The AZF study, what is it?

Testing for microdeletions of the AZF region of the Y chromosome helps to determine the cause of male infertility. The fact that there are no sperm in the semen (azoospermia) or extremely few sperm (oligozoospermia) may be due to a mutation of the AZF region of the Y chromosome. Further treatment of the couple's infertility will also depend on the outcome of the test.

AZF and fertility 

Examination of the AZF region involves genetic analysis of a region located on the long arm of the Y chromosome. Genes responsible for spermatogenesis, i.e. sperm production, are present there. The absence of one of these genes or its mutation is the cause of impaired spermatogenesis, which manifests itself in reduced sperm counts or a complete absence of sperm.

According to scientific studies, approximately 25% infertile men have microdeletions in the AZF region.               

The AZF region is divided into three sub-regions: AZFa, AZFb, AZFc.

  • In the case of microdeletions in the AZFa subregion, the chances of obtaining spermatozoa during testicular biopsy are low; usually only Sertole cells, which are responsible for functions regulating spermatogenesis and nutrition, are then found,

  • With AZFb microdeletions, the chance of obtaining sperm during a testicular biopsy is low,

  • The best chance of sperm being present at testicular biopsy is when there is an AZFc-type microdeletion - more than half of patients with this genetic defect undergo testicular biopsy successfully.

Sperm obtained by biopsy are used for in vitro fertilisation by ICSI/IMSI techniques or frozen for later use in assisted reproduction. The incidence of AZFa, AZFb and AZFc are respectively: 0.5-4%, 1-5% , 80%. Genetic alterations within the AZF region are passed on to male offspring.

When to perform an AZF test

If the semen test shows extreme oligozoospermia or azoospermia, the result should be consulted with an andrologist, who will recommend an AZF test if a genetic cause for such a semen test result is suspected.

How to prepare for the AZF study?

You do not need to be specially prepared for the AZF genetic test. It does not require fasting or withdrawal from medication.

Where to perform the AZF test?

The AZF test is performed at each Invimed clinic during the opening hours of the collection centre. You do not need to be registered to have an AZF test unless required by the clinic.

The medical information presented should be considered as general guidelines and does not replace the individual judgement of the doctor regarding the medical management of each patient. The doctor, after a thorough examination of the patient's condition, determines the extent and frequency of diagnostic tests and/or therapeutic procedures, taking into account specific medical indications. All medical decisions are made in full consultation with the patient.

Author of the article

Invimed editorial team - we serve patients by solving their fertility problems. We use world medical knowledge, state-of-the-art technology and treatment methods. We are here to make dreams of parenthood come true. The smiles on the faces of happy parents give meaning to our work.

See all articles →