Test Overview
A
semen analysis measures the amount of semen a man
produces and determines the number and quality of
sperm in the semen sample.
A semen
analysis is usually one of the first tests done to help determine whether a man
has a problem fathering a child (infertility). A
problem with the semen or sperm affects more than one-third of the couples who
are unable to have children (infertile).
Tests that may be done
during a semen analysis include:
-
Volume. This is a measure of how much semen is
present in one ejaculation.
-
Liquefaction time. Semen is a thick gel at the
time of ejaculation and normally becomes liquid within 20 minutes after
ejaculation. Liquefaction time is a measure of the time it takes for the semen
to liquefy.
-
Sperm count. This is a count of the number of
sperm present per
milliliter (mL) of semen in one ejaculation.
-
Sperm morphology. This is a measure of the
percentage of sperm that have a normal shape.
-
Sperm motility. 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
(motile density).
-
pH. This is a measure of the acidity (low
pH) or alkalinity (high pH) of the semen.
-
White blood cell count. White blood cells are not
normally present in semen.
-
Fructose level. This is a measure of the amount of
a sugar called fructose in the semen. The fructose provides energy for the
sperm.
Why It Is Done
A semen analysis is done to determine
whether:
- A man has a reproductive problem that is
causing infertility.
- A
vasectomy has been successful.
- The
reversal of a vasectomy has been successful.
How To Prepare
You may be asked to avoid any sexual
activity that results in ejaculation for 2 to 5 days before a semen analysis.
This helps ensure that your sperm count will be at its highest, and it improves
the reliability of the test. If possible, do not avoid sexual activity for more
than 1 to 2 weeks before this test, because a long period of sexual inactivity
can result in less active 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 are
taking.
How It Is Done
You will need to produce a semen sample,
usually 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 and then transport it to the office or clinic
for testing.
- The most common way to collect semen is by
masturbation, directing the semen into a clean sample cup. Do not use a
lubricant.
- You can collect a semen sample during sex by withdrawing
your penis from your partner just before ejaculating (coitus interruptus). You
then ejaculate into a clean sample cup. This method can be used after a
vasectomy to test for the presence of sperm, but other methods will likely be
recommended if you are testing for infertility.
- You can also
collect a semen sample during sex by using a condom. If you use a regular
condom, you will need to wash it thoroughly before using it to remove any
powder or lubricant on it that might kill sperm. You may also be given a
special condom that does not contain any substance that kills sperm
(spermicide). After you have ejaculated, carefully remove the condom from your
penis. Tie a knot in the open end of the condom and place it in a container
that can be sealed in case the condom leaks or breaks.
If any of these methods are against your beliefs, talk with your doctor about different methods of collection.
If you collect the semen sample at home, the sample must be
received at the laboratory or clinic within 1 hour. Keep the sample out of
direct sunlight and do not allow it to get cold or hot. If it is a cold day,
carry the semen sample container against your body 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, 2 or 3 different samples
may be evaluated within a 3-month period for accurate testing.
A
semen analysis to test the effectiveness of a vasectomy is usually done 6 weeks
after the vasectomy.
How It Feels
Producing a semen sample does not cause
any discomfort. But you may feel embarrassed about the method used to collect
it.
Risks
There are no risks associated with collecting a
semen sample.
Results
A
semen analysis measures the amount of semen a man
produces and determines the number and quality of
sperm in the semen sample. Results of a semen analysis
are usually available within a day. Normal values may vary from lab to
lab.
Semen analysis
1
|
Semen
volume
|
Normal: |
2–5 milliliters (mL) (0.002–0.005 L in SI units) per
ejaculation
|
| Abnormal: |
An abnormally low or high semen volume is
present, which may sometimes cause fertility problems.
|
|
Liquefaction
time
|
Normal: |
20–30 minutes after collection
|
| Abnormal: |
An abnormally long liquefaction time is
present, which may indicate an infection.
|
|
Sperm
count
|
Normal: |
20 million spermatozoa per milliliter (mL) or
more
0 sperm per milliliter if the man has had a
vasectomy
|
| Abnormal: |
A very low sperm count is present, which
may mean
infertility. But a low sperm count does not always
mean that a man cannot father a child. Men with sperm counts below 1 million
have fathered children.
|
|
Sperm shape
(morphology)
|
Normal: |
More than 30% of the sperm have normal
shape.
Kruger criteria: More than 14% of the sperm have a normal shape.
|
| Abnormal: |
Sperm can be abnormal in several ways, such
as having two heads or two tails, a short tail, a tiny head (pinhead), or a
round (rather than oval) head. Abnormal sperm may be unable to move normally or
to penetrate an egg. Some abnormal sperm are usually found in every normal
semen sample. But a high percentage of abnormal sperm may make it more
difficult for a man to father a child.
|
|
Sperm movement
(motility)
|
Normal: |
More than 50% of the sperm show normal
forward movement after 1 hour.
|
| Abnormal: |
Sperm must be able to move forward (or
"swim") through cervical mucus to reach an egg. A high percentage of sperm that
cannot swim properly may impair a man's ability to father a child.
|
|
Semen
pH
|
Normal: |
Semen pH of 7.1–8.0
|
| Abnormal: |
An abnormally high or low semen pH can kill
sperm or affect their ability to move or to penetrate an egg.
|
|
White blood
cells
|
Normal: |
No white blood cells or bacteria are
detected.
|
| Abnormal: |
Bacteria or a large number of white blood
cells are present, which may indicate 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, or diseases that can cause shrinking
(atrophy) of the testicles (such as
mumps).
If a low sperm count or a high
percentage of sperm abnormalities are found, further 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 be needed for further evaluation if the sperm count or motility
is extremely low.
What Affects the Test
Reasons you may not be able to
have the test or why the results may not be helpful include:
- Medicines, such as cimetidine (Tagamet), male
and female hormones (testosterone,
estrogen), sulfasalazine, nitrofurantoin, and some
chemotherapy medicines.
- Caffeine, alcohol, cocaine, marijuana, and
smoking tobacco.
- Herbal medicines, such as St. John's wort and
high doses of echinacea.
- A semen sample that gets cold. The sperm
motility value will be inaccurately low if the semen sample gets
cold.
- Exposure to radiation, some chemicals (such as certain
pesticides or spermicides), and prolonged heat exposure.
- An
incomplete semen sample. This is more common if a sample is collected by
methods other than masturbation.
- Not ejaculating for several days.
This may affect the semen volume.
What To Think About
- A home test kit to determine sperm count has been approved by the U.S. Food and Drug Administration (FDA). This test can help a man find out if he has fertility problems.
- A semen sample collected at home must be
received at the laboratory or clinic within 1 hour. Keep the sample out of
direct sunlight and do not allow it to get cold or hot. If it is a cold day,
carry the semen sample container against your body to keep it as close to body
temperature as possible. Do not refrigerate the semen
sample.
- Consistently detecting sperm in the semen of a man who has
had a vasectomy means that his surgery was not successful, and another form
of
birth control should be used to prevent pregnancy. A
low number of sperm may be present in a semen sample taken right after a
vasectomy. But sperm should not be present in subsequent samples.
- A man whose mother took the medicine
diethylstilbestrol (DES) during her pregnancy with him
has a greater-than-normal risk of being unable to father a child
(infertile).
- More tests may include measuring hormone levels,
such as:
- Other fertility testing,
including sperm penetration, the presence of antisperm antibodies, or analysis
after sexual intercourse (postcoital), may be recommended for infertility
problems. To learn more, see the topic
Infertility Testing.
References
Citations
-
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Other Works Consulted
- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
- Fritz MA, Speroff L (2011). Male infertility. In
Clinical Gynecologic Endocrinology and Infertility, 8th
ed., pp. 1249–1292. Philadelphia: Lippincott Williams and Wilkins.
- Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
Credits
|
By
|
Healthwise Staff |
|
Primary Medical Reviewer
|
Sarah Marshall, MD - Family Medicine |
|
Specialist Medical Reviewer
|
Femi Olatunbosun, MB, FRCSC - Obstetrics and Gynecology |
|
Last Revised
|
December 7, 2011 |