Genetic tests are used to identify changes in people’s chromosomes or genes that can cause genetic conditions. Most genetic testing takes place using a sample of blood so that DNA can be examined. There are four main types of genetic tests that can be performed:
- Diagnostic genetic testing can be used to confirm a diagnosis in a patient who has particular signs and symptoms of a genetic condition.
- Predictive genetic testing can be used to identify individuals who are at increased risk to develop a particular condition before the symptoms appear.
- Carrier testing can be used to identify individuals who are carriers of autosomal recessive genetic conditions. Carriers of these types of conditions will not have any signs and symptoms of the condition but are at risk to have children affected with the condition if both parents are carriers of the same genetic condition.
- Prenatal genetic testing can be used to test for a particular condition during a pregnancy. Samples for this type of genetic testing are retrieved using either chorionic villus sampling (taking a tiny sample of tissue from the placenta) or amniocentesis (taking a sample of amniotic fluid from the womb).
A genetic counsellor can help individuals and families understand which type of testing they require, facilitate the testing with an accredited laboratory and also explain the testing outcomes.