A genetic test checks the DNA of your cells. It can find changes in your genes, or it can check the number, order, and structure of your chromosomes. Testing may be done on samples of body tissue, blood, or other body fluids such as urine or saliva.
You inherit half of your genetic information from your mother and the other half from your father. Genes determine things such as your blood type, hair color, and eye color, as well as your risk for certain diseases. Testing can find gene or chromosome changes that may cause medical problems.