By Matt C. Bell, MD FACAAI – December 13, 2018
I guess it’s just a sign of the times. Emails went out this morning advertising that one of the country’s largest labs is now offering direct-to-consumer laboratory testing without a doctor’s orders. This has been offered on a smaller scale in the past by other companies, but this is the first time that a company with such a huge national presence has advertised services like this. Presumably this will be a cash pay system as insurers will likely choose not to cover services not ordered by a physician.
Now, on the surface, this may seem like a good thing. Now you don’t have to go to your doctor’s office and pay a copay just to get lab tests ordered. Also, I fully anticipate that physicians (like myself) and physician groups will be cast in the light of “Doctors are just upset because they are losing out on revenue”. I can assure you that that is most certainly not the case. In our “Dr. Google, M.D.” culture, it seems easy for anyone to become an “expert” about nearly any medical condition. While I encourage my patients to be as educated as possible about their health, I caution them to take everything they read online or elsewhere with a grain of salt. Just because someone on social media says that they were cured after using this product or their life was changed after they got the results of this blood test, this is not always applicable to everyone.
The reason that I am personally scared of this new service is the fact that lab tests only tell a part of the story, if they contribute to the story at all. One of the best lessons I learned as a young doctor is that it’s easy for a doctor to order a test, but a good doctor knows how to explain why the test doesn’t need to be ordered. Sometimes we have to order lab tests, but what we as doctors (hopefully) learn in our years of training is: when a lab test needs to be ordered and when it doesn’t and how to interpret normal and “abnormal” results. Results that are labeled as “abnormal” are often not abnormal at all and this can lead to unnecessary consequences for someone not trained to interpret the results.
Anyone who has met me in clinic knows that one of my “soapboxes” is the inappropriate ordering of allergy tests, specifically food allergy tests. I would anticipate that these will be one of the “big sellers” for this lab. Am I against this because I want to monopolize food allergy testing? Of course not! Those who know me know that I am more likely to talk you out of allergy testing than to recommend it. I am EXTREMELY worried about how people, adults and especially kids, are going to choose to interpret these tests. The most likely thing that we will see is people interpreting tests as being “positive” when they are not. A blood test for food allergies is only helpful if three criteria can be met: #1 the symptoms caused are consistent with an immediate hypersensitivity reaction, #2 the symptoms recur with each exposure to that food when consumed at any amount and in any form, and #3 the symptoms occur immediately after eating the food (within 2 hours technically but that is really pushing it). So if you get a headache the morning after you drink milk but not when you eat ice cream, you have failed all three criteria. If that scenario is you and you go to the lab and order a milk allergy test and the results are “positive” for milk allergy, guess what? You don’t have milk allergy! We need to keep in mind that the gold standard for food allergy diagnosis is still the oral food challenge. All other tests are trumped by this test. So if you can eat a food without developing immediate hypersensitivity symptoms – all other test results can be thrown away, regardless of how “positive” they are. We as allergists use blood allergy tests in patients with confirmed food allergies to determine when they are safe to challenge. We never use them to diagnose food allergies. The less likely, but more dangerous, scenario is the rare false negative blood test. On very, very rare occasions, we have patients with definite food allergies that for unclear reasons have a negative food allergy blood test. These patients could theoretically order their own labs, assume a food is safe to eat because of a “negative” test, and then have potentially life threatening consequences.
The bottom line is that we as physicians all assumed this day would eventually come. And I fully understand that a couple of paragraphs from your friendly neighborhood allergist is probably not going to convince everyone not to order those labs they have always wondered about. I would just implore everyone who reads this to stop and answer these 3 questions that I ask myself before I order any lab test (I call them the AID questions, as they AID me in making proper choices when ordering lab tests):
- Actionable: Is the result going to be actionable? (IE am I going to be able to make a meaningful change based on the results of the test)
- Interpret: Based on my knowledge of this test and what it measures, can I make an expert decision on how to interpret it?
- Directly Answer: Based on expert knowledge of the test, does it directly answer the question for which I am looking for an answer?
If the answer to any of those questions is “No”, then doesn’t it make sense to seek the advice of an expert before ordering the test? This applies to both direct-to-consumer testing AND testing done by primary care physicians. If your doctor is ordering tests, ask her/him these questions about the tests being ordered! I can only speak for my practice as an allergy/immunology specialist, but I spend an hour plus everyday untangling messes created by providers ordering tests without a great knowledge of how to interpret the results. I anticipate this only getting worse with direct-to-consumer testing. Trust me, you are not helping us out or making things easier by bringing in your own test results! We are going to do what we are trained to do, get a history, do a physical exam, and then decide what, if any, testing is appropriate. So if you have a concern about your health, see your doctor and if needed, see a specialist. It may not be the easiest or most convenient thing to do, but as I said before, it’s often the right thing to do.