Should we use mail-order test kits to diagnose ourselves?

Like you, doctors are trying to figure that out, too, as the market for mail-order testing expands.

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“Would it help to send off her spit?” the father of one of my patients asked me earlier this year, referring to the DNA tests that are becoming widely used for ancestry and other purposes. His daughter suffers seizures, and he wondered if the cause might be genetic. I told him no — she didn’t have the symptoms of genetically based seizure disorders, and if she did, our hospital has tests it would run.

I’m noticing more parents asking whether their kids should have “at-home” testing for everything from genetic conditions to thyroid disease. Doctors also talk about these tests amongst themselves, mostly to try to sort out confusion about just how to advise patients. We aren’t sure of our responsibilities when patients come to us with a self-diagnosis in hand, based on a kit they’ve ordered online. Should we accept tests that aren’t from hospital-affiliated labs? Order our own lab work? What if the patient has no symptoms?

There are more of these self-tests than I can keep track of, but of the ones I know, at least some are not scientifically valid; flipping a coin may be more accurate. There are food “sensitivity” tests that do not test for IgE, the antibody typically used to identify allergens. Also, direct-to-consumer companies increasingly request blood through a capillary sample — obtained by pricking your finger. Hospitals usually use such samples in specific instances, notably for diabetes patients, because it is much faster than drawing blood from a vein. But capillary readings have slightly higher glucose readings, overestimating the actual numbers. And it is unclear what effect shipping blood through various climates has on samples.

For parents, most of these tests aren’t kid-friendly, yet. But these questions will keep coming for children and adults alike — DNA is becoming a consumer product, thanks partly to huge growth in genealogy testing, which more than doubled in volume in 2017. Meanwhile, the global market for self-monitoring test kits was nearly $21 billion in 2017, and is growing rapidly.

On a recent work trip overseas, I stopped in at LetsGetChecked, a four-year-old Irish company that last year began selling some of its tests in North America. Out of its many options, I chose two tests, including a thyroid test that isn’t available here. It took four jabs to my fingertips to get enough blood for a sample for both — my fingertips ached for days.

LetsGetChecked’s founder and CEO, Peter Foley, told me that companies like his will improve health care, lowering costs by eliminating needless visits from patients seeking routine tests. It will be more convenient for patients, since they won’t need to interrupt their lives to get tests done. Those are both good things.

But I’ve read the legal disclaimers for several self-testing companies, including LetsGetChecked. All of them tell customers to confirm results with a doctor. Doing so won’t prevent doctor visits, and you’re effectively paying twice for a test. While the companies involved tout their compliance with HIPAA, the law allows for anonymized data to be shared — or sold — and researchers have used such data to identify individuals.

These tests can also make the numbers seem more important than they are, says Dr. David Stukus, who teaches pediatric medicine at Nationwide Children’s Hospital in Ohio. He notes that tests “can only be interpreted with the patient’s detailed medical history.” What’s normal for one patient could be abnormal for another, he says. Which is why doctors order tests for specific conditions, and only when we think we have good reason. Taking lots of tests might be a hypochondriac’s dream — LetsGetChecked says a few clients order almost all of its available tests, which cost between $49 and $299 each — but volumes of random information are usually not helpful for diagnosing conditions.

Self-testing could play a useful role in health care, if we can establish that the tests are valid. Tests should only be used when someone has a good medical reason to do so, such as symptoms or a family member’s diagnosis. They are not motivational tools such as those from Apple, Google, and Fitbit that track personal eating, sleeping, and fitness habits to encourage healthier lifestyles. One possible model comes from InsideTracker, a Cambridge company that uses DNA testing and blood testing for indicators like cholesterol and vitamin D, pairs the data with medical information customers enter themselves, and then creates personalized wellness advice. Its founder and chief scientific officer, Gil Blander, published a peer-reviewed paper last month with colleagues showing the platform may improve cholesterol levels and other health measures.

We’ll need much more than one study to validate its efforts, but InsideTracker partners with or has advisers from major research institutions such as Harvard, MIT, and Tufts. Both parents and doctors need to look for such credentials before using self-tests.

For now, I advise the parents of my patients to leave the testing to the health care system. It’s just not worth fretting over information that may not be accurate. I found it nice to learn that LetsGetChecked didn’t find anything wrong with my thyroid. But it isn’t yet worth the achy fingertips.

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This story has been updated to reflect that the writer took two self-diagnostic tests from LetsGetChecked.