An article in Austin Gastroenterology recently asks this question. It also confirmed what we already know, that genetic testing is now available to the average person and in fact, can now be found in many households across the US.
Thanks to the increase in testing kits now readily available, many people know at least one person who has ordered a DNA test from an out-of-area testing lab.
For example, kits are available from a company such as 23andMe that conducts a saliva-based DNA test. For $200 the consumer receives health and ancestry results.
The companies advertise that they can detect genetic markers (a gene used to study inheritance). They also claim to be able to identify over 200 medical conditions with one test.
That sounds impressive. But are these tests reliable?
Analyzing the Analysis
Dr. Harry Thomas, a Texas gastroenterologist, advises consumers to be cautious. He uses celiac disease as an example. Dr. Thomas explains that it is a common autoimmune disease caused in part by consumption of rye, wheat, or barley, resulting in inflammation that eventually affects the small intestine.
Dr. Thomas explains that about thirty percent of the population in the United States carry the genes that are commonly tested for celiac disease yet they may not be affected by it.
This is evidence that screening for celiac may not be accurate and it presents the possibility of other factors involved in its development.
Celiac, Dr. Thomas notes, is a very complex disease. He explains that some of the factors involved may be viral infections or even the various microorganisms that live in the human digestive tract.
The Emotional Impact of Receiving Test Results
Without the presence of a physician to interpret the test results, the recipient is left to wade through page upon page of information about their prognosis for future diseases or diseases that may be dormant. For anyone unable to grasp the meaning of such reports, the experience can be either overwhelming or have no practical value.
Inaccuracies must also be taken into consideration. First, there is always the possibility of human error. But then consider that the test samples are taken at home and subsequently mailed to a lab. Either of these issues could cause changes in the sample and distort the results.
A nurse practitioner working for Dr. Thomas’ group took one of the mail-in tests. The results showed possible cancer. It was only after seeing a local doctor and being carefully retested that she was given the “all clear”.
I Received the Results From My 23and Me, What Now?
Dr. Thomas recommends that recipients review the test results with a board-certified physician simply as a guide rather than using it as evidence of a medical condition. The physician will evaluate the risks and let the patient know if there is a need for further screening.
Referring back to celiac disease, his recommendation is to see a gastroenterologist, not a genetic counselor. Only a “gut specialist”, he says, has the expertise to analyze the DNA results, check to see if further diagnostic tests are required, and if so, advance to the next level.
Tests to Detect GI Disease
Several gastrointestinal (GI) related illnesses include celiac disease, Crohn’s disease, and ulcerative colitis. A decision to test for damage to the small intestine by way of an endoscopy exam and tissue biopsy should be based on the severity of GI symptoms.
Often a blood test can accurately detect celiac disease and most patients can manage the disease through proper diet.
It is highly recommended that patients with GI disease continue periodic visits to their physician.
Colonoscopies for Colon Cancer
The U.S. Preventive Services Task Force advocates screening for adults 50 to 70 years old for colon cancer. Of course, people with a family history of colon cancer must make periodic screening a priority. Screening for adults over 75 should be decided on an individual basis.
Colon cancer is deemed to be preventable. According to most physicians, colonoscopy exams have been extremely effective in diagnosing early signs of colon cancer. Austin Gastroenterology is waging a campaign to get the word out, especially during Colon Cancer Awareness Month.
A doctor is best positioned to offer advice about lifestyle or other situations that can guard against disease. A medical professional is highly recommended to provide personalized care.