Semen analysis is a test to measure the amount and quality of a man's semen and sperm. Semen is the thick, white, sperm-containing fluid released during ejaculation.
The test is sometimes called a sperm count.
How the Test is Performed
You will need to provide a semen sample. Your health care provider will explain how to collect a sample.
Sample collection may involve masturbation and collecting the sperm into a sterile container. It may also be collected during intercourse by using a special condom supplied by your health care provider.
A laboratory specialist must look at the sample within 2 hours of the collection.
The earlier the sample is analyzed, the more reliable the results. The laboratory specialist will look at the sample to determine the following details:
Fluid coagulation (thickening into a solid) and liquefaction
Fluid thickness, acidity, and sugar content
Resistance to flow (viscosity)
Sperm movement or motility
Number and structure of the sperm
Volume of semen
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How to Prepare for the Test
Do not have any sexual activity that causes ejaculation for 2 - 3 days before the test.
Examples of parameters measured in a semen analysis are: sperm count, motility, morphology, volume, fructose level and pH.
Approximate pregnancy rate varies with amount of sperm used in an artificial insemination cycle. Values are for intrauterine insemination, with sperm number in
total sperm count
, which may be approximately twice the
total motile sperm count
Sperm count, or
to avoid mixup, measures the concentration of sperm in a man's ejaculate, distinguished from
total sperm count
, which is the sperm count multiplied with volume. Anything over 20 million sperm per milliliter is considered normal. Anything less is considered oligozoospermia . A vasectomy is considered successful if the sample is azoospermic . Some define success with rare non-motile sperm are observed (fewer than 100,000 per millilitre). Others advocate obtaining a second semen analysis to verify the counts are not increasing
(as can happen with re-canalization) and others still may perform a repeat vasectomy for this situation.
The average sperm count today is around 60 million per milliliter in the Western world, having decreased by 1-2% per year from a substantially higher number decades ago. Chips for home use are emerging that can give an accurate estimation of sperm count after three samples taken on different days. Such a chip may measure the concentration of sperm in a semen sample against a control liquid filled with polystyrene beads.
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The motility of the sperm is evaluated. WebMD defines normal motility as 60% of observed sperm, or at least 8 million per millilitre, showing good forward movement The World Health Organization has a similar value of 50% and this must be measured within 60 minutes of collection.
A more specified measure is
, where the motility of sperm are divided into four different grades:
: Sperm with progressive motility.
These are the strongest and swim fast in a straight line. Sometimes it is also denoted motility
: (non-linear motility): These also move forward but tend to travel in a curved or crooked motion. Sometimes also denoted motility
: These have non-progressive motility because they do not move forward despite the fact that they move their tails.
: These are immotile and fail to move at all.
The morphology of the sperm is also evaluated. With WHO criteria as described in the old manual of 1989, a sample is normal if 30% or more of the observed sperm have normal morphology.
The volume of the sample is measured. WebMD advises that volumes between
1.0 mL and 6.5 mL are normal
WHO criteria specify that any volume greater than
2.0 mL is normal. Low volume may indicate partial or complete blockage of the
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seminal vesicles , or that the man was born without seminal vesicles. In clinical practice, a volume of less than 2 mL in the setting of infertility and absent sperm should prompt an evaluation for obstructive azoospermia . A caveat to this is be sure it has been at least 48 hours since the last ejaculation to time of sample collection.
The level of fructose in the semen is measured. WebMD lists normal as at least
WHO specifies a normal level of 13 μ mol per sample. Absence of fructose may indicate a problem with the seminal vesicles.
The pH of the sample is measured. WebMD lists a normal range of 7.1-8.0; WHO criteria specify normal as 7.2-7.8 Acidic ejaculate (lower pH value) may indicate one or both of the seminal vesicles are blocked. A basic ejaculate (higher pH value) may indicate an infection A pH value outside of the normal range is harmful to sperm.
The liquefaction is the process when the gel formed by proteins from the seminal vesicles is broken up and the semen becomes more liquid. It normally takes less than 20 minutes for the sample to change from a thick gel into a liquid . An abnormally long liquefaction (more than 30 minutes at 37 24°C) time may indicate an infection.
Total motile spermatozoa
Total motile spermatozoa
total motile sperm count
(TMSC) is a combination of sperm count, motility and volume, measuring how many million sperm cells in an entire ejaculate are motile.
A few of the common normal values are listed below.
The normal volume varies from 1.5 to 5.0 milliliter per ejaculation.
The sperm count varies from 20 to 150 million sperm per milliliter.
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At least 60% of the sperm should have a normal shape and show normal forward movement (motility).
However, how to interpret these values and other results from a semen analysis is not completely certain.
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
Abnormal results may suggest a male infertility problem. For example, if the sperm count is very low or very high, there is a likelihood of being less fertile. The acidity of the semen and the presence of white blood cells (suggesting infection) may influence fertility.
However, there are many unknowns in male infertility. The results from the test may fail to explain the cause. If a low sperm count or abnormal semen is found, further testing may be required.
The sample is tested for white blood cells . A high level of white blood cells (over 1 million per milliliter) may indicate an infection.
Aspermia : absence of semen
Azoospermia : absence of sperm
Hypospermia : low semen volume
Oligozoospermia : low sperm count
Asthenozoospermia : poor sperm motility
Teratozoospermia : sperm carry more morphological defects than usual
Volume can be determined by measuring the weight of the sample container, knowing the mass of the empty container. Sperm count and morphology can be calculated by microscopy. Sperm count can also be estimated by kits that measure the amount of a sperm-associated protein, and are suitable for home use.
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Computer Assisted Semen Analysis
(CASA) is a catch-all phrase for automatic or semi-automatic semen analysis techniques. Most systems are based on image analysis , but alternative methods exist such as tracking cell movement on a digitizing tablet Computer-assisted techniques are most-often used for the assessment of sperm concentration and mobility characteristics
- The SQA-V, also known as the 'Sperm Quality Analyzer or Spermalite, is a high performance sperm analysis instrument used to test male fertility. It combines electro-optics, computer algorithms and video microscopy to provide a precise and accurate 75 second automated semen analysis.
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