A semen analysis is a test of male fertility controlling the quantity and quality of the sperm of your partner.
The first factor to examine is the number of sperm in the sample, i.e. the concentration of sperm per millilitre of semen. A low number of sperm is the cause of infertility in the 25-30% of all cases.
If the number of sperm per millilitre of the ejaculation is more than 20 million, the sample is Normozoospermic. If it is less than 20 million per millilitre of ejaculation it is considered Oligozoospermic.
There are cases in which there is no sperm in the ejaculation, which represents 3-4% of all cases of infertility, and then the patient is Aspermic.
It may happen that in some patients sperm are ejaculated only sometimes and very sparingly, so called Criptozoospermia.
The motility or sperm mobility will be also evaluated. It is important that sperm has a forward motion, fast and progressive.
There are four types:
- Fast progressive spermatozoa (normal value > 25%)
- Slow progressive spermatozoa (normal value > 50%)
- Non progressive spermatozoa
- Immobile sperm
When the sperm’s mobility is reduced the medical term used is Asthenozoospermia.
The presence of antisperm antibodies will be analysed. This can be easily carried out using a microscope since the sperm, in this case, clump or stick by heads or tails and thus cannot progress.
Subsequently this condition has to be confirmed with a specific analytical test.
In addition, it is necessary to analyze sperm vitality, i.e., the number of sperm that are alive. We know that mobile sperm are alive, but non-mobile sperm may be alive or dead. If the percentage of spermatozoa alive is less than 60% there is a Necrozoospermia condition.
Finally, it is important the nuclear maturation that allow us to see the type of nuclear proteins, histones and protamines. It is known that the body’s cells contain histones but mature sperm is the only cell where histones are replaced by protamines, which contributes to having more nuclear chromatin compaction. If the percentage of mature sperm is equal or higher than the 74%, the sample is normal.