SEMEN ANALYSIS

WHAT IS DIAGNOSTIC SEMEN ANALYSIS (DSA)?

This is a test undertaken where a laboratory scientist (biomedical or clinical) will analyse semen. The results obtained from this will provide an indication of whether there is anything that needs to be investigated further. It will help the clinical staff determine if there is an obvious issue with sperm quality/function.

The test will involve a man producing their sample through masturbation into a container provided to them by the laboratory. If a patient cannot masturbate or struggles with this, then a non-toxic condom was maybe given to them to enable sexual intercourse to take place. The containers and condoms must be checked by the laboratory to ensure that they do not kill sperm.

WHAT IS LOOKED AT IN THE LABORATORY?

There are generally two parts of a semen analysis:

Macroscopic analysis - this is where the semen is looked at for volume, pH, viscosity and liquefaction. The colour may be reviewed but this generally only occurs if the sample looks different from what is expected.
Microscopic analysis - this is the part of the test where samples are prepared and looked at under a microscope. This will look at motility, concentration, morphology, vitality and round cells.

These parameters will be discussed on this page so that the terms can be understood.

Once the sample is analysed, results are checked and reported along with any values that may not meet the normal range. Some laboratories will also make additional comments so that the doctor can undertake further tests or to enable them to interpret the results better.

WHAT ARE THE MACROSCOPIC CHECKS?

WHAT ARE THE MICROSCOPIC CHECKS?

WHAT TECHNIQUES ARE USED TO ANALYSE SAMPLES?

This will depend on the laboratory. Some will use automated machines for microscopic analysis, whilst others use manual techniques with scientists undertaking examinations/calculations. There is no right or wrong way. You should be confident in the laboratories results though and possibly look for a mark of quality. This may be in the form of accreditation to a standard. In laboratories for diagnostic testing, this should be ISO15189 or equivalent.

Volume is measured by weight using a balance. The collection container is weighed before sample collection and after.

Viscosity is usually measured using a plastic pipette, where semen is drawn up and then expelled. The length of the semen as it leaves the pipette will indicate how thick the sample is.

Colour and liquefaction are undertaken by visual appearance.

pH is measured either using special strips called indicator papers or by using a pH meter.

Microscopic checks are undertaken using special equipment called microscopes, usually with phase-contrast imaging (a special type of viewing on non-stained items).

Concentration is calculated using counting chambers; of which there are many types. The gold standard is the neubauer haemocytometer.

Morphology and round cells are assessed on stained preparations (Papanicolaou, romanowsky, diff-quick etc) and microscopy.

WHAT ARE NORMAL VALUES?

They are a set of values that have been produced by the World Health Organisation (WHO) that can be referenced when reporting results. They act as a guide for HCP's to interpret results and allow management to proceed for a man/couple. The lower reference limit is often used and can be described as the lowest possible value your results can be before they are classed as abnormal. Here are the current lower reference limits for semen analysis:

when may I neeD TO HAVE MORE THAN ONE TEST?

Semen analysis may give an indication of the quality of your sperm or direct management, but it is not without its limits. Results can differ for the same patient between tests, showing that there are factors that influence sperm/semen production. The following list is a guide only. Any patient that has been asked to produce more than one sample should ask their HCP why.

To confirm the results of the first test, whether this be true 'normal' or to confirm an 'abnormal' result. NICE guidelines suggest that for a parameter that is reduced, 3 months should be left before a repeat is undertaken.
Loss of sample - this may be through the incomplete collection or through the use of a condom. This could impact the sperm numbers/concentration.
There may have no sperm detected in the sample (called azoospermia). In this case, a repeat should be done as soon as possible to confirm this.
If a patient has had a fever-inducing illness in the last three months, they may require a repeat of any of the parameters are reduced.
If there are indications that something may have affected the results - examples include acute illnesses, medication use, recreational drug use.

REFERENCES:

WHO laboratory manual for the examination and processing of human semen (2021) 6TH EDN. 265 Geneva: World Health Organisation. [online]

National Institute for Health and Care Excellence (NICE) 2013. Fertility Problems: Assessment And Treatment CG156. [online]