While all aspects of the medical field are constantly evolving, this is particularly true of genetic testing. Currently, genetic tests are available and recommended for a limited number of medical conditions, though more tests become available each year.
If you are an adult who was born with a heart defect (congenital heart disease) and you are interested in having children, genetic testing can help assess the risk of your child inheriting that condition. It can also indicate the presence of certain genetic syndromes that may have effects beyond your cardiovascular system. Genetic tests are not available for all forms of congenital heart disease. Your cardiologist can help you determine if you are a good candidate.
How Does Genetic Testing Work?
A blood sample is sent to a lab where a scientist analyzes the DNA in the blood, which contains your genetic information. Your genetic information is carried on groups of DNA, called chromosomes. It might help to think of your chromosomes as the books that make up your genetic encyclopedia. Each book contains chapters, sentences and letters that together make up your entire genetic code.
There are various types of genetic tests, ranging from those that look for large changes in the chromosomes themselves (karyotype) down to individual small changes in the letters that make up the individual genes. The scientist looks for information patterns in and around the genes called “markers” or “mutations.” These markers can identify specific gene defects that may be associated with known cardiovascular problems. Identification of these markers may help to screen additional family members who may be affected but have not had symptoms yet. The presence of a gene marker that is associated with a disease only indicates that the person being tested may be predisposed to have that disease. It does not necessarily mean that the person will develop the disease.
If you choose to pursue genetic testing, it is important to do so through a validated laboratory in the context of trained genetic counseling and experienced physicians who can explain the results. While more genetic testing is being covered by insurance, there are still many genetic tests that are not. A genetic counselor can help clarify these issues for you.
How Is Genetic Testing Performed?
Before you have blood drawn and sent to a lab for analysis, you will meet with a counselor or other medical professional who specializes in genetic testing. During this meeting, you will review your personal and family health histories. This meeting will help determine if, based on the condition you are seeking information about, you are a good candidate for a genetic test. You will also be advised of any limitations of the test.
The actual genetic test is like any other blood test. Having blood drawn typically only takes a few minutes. You will be asked to roll up your shirt sleeve (if necessary), and the medical professional who will be drawing the blood will swab the area where the needle will be inserted with an alcohol wipe. A rubber tube may be tied around the upper part of your arm, or you may be asked to make a fist, to make the veins stand out more and easier to access.
A needle attached to a small test tube will be inserted into your vein, and blood will begin to flow into the tube. When a sample that is appropriate for the test has been gathered, the needle will be removed, and you may be asked to press on a piece of gauze placed over the insertion site. This pressure will help stop any bleeding from the tiny puncture site. A bandage will then be placed over the site where the needle was inserted.
Your blood sample will then be sent to lab technicians for analysis. You will receive information when you have the blood test as to when you can expect results. While some genetic tests may be available in a couple of weeks, others may take up to several months to get back.
Is Genetic Testing Safe?
Having blood drawn by a qualified medical professional is very safe. You may experience some momentary pain, similar to getting a shot, when the needle is inserted, and you have some bruising where the needed was inserted after the test is complete. If you have an allergy to latex or to any adhesives, let the person know who is drawing the blood, so he or she can make any necessary adjustments.
Who Will Know the Results?
The results of your genetic testing are considered personal medical information. They cannot be shared with anyone without your permission.
Questions to Ask Your Doctor About Genetic Tests
The following questions may help you talk to your physician about a genetic test. Print out or write down these questions and take them with you to your appointment. Taking notes can help you remember your physician’s response when you get home.
- How accurate is the test?
- Can you refer me to a genetic counselor?
- Is the test covered by insurance?
- Should my other family members be tested as well?