Measuring the quality of sperm

On average it takes one year for a couple to conceive. Should your attempts remain unsuccessful for longer than this, consulting a health professional will enable you to carry out a more in-depth diagnosis of the situation. You should be aware that the causes of subfertility of a couple are :

These figures demonstrate that it is necessary to carry out examinations both on the woman and the man's sides.

1. Basic examinations

Semen analysis

The semen analysis is generally the first examination to be carried out on the man. This examination measures several parameters which characterise the sperm's fertilising ability: volume, viscosity, amount of spermatozoa per millilitre, motility of the spermatozoa, size and shape of the spermatozoa, doses of certain substances (zinc, fructose, carnitine, etc.).

The further the results of this examination diverge from the norm, the lower the fertility of the sperm is. The normal values for fertile sperm are summarised in the table below :


Greater than or equal to 2.0 ml

PH Between 7.2 and 8.0
Sperm concentration Greater than or equal to 20 million per millilitre
Total number of spermatozoa Greater than or equal to 40 million
Motility (1 hour after ejaculation) Greater than or equal to 50% motility
Motility (3 hours after ejaculation) Greater than or equal to 30% motility
Morphology Greater than or equal to 50% of normal morphology
Vitality Greater than or equal to 75% of living spermatozoa
White blood cells Less than 106/ml
Zinc 4-14 µmole/ejaculation
Fructose 25-103.9 µmole/ejaculation
Carnitine 0.8-2.85 µmole/ejaculation

A semen analysis allows one to diagnose several problems in the fertilising capacity of the sperm. Among these are :

DNA fragmentation test

This recently developed technique is less well-known and prescribed less often than the semen analysis. The DNA fragmentation test is nevertheless a decisive test that is complementary to the semen analysis. This test measures the state of the DNA of the spermatozoa. The head of the spermatozoon contains DNA, i.e. the individual's genetic material. Fragmentation signifies that some strands of DNA have been broken. If these breakages are not serious, then they will be repaired in the oocyte after fertilisation. However, above a certain level of breakages, this repair process is not possible at a sufficient level to allow the embryo to develop in a normal fashion. This deterioration of the DNA can be due to an excess of free radicals.

Standard values :

All too often, investigations on the man's side are limited to the semen analysis. However, a good semen analysis does not at all imply good DNA fragmentation. These two results are completely independent of each other. It is therefore recommended you ask to have a DNA fragmentation test as well as a semen analysis.

2. Detailed examinations

Depending on the results of these first tests, if necessary further examinations can be carried out. Some examples are :