Diving into your DNA: 6 things to know about genetic testing

Everywhere you turn lately, you hear about genetic testing. “We are living in a genomic age. You see DNA testing on TV shows like CSI, in the news and in ads for testing companies,” says Joanne Armstrong, MD, an Aetna senior medical director and lead for genetic programs.

While DNA testing is in vogue, the technology behind it can be hard to understand, especially when it comes to medical testing. “Genetic screening is more complicated than some portrayals let on, and it requires skill to use it effectively,” Dr. Armstrong says. That means direct-to-consumer tests, the ones you can get without a doctor’s order, often fall short.

If you’re interested in having your DNA tested to gain insights about your health, read these six important tips first. They can save you time and money by steering you toward high-quality tests. More important, they can help you avoid drawing the wrong conclusions from your results.

1.   Talk with your doctor first. 

Direct-to-consumer genetic tests, like those from 23andMe and Ancestry.com, can offer fascinating insights about your ethnic heritage. But if you're considering DNA testing for health reasons, it’s important to get your primary care doctor involved.

Experts usually recommend genetic testing only when a patient has a specific medical reason, such as a family history of certain cancers. That’s because no single test can search your DNA for general health risks. And the one-size-fits-all health tests that are bundled with ancestry information are typically not personalized enough to inform medical decisions. Your doctor can tell you if your background and concerns make genetic testing a good idea.

2.   Consult a genetic counselor. 

Although some doctors may be well-versed in genetic testing, many rely on professionals who specialize in the field: genetic counselors. There are over 50,000 DNA tests available now,  measuring thousands of different health risks. These experts can point you to the test that is best tailored to your needs.

Mary Katherine Backstrom of Orlando, Florida, met with a genetic counselor after she was diagnosed with invasive breast cancer in her early 30s. The counselor discussed testing for the BRCA gene mutation. Women who are carriers of the mutation are at higher risk of certain types of cancer, including breast and ovarian. For women like Mary Katherine who already have a diagnosis, a positive BRCA test can indicate whether they should pursue more aggressive treatment and screening for other types of cancer.

Mary Katherine says the visit was empowering: “I didn’t take much college anatomy or biology, so having a trained professional explain how the risks worked out statistically was oddly comforting. After talking it over with my genetic counselor, I felt confident in my decision to get tested.”

3.   Learn about your family health history. 

Heather Shappell is a board-certified genetic counselor who manages Aetna’s Precision Medicine program, which promotes the personalization of health care through DNA testing. “It’s really important that you reach out to relatives to learn as much as you can about their health history,” she says. “The more accurate you can be in reporting your personal and family health history, the more accurate the recommendations of the genetic counselor can be.” Some conditions that run in families, for example, can result from shared environmental factors ― like diet, occupation or climate ― and not genetic tendency. So, even if there’s no screening that will put your particular worries to rest, a genetic counselor may still be able to assess your risk based on your family history alone.

Mary Katherine says that during her hour-long meeting with a genetic counselor, she answered questions about the ages of various family members or the age they died, as well as whether any had cancer. “We talked about cousins, aunts, uncles, maternal and paternal grandparents,” she says. “Because I had three women in my family with breast cancer, plus I was diagnosed at such an early age, that indicated that I should consider the BRCA test.”

Even if you don’t know your all the details of your family history, you can still speak with a genetic counselor about inherited health concerns. 

4.   Some genetic tests are better than others. 

Shappell says about 10 new genetic tests enter the market each day. It’s up to genetics experts to determine which tests offer the most reliable and useful results. Tests that don’t meet quality standards typically won’t be covered by health plans. “One of the most important jobs a health plan can perform is to make sure our members have access to the tests that have a clinical benefit,” Shappell says. “There are tests that might be available ― and even marketed pretty extensively ― that really don’t have any proven value.” Aetna covers thousands of genetic tests for its members.

5.   Some genetic labs are also more reliable. 

Medical DNA tests targeting specific conditions are often much different than those offered by companies that sell directly to consumers. Let’s say you take a direct-to-consumer test and it happens to reveal information that may be medically important, such as a BRCA mutation. Shappell says you’ll want to consult a doctor or genetic counselor. Your doctor will likely need to order additional tests and have those results verified by a high-quality clinical laboratory. “The results you get from a clinical-grade lab can be used to direct medical management and to make better decisions for your health,” Shappell says.

Even among medical labs, quality can vary. “The quality of the result interpretation is so different from one lab to the next, that patients need a genetics expert to guide them to the best option,” Shappell says. She adds that Aetna is focused on ensuring lab quality within its network: “We have a laboratory network team that makes sure we offer members access to labs that perform at the highest levels.”

6.  Got your test results? How to understand your next steps. 

After a lab has returned your test results, your doctor or genetic counselor can explain what the results mean. This information can shape what treatment you receive and how you make health decisions in the future. In Mary Katherine’s case, she tested negative for the BRCA mutation, meaning she could more confidently pursue a less aggressive breast cancer treatment — radiation — instead of having a mastectomy.

The negative result also has implications for Mary Katherine’s daughter, Holland. That’s because BRCA is an inherited trait. “Since I don’t have the gene mutation, she won’t inherit it from me,” Mary Katherine explains. Even so, a strong family history may motivate some individuals to pursue early screening. 

Because new discoveries are made every day, families like Mary Katherine’s should stay in touch with their genetic counselors. Additional testing options may become available to them in the future.

“There's been explosive growth in DNA testing in the last several years, and it shows no signs of slowing down,” Shappell says. “The best advice I can give is, you don’t have to do it alone. Get your doctor or a genetic counselor involved. That way you can have confidence in whatever decisions you make.”