Testing is used to diagnose or determine the likelihood of, genetic-related health problems. For example, a pregnant woman may undergo a prenatal test to determine if her unborn child will likely develop a disorder. People usually have a genetic consultation to provide support and information, which sometimes includes guidance on testing.
Gene, Chromosomal and Biochemical Tests
Genetic testing usually requires a blood or tissue sample. It is split into three groups:
- Gene tests. These tests look at DNA for potential problems, such as missing or overly active genes.
- Chromosomal tests. These tests look for problems with the number and structures of chromosomes.
- Biochemical tests. These tests look at the actions of certain proteins, which in turn can detect problems with genes.
Types of Genetic Testing Available
- Diagnostic – these tests are carried out when there is a reason to believe someone already has (or is at risk to) a health problem.
- Predictive and pre-symptomatic – these tests determine whether or not someone is at increased risk of developing a health problem.
- Carrier – these tests show if a person is carrying genes for a health problem that, while not affecting themselves, could be passed on to their offspring.
- Pre-implantation – these tests are carried out on embryos to check for potential fetal problems.
- Prenatal – these tests are carried out on some pregnant women to determine genetic-health issues in a fetus.
- Newborn – these tests are carried out on newborn babies to determine any genetic health issues.
- Pharmacogenetic – these tests determine the influences on drug interventions on the genomes of individuals.
- Research – where testing is used to forward research in the field of genetics.
Genetic testing is not always health-related, for example, DNA testing is used in exploring ancestry. Sometimes genetic testing is carried out direct-to-consumer, where the individual takes a sample themselves and sends it back to the service, usually without intervention from a healthcare worker.