Semen Analysis

What is a Semen Analysis?

This is an analysis of semen produced following ejaculation, which aims to determine the health of the sperm and the fertility potential of the man.

A basic Semen Analysis is required by fertility clinics prior to commencement of fertility treatments e.g. IUI (Intrauterine insemination), IVF (In vitro fertilization). It is recommended to all couples trying to conceive.

Fertility problems can be:

  • 1/3 of the time, due to female factors
  • 1/3 of the time, due to male factors
  • 1/3 of the time, due to a combination of both male & female factors or unexplained

It’s important to determine in the early stages of investigation, whether the difficulty trying to conceive, may be due to a male factor.

A Semen Analysis involves testing:
  • Semen Volume
  • Semen Viscosity
  • Semen pH
  • ‘Other cells’ count
  • Aggregation
  • Agglutination
  • Sperm Count/Concentration
  • Sperm Motility
  • Sperm Morphology
  • Anti-sperm Antibody binding

The following paragraphs explain in more detail how Semen and Sperm are tested.

Definition of Semen

Semen is composed of different types of fluid, which are ejaculated in a specific sequence, in order to optimize the chance of the sperm reaching the egg.
90% of the semen volume comes from glands attached to ducts, through which sperm must pass, to be ejaculated. These fluids come mainly from the prostate gland and seminal vesicles, but smaller amounts also come from the bulbourethral (Cowper’s) glands and epididymides.

These fluids will mix when ejaculated into a sample pot for semen analysis. This is not their natural environment. The female cervix is. This is why sperm will not survive as long in a sample pot. Following intercourse the first part of the ejaculate, which contains the most sperm, carried in the fluid fraction from the prostate gland, is deposited near the neck of the womb. The remaining fluid fractions, containing fewer sperm, will pool in the vagina and essentially form a plug.

That is why it is very important when producing a sample for semen analysis that the first part of the ejaculate is collected in the sample pot. This is the sperm rich part.

When a sample is collected in a sample pot it will take time for the separate fluid parts to mix (liquefy and become thinner), and this is why it recommended to wait 30mins, following ejaculation, before performing any tests. During this time the sample can be transported to the laboratory for analysis.

What is the Semen tested for?

The Semen containing the Sperm is tested for volume, pH, ‘other cells’, aggregation and agglutination.

Semen Volume

The volume of the semen is checked first. It viscosity (thickness) and how well the sample has liquefied (mixed and thinned) is also noted. A normal volume for semen will be between 1.5→6.5ml. You could think of 1.5ml as just less than half a teaspoon. Which isn’t a lot.

Some patients in the past have questioned the larger size of the sample pot.
But the larger size of the pot is to ensure capture of that first most important fluid fraction of the ejaculate.


The pH of the semen can only be determined once the sample has liquefied i.e. all the fluids from different glands have mixed together. Fluid from the prostate gland is more acidic than fluid from the seminal vesicles.
A balance is usually reached between pH7.2→8.0.
A more acidic sample might indicate that the basic fluids are not getting through, and there is either a blockage in the sperm ducts or they are absent (CBAVD).

‘Other cells’

It is natural that there will be cells other than sperm cells in the ejaculate.
These ‘Other cells’ will include epithelial cells, round cells (cells of the immune system or immature sperm cells) and detached sperm heads and tails.

Epithelial cells are cells found on body surfaces. This surface could be the surface of the duct through which sperm travel (genitourinary tract) or cells from the surface of your hands skin. That is why it is always important to wash your hands thoroughly before producing a sample for semen analysis.

Cells of the immune system present in the ejaculate can be a sign of infection or inflammation. These cells are usually confined to the blood system but when there is an infection or inflammation then they will cross the blood-testes barrier to fight the disease. This can also happen following vasectomy.
The cells of the immune system will secrete substances, which can damage sperm or cause sperm DNA fragmentation.
If the number of ‘round cells’ exceeds 5million/ml then antibiotics are recommended.
Immature sperm cells present in the ejaculate could indicate a problem with the sperm maturation process.


Aggregation is the term used to describe when nonmoving (immotile) sperm stick together. It can also describe when moving (motile) sperm stick to other things in the semen in a nonspecific manner, i.e. debris or non-sperm cells.


Agglutination describes when moving (motile) sperm stick together. The sperm often appear clustered together, unable to break free. They can stick head to head, tail to tail or a mix of these. Agglutination suggests there might be anti-sperm antibodies present in the semen. This is tested for using the anti-sperm antibody ‘SpermMar’ Test.

What are Sperm tested for?

Sperm contained within the Semen are tested for count, motility, morphology and anti-sperm antibodies.

Sperm Count/Concentration

Sperm count is the total number of sperm in the ejaculate.
It is determined by calculating the concentration of the sperm in millions/ml and multiplying this by the volume of the semen.
A normal ejaculate should have a sperm concentration greater than 15 million/ml.
A normal ejaculate should have a total sperm count greater than 39 million.

Sperm Motility

Sperm motility describes the forward movement or progression of the sperm. It essentially describes the speed at which sperm swim forward.

Motility is graded as:

  1. Progressive motility - Rapid forward progression either in a straight line or large circle
  2. Non-progressive motility - Movement but no progression
  3. Immotility - No movement

A normal ejaculate sample should contain more than 40% motile sperm.

Sperm Morphology

Sperm morphology refers to the appearance of the sperm.
Scientists have characterized the shape or form of sperm that are more likely to survive the swim to the egg and successfully fertilize it.
These normal forms are generally present in low numbers in the ejaculate. Having as low as 4 in every 100 sperm is still considered a normal sample. However the criteria for judging normal forms is very strict.

Note: Sperm forms with slight abnormalities can still fertilize eggs but with a lower probability.
A clinical study demonstrated that IVF fertilization rates were reduced to 7.6% when patient morphology was

Morphological defects are associated with increased levels of DNA Fragmentation, problems with chromosome structure and aneuploidy.

Anti-sperm Antibodies

Anti-sperm antibodies can be present on the surface of sperm cells. Two types of antibodies are tested for: IgA and IgG. The presence of IgA can be more significant. It may indicate a current infection in conjunction with a high ‘other cell’ count.

Anti-sperm antibodies can affect:

  1. Sperm progression in the cervix of the female partner
  2. Sperm fertilization of the egg
  3. Agglutination (sperm binding to other sperm)

When more than 50% of motile sperm test positive for anti-sperm antibodies then a diagnosis of immunological infertility is made.


Please click the following link for instructions on producing a sample for Semen Analysis.
Producing a Semen Sample for Semen Analysis - Procedure

In Summary

  • Register with your fertility clinic
  • Abstain from sex 2→5 days before sample production
  • Wash hands & genitals thoroughly before sample production
  • Do not use latex condoms or other sperm-toxic substances
  • Check the sample pot is labeled correctly with your personal details
  • Once the sample is produced, close the pot lid tightly
  • Keep the pot warm between 20→37degrees (Close to your skin)
  • Fill out the sample production details and patient history questionnaire form
  • Deliver this form and the sample in the biohazard bag, to the laboratory ideally within 1 hour of production
Results and Repeat Testing

Should any of the sperm parameters being tested not meet WHO (World Health Organisation) guideline threshold levels outlined below, then a repeat semen analysis should be considered. Some parameters are more important than others in relation to fertility potential. A ‘Remarks’ section will be included in all semen analysis reports, which will summarize the significance of the test results, and recommend whether another semen analysis is needed.

The quality of semen samples can vary between ejaculates. Results will be affected by factors such as:

  • Period of sexual abstinence
  • Level of stimulation
  • Stress
  • Illness
  • Or whether the semen sample is complete i.e the whole semen sample was captured in the sample pot

One negative result will always have to be confirmed by a second test due to the potential for variance between samples.

Note: Should a patient provide a fertility clinic with either an incomplete sample for testing or compromised sample for testing (e.g. prolonged time interval since sample production, over exposure of sperm to hot/cold, or use of spermatotoxic substances in sample production), then the fertility clinic cannot be held responsible if an accurate test cannot be carried out.

WHO guideline lower reference threshold for semen characteristics
  • Semen volume: 1.5ml
  • Total sperm number: 39 million per ejaculate
  • Sperm concentration: 15 million per ml
  • Total motility: 40%
  • Progressive motility: 32%
  • Sperm morphology: 4% normal forms
  • pH: 7.2
  • MAR test: 50% motile sperm with bound particles

Other Tests available related to Sperm Health

Other tests which check Sperm Health are available to patients but are not performed on a routine basis.

Sperm DNA Fragmentation

Sperm DNA Fragmentation is a relatively new test, and has not yet been adopted as part of standard testing by most fertility experts. Sperm DNA Fragmentation looks at the packaging of DNA in the sperm head. Sperm DNA Fragmentation testing is not straightforward and different methods are available i.e. Comet, TUNEL, DBT-FISH, SCSA, SCD. The most automated way of testing (SCSA) is quite expensive and not performed in Ireland. Fertility Check uses a method developed by specialists in Spain, which can be preformed in-house (SCD).

Read More....

Genetic Testing

Our genes can hold the answer to unexplained infertility. Often mutations at a genetic level will result in defective sperm production. These specific genes can be tested in order to explore genetic reasons behind infertility. Our genes can also tell us if we carry certain recessive traits likely to affect our offspring.

Read More....

Back to Male Fertility Testing →

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