Genetic testing
Genetic tests can be used to:
- confirm or rule out a suspected genetic condition
- assess your chance of developing or passing on a genetic condition.
Types of genetic tests
There are different types of genetic tests.
Screening tests
Screening tests are provided to healthy people and can identify conditions early, before symptoms start, or determine if you are at high risk of a condition. Screening tests are an important part of public health programs. Although they do not provide a definite diagnosis, screening tests can:
- determine if further testing is necessary
- provide people identified at risk of a condition with the opportunity to make lifestyle changes or undertake treatment to reduce disability or death.
An example of a screening test is the newborn screening test, also known as the Guthrie test. This is a blood test for a range of genetic conditions performed soon after birth.
Find out more about the tests you and your baby can have during pregnancy.
Diagnostic tests
A diagnostic test can accurately identify if you have a specific genetic condition and determine a prognosis (the likely outcome of that condition). It is normally used to confirm the results of a screening test. An example of a diagnostic test is amniocentesis, used during pregnancy to diagnose conditions such as Down syndrome.
Find out more about diagnostic tests during pregnancy.
Carrier testing
Carrier testing determines if you carry an altered gene that will not affect your health but may increase your chance of having children with a particular condition, for example cystic fibrosis. This testing is normally offered if you have a family history of certain genetic conditions.
Predictive and presymptomatic testing
These tests are used to identify your risk, as a currently healthy person, of developing a condition later in life. This information gives you the opportunity to take steps to reduce the chance of developing the condition or minimise your symptoms.
Presymptomatic tests are performed before you develop symptoms of a genetic condition and can allow you to make lifestyle changes that will reduce the severity of your symptoms.
A disorder you might have presymptomatic testing for is haemochromatosis, or iron overload. Discovering you have this condition before you develop symptoms can allow you to take preventative measures, such as giving regular blood donations to prevent symptoms such as liver damage.
Presymptomatic testing is normally offered to you if you have a family history of the condition.
Predictive tests can identify gene changes that increase your chance of developing a genetic condition. An example is testing for the BRCA1 and BRCA2 gene variants (altered genes) associated with an increased risk of breast cancer.
Just because you carry this altered gene does not mean you will develop cancer, but you will be considered at greater risk than someone without the altered gene. Knowing about your increased risk allows you to undertake measures to reduce your risk, such as regular medical check-ups or surgery.
Forensic testing
Forensic tests use biological material, such as saliva or blood, to identify you for legal reasons. This can include to determine paternity (whether a man is the father of a certain child) or identify a criminal suspect. They are not used to detect gene changes.
More information
Remember
- Genetic testing can:
- assess your chance of developing or passing on a genetic condition
- confirm or rule out a suspected genetic condition.
Acknowledgements
Office of Population Health Genomics
This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.