Genetic testing – sometimes called genomic testing – finds changes in genes that can cause health problems. It's mainly used to diagnose rare and inherited health conditions and some cancers.

Why would I be offered a genetic test?

You may be offered a genetic test because:

• your doctor thinks you might have a health condition caused by a change to 1 or more of your genes
• someone in your family has a health condition that's caused by changes to genes
• some of your close relatives have had a particular type of cancer that could be inherited
• you or your partner have a health condition that could be passed on to your children

If you have any questions, talk to your doctor about having a genetic test.

What a genetic test can tell me

A genetic test can:

• help to diagnose a rare health condition in a child
• help you understand whether an inherited health condition may affect you, your child or another family member, and help you decide whether to have children
• show if you are at higher risk of getting certain health conditions, including some types of cancer
• guide doctors in deciding what medicine or treatment to give you
• guide doctors on whether you're able to join a clinical trial

The NHS is introducing whole genome sequencing through the NHS Genomic Medicine Service.

Whole genome sequencing looks at all your genetic material at the same time (not just part of it, as with other types of genetic test).

You need to be referred for genetic testing by a doctor.

Talk to your hospital specialist about whether testing is right for you.

Is genetic testing free on the NHS?

Genetic testing is free on the NHS if you are referred for it by a hospital specialist.

You will generally only be referred if you have a suspected genetic health condition or if you have a particular type of cancer.

Genetic counselling

If you're offered a genetic test, you may be referred to a genetic counsellor to help you think through what the test means for you and your family.

A genetic counsellor can help you understand:

• the risks and benefits of you having a genetic test
• the potential results of your test and what they mean
• how your family members may be affected if the test shows a serious health condition runs in your family
• the risk of you and your partner passing on a health condition to your children
• your options if you have a child with an inherited health condition and you do not want your next child to inherit it

A genetic counsellor can also direct you to relevant patient support groups.

The British Society for Genetic Medicine has a list of organisations that offer information and support.

The charity Genetic Alliance UK has more information about making the decision to have predictive testing.

If you decide not to have a genetic test, you will still receive care and support from healthcare professionals.

The impact on your family

You may want to consider how the results of a genetic test may affect you and others in your family.

If the genetic test shows there are changes to your genes that cause a health condition, this may mean that other members of your family also have it. In this situation, your doctor may recommend that other members of your family also have a genetic test.

There's also a chance that the test gives you information about your relatives that you or they may not have known before. For example, it may show that you were adopted or that your biological father is not who you thought they were.

This is because the test can show that you do not share genes with your family members.

Find out more information from Genetic Alliance UK about the risks and benefits of genetic testing.

Having a genetic test

A genetic test is usually done using a sample of your blood or saliva.

If you've been referred for a genetic test because you have cancer, the test will be done on a sample of the tumour that has already been removed as part of your treatment.

The sample of blood, saliva or body tissue is sent to a genetic testing laboratory to be analysed.

Getting the results

You'll be told when to expect the results of your test. Depending on the reason for your test, it could be weeks or months. You may need further tests.

The results from the test may show:

• you have a change in your genes which is known to cause a health condition
• you do not have a change in your genes which is known to cause a health condition
• it's not clear what the results mean for your health (but doctors may have a better understanding of the results in the future)

After you get your results, you may be referred to a genetic counsellor to help you understand what they mean for you and your family.

Will it affect my insurance?

When applying for some types of insurance policies, an insurance company may ask you to provide medical information about you and your family.

You will have to disclose a health condition that has been diagnosed by genetic testing, but you will not usually have to disclose the results of predictive genetic testing – that is testing to show if you're more likely than other people to get a certain health condition in the future.

The information that you need to share with an insurance company is regulated by a voluntary government code agreed with the Association of British Insurers called the Code on Genetic Testing and Insurance.

The NHS will not give your genetic test results to an insurance company without your consent.

How your data will be used

Your genetic data includes your sample (blood, tissue or saliva), clinical information about your health condition and the results of your test.

This data may be used in:

• your individual care
• planning to improve the health services you and others receive
• research

The data from your genetic test is stored locally. Data from whole genome sequencing is stored in a secure national database. Where necessary, information that can identify you, such as your name and address, is removed. Your data can only be accessed by approved staff.

If you have a genetic test (including whole genome sequencing) on the NHS, it's not possible to stop your data being stored and shared. If you have already opted out of data from your health records being shared, this does not apply to your genetic test data.

Find out more from NHS England about what data about you has been stored and how it is used.

The NHS is responsible for your genetic data. Find out more from NHS England about the NHS's responsibility as a data controller.

Find out more about how the NHS manages your data in the NHS England Privacy Notice.