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Genetic testing

Y microdeletion testing

The genetic test for missing Y-chromosome segments - a key investigation in severe male infertility.

Key facts

At a glance

  • Who is tested: men with severely low or absent sperm counts, typically below 5 million per ml, as part of the fertility workup.

  • What it looks for: missing segments (AZFa, AZFb, AZFc) in the Y-chromosome regions that govern sperm production.

  • Why the region matters: AZFc deletions often leave retrievable sperm for ICSI; complete AZFa or AZFb deletions generally do not.

  • The inheritance point: sons conceived via ICSI inherit the deletion - and the fertility implications - which counselling covers.

  • Results: a blood test with results in two to four weeks, interpreted alongside hormones and karyotype.

The full picture

What this test involves, and how to get it

The Y chromosome carries the AZF (azoospermia factor) regions that drive sperm production, and small deletions here are among the commonest genetic causes of severe male infertility - found in a meaningful percentage of men with counts below five million per millilitre or no sperm at all. Testing is a straightforward blood DNA analysis, run alongside karyotyping and hormone tests in the standard workup of severe oligospermia and azoospermia. The deleted region is the meaningful detail: AZFc deletions, the most common, usually still permit sperm retrieval from the testis for ICSI in a majority of cases, while complete AZFa or AZFb deletions predict that surgical retrieval will almost certainly fail - knowledge that spares men an operation with no realistic prospect, and redirects the conversation to donor sperm or other routes sooner and more kindly.

One implication deserves explicit counselling: sperm carrying the deletion pass it to every son, who will inherit the same fertility problem - a foreseeable, discussable fact rather than a reason against treatment, but one couples should weigh knowingly; daughters are unaffected. Y microdeletion testing is part of NHS male fertility assessment through urology and fertility services, with results in two to four weeks; private fertility clinics include it in male factor workups with similar turnaround and typically faster clinic access. Results always belong in context - deletion type, hormone profile and examination together shape whether retrieval is attempted - which is why the report should land in a fertility consultation rather than an inbox.

A quiet reminder

This guide is for information, not medical advice.

Your own clinician knows your history and can tell you which parts apply to you. Next review of this page: 2027-09-27.

Frequently asked

Common questions about Y microdeletion testing.

Quick, plain-English answers to what people ask us most.

  • What is Y microdeletion testing?

    Y microdeletion testing is a genetic test that looks at specific DNA information relevant to a particular condition, inherited risk, or family planning question. It is usually considered when there is a personal or family history that makes this information clinically relevant. Genetic counselling is often recommended alongside testing to help you understand what a result would mean.

  • Why would someone need this test?

    This type of testing is typically used to assess carrier status, inherited risk, or a specific genetic cause for a condition already suspected on clinical grounds. It may be recommended by a GP, specialist, or fertility clinic depending on the context. The decision to test is usually made together with a healthcare professional, given the personal implications involved.

  • Do I need to prepare for this test?

    Most genetic tests only require a simple blood sample or saliva swab, with no special preparation such as fasting needed. What matters more is having a pre-test conversation, often with a genetic counsellor, about what the possible results could mean for you and your family. This helps you make an informed decision before proceeding.

  • What happens during the test?

    A blood sample or saliva swab is taken and sent to a specialist genetics laboratory for analysis. This part of the process is quick and generally painless. The laboratory work itself, including sequencing and interpretation, is what takes the most time.

  • How long do results take?

    Genetic test results generally take longer than routine blood tests, often several weeks, because of the specialised laboratory analysis and interpretation involved. Your clinician or genetic counsellor will give you a realistic timeframe when the test is arranged. Results are usually discussed with you in a dedicated follow-up appointment rather than by letter alone.

  • What do the results mean, and what happens next?

    Results are usually explained by a geneticist or genetic counsellor, who can put the finding into context and discuss any implications for you and, where relevant, your family members. Next steps vary widely depending on the specific result and may include further testing, specialist referral, or reproductive planning advice. It is normal to need time and support to process this kind of information.

  • Is genetic testing available privately, and how much does it cost?

    Yes, many genetic tests can be arranged privately, often with shorter waits than some NHS genetics pathways depending on the specific test and local services. Cost varies by provider and confirmed before booking. Private genetic counselling is usually included or available alongside testing to support you in understanding the result.

  • Is this type of test accurate?

    Modern genetic testing carried out in accredited laboratories is highly accurate for detecting the specific changes it is designed to look for. However, genetics is complex, and a result is not always straightforward to interpret in isolation - context from a genetic counsellor or specialist is important. Very rarely, further confirmatory testing may be recommended.

  • How do I book this test privately?

    You can usually arrange this through a private genetics clinic or fertility service, either with a referral or via self-referral depending on the provider. Pre-test counselling is typically arranged as part of the process.