What is Genetic Testing?

Genetic testing can provide useful information by looking for changes in our chromosomes or genes. It can confirm a suspected diagnosis, help patients and families understand what to expect, and impact medical management.


Clinical genetic testing is usually done from a blood sample. Sometimes it involves a blood test from the patient only, and sometimes from family members too. Testing usually requires 1 to 2 tubes of blood per person. In rare cases, other tissue types, like saliva or skin cells, would be needed.

Genetic testing can provide useful information. It can confirm a suspected diagnosis. If a diagnosis is confirmed, it can often help patients and families understand prognosis, or what to expect in the short and long term. It may lead to medical management changes, like whether any medications or therapies should be adjusted.

Genetic testing can lead to an understanding of recurrence risk, or what the likelihood is that the same condition would happen to another family member or to a new baby. Sometimes, positive genetic testing results may trigger a recommendation from your healthcare provider for further evaluation in the patient or their family members.

There are many different types of genetic tests. The type of test recommended by your healthcare provider is based on your or your child’s unique clinical features and family history. Gene sequencing includes single gene sequencing, gene panels, exome sequencing, mitochondrial DNA sequencing and genome sequencing. There are also chromosome-based tests, which include karyotype and chromosomal microarray analysis.

Genetic testing can have various results. They may be positive or negative, or they may need more interpretation in the future as we learn more about genetics.