Genetic or DNA testing has developed enough so that doctors can often pinpoint missing or defective genes. The type of genetic test needed to make a specific diagnosis depends on the particular illness that a doctor suspects. Many different types of body fluids and tissues can be used in genetic testing. For deoxyribonucleic acid (DNA) screening, only a very tiny bit of blood, skin, bone, or other tissue is needed.
Genetic testing has potential benefits whether the results are positive or negative for a gene mutation. Test results can provide a sense of relief from uncertainty and help people make informed decisions about managing their health care. For example, a negative result can eliminate the need for unnecessary checkups and screening tests in some cases. A positive result can direct a person toward available prevention, monitoring, and treatment options. Some test results can also help people make decisions about having children. Newborn screening can identify genetic disorders early in life so treatment can be started as early as possible.
If you test positive for a genetic condition, you can better understand how this condition arose in you and your relatives. If you do not yet have symptoms, you can start to plan for the future, such as planning for a family, career, and retirement. You might want to start seeing specialists to help manage the condition. Preventive actions may be useful as well. Drugs, diet and lifestyle changes may help prevent the disease improve treatment. Close relatives might value having this information. They can go through testing themselves to determine their disease risks and the best treatment approach. If you test negative for a genetic risk factor that is known to run in your family you may be relieved that a major risk factor has been excluded.
Read the full writeup here: http://ghr.nlm.nih.gov/handbook/testing?show=all