
This is a measure of how much semen is present in one ejaculation.
Semen is a thick gel at the time of ejaculation. It normally becomes liquid within 20 minutes after ejaculation. Liquefaction time is the time it takes for the semen to turn to liquid.
This counts the number of sperm present per milliliter (mL) of semen in one ejaculation.
This is a measure of the percentage of sperm that have a normal shape.
This is a measure of the percentage of sperm that can move forward normally. The number of sperm that show normal forward movement in a certain amount of semen can also be measured. This is called motile density.
This is a measure of the acidity (low pH) or alkalinity (high pH) of the semen.
White blood cells are not normally present in semen.
This is a measure of the amount of a sugar called fructose in the semen. The fructose provides energy for the sperm.
A semen analysis is done to find out if:
You may be asked to avoid any sexual activity that results in ejaculation for 2 to 5 days before this test. This helps to make sure that your sperm count will be at its highest. It also makes the test more reliable. If possible, do not avoid sexual activity for more than 1 to 2 weeks before this test. A long time without sexual activity can result in less active sperm.
Do not sit in a hot tub or take a bath in hot water for 3 days before collecting the semen sample. The heat can kill sperm.
You may be asked to avoid drinking alcohol for a few days before the test.
Be sure to tell your doctor about any medicines or herbal supplements you take.
You will need to produce a semen sample. Your doctor will give you instructions on how to collect a sample for the tests that will be done.
Collecting a sample is usually done by ejaculating into a clean sample cup. You can do this in a private room or in a bathroom at your doctor's office or clinic. If you live close to your doctor's office or clinic, you may be able to collect the semen sample at home. Then you can take it to the office or clinic for testing.
If any of these methods are against your beliefs, talk with your doctor about different ways to get a sample.
If you collect the semen sample at home, the sample must be given to the lab or clinic within 1 hour. Keep the sample out of direct sunlight. And do not let it get cold or hot. If it is a cold day, carry the semen sample container against your body. This helps to keep it as close to body temperature as possible. Do not refrigerate the semen sample.
Since semen samples may vary from day to day, two or three different samples may be checked within a 3-month period. This helps to get accurate testing.
A semen analysis to test how well a vasectomy has worked is usually done 12 weeks after the vasectomy.
Getting a semen sample does not cause any discomfort. But you may feel embarrassed about the method used to collect it.
There are no known risks from having this test.
A semen analysis measures the amount of semen a man produces. It also shows the number and quality of sperm in the semen sample. Results are usually ready within a day. Normal values may vary from lab to lab.
2–5 milliliters (mL) (0.002–0.005 L in SI units) per ejaculation
An abnormally low or high semen volume is present. This may sometimes cause fertility problems.
20–30 minutes after collection
An abnormally long liquefaction time is present. This may be a sign of an infection.
20 million spermatozoa per milliliter (mL) or more
0 sperm per milliliter if the man has had a vasectomy
A very low sperm count is present. This may mean infertility. But a low sperm count does not always mean that a man can't father a child. Men with sperm counts below 1 million have fathered children.
Sperm shape (morphology)
More than 30% of the sperm have normal shape.
Kruger criteria: More than 14% of the sperm have a normal shape.
Sperm can be abnormal in several ways. They may have two heads or two tails, a short tail, a tiny head (pinhead), or a round (rather than oval) head. Abnormal sperm may not be able to move normally or to penetrate an egg. Some sperm that aren't normal are usually found in every normal semen sample. But a high percentage of abnormal sperm may make it harder for a man to father a child.
Sperm movement (motility)
More than 50% of the sperm show normal forward movement after 1 hour.
Sperm must be able to move forward (or "swim") through cervical mucus to reach an egg. A high percentage of sperm that can't swim well may make it harder for a man to father a child.
Semen pH of 7.1–8.0
An abnormally high or low semen pH can kill sperm or affect how well they can move or can penetrate an egg.
White blood cells
No white blood cells or bacteria are found.
Bacteria or a large number of white blood cells are present. This may be a sign of an infection.
Certain conditions may be linked with a low or absent sperm count. These conditions include orchitis, varicocele, Klinefelter syndrome, radiation treatment to the testicles, and diseases that can cause shrinking (atrophy) of the testicles (such as mumps).
If a low sperm count or a high percentage of abnormal sperm is found, more testing may be done. Other tests may include measuring hormones, such as testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), or prolactin. A small sample (biopsy) of the testicles may need to be checked if the sperm count or motility is extremely low.
Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Current as of:
October 8, 2020
Author: Healthwise StaffMedical Review: Sarah Marshall MD - Family MedicineAdam Husney MD - Family MedicineKathleen Romito MD - Family MedicineFemi Olatunbosun MB, FRCSC - Obstetrics and Gynecology
Current as of: October 8, 2020
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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