Today, if you wish, you can go get a staggering amount of granular data about your health without your doctor’s involvement. All on your own, you can get an MRI of your entire body, a CT of your coronary calcium, an ultrasound of your blood vessels, and maybe someday an immersion ultrasound in a spa.
Direct-to-consumer medical imaging tests are a huge and growing business worth billions of dollars. Over 100,000 Americans are already customers. But do these test results actually make us healthier?
As a radiologist, a doctor specialized in the alchemy of turning information into health, I translate data hidden in images into words that motivate behavior to promote healthier, longer lives. Because it is central to what we do, radiologists have grappled for decades with the question of whether and how information improves health. It turns out to be surprisingly complicated.
In order to make a difference in someone’s health, the test must accurately predict or diagnose a condition, resulting in a change in mindset and behavior, and that change in mindset and behavior must produce a better outcome than not doing the test.
For example, whole-body MRI of the general public, a test not recommended by any medical guideline, medical society, or payer, creates information by taking a picture of your body. That information is accurate for some diseases but not others. It might change your mind by finding something you didn’t know about, like a small mass in your kidney or thyroid gland, which then might change what you or your doctor does. For example, your doctor might order another test to better understand if the mass is important or perform surgery to take it out.
This seems logical. But the reason whole-body MRI of the general public isn’t recommended while other screening tests are is because in the absence of evidence, it is believed to be unlikely to produce a better outcome than doing nothing at all.
Many people think, as I once did, that early diagnosis always improves health. That logic is especially intuitive for an early diagnosis of cancer. But in many cases, that intuition, however understandable, can be wrong. Finding something with a diagnostic test might not help, despite creating an illusion that it does.
For both examples I gave—small thyroid masses, small kidney masses—it has been well documented that aggressive efforts to treat them, despite many being cancer, does not help most people. Isn’t that strange? Yet despite ourselves, we keep finding and removing them.
That’s the tricky thing with diagnostic tests. It’s terrifically hard to unsee something. For those who receive no benefit from treatment, only secondary harm results: surgical pain and complications, the anxiety of a scary diagnosis, and financial burden.
There are numerous non-intuitive examples like this in which only in retrospect do we realize patients have been harmed because a diagnostic test and its downstream actions were promoted to millions before confirming things worked as intended. This is why scientists and medical professionals are so obsessive about evidence and statistics. It’s really hard to know if something is hurting or helping if we rely on common sense.
The likelihood of benefit and the likelihood of harm matter tremendously. For example, if whole-body MRI is performed on a high-risk patient with a cancer-causing genetic syndrome, it is much more likely to create health benefits than if it were to be performed in the general population. This is one of the paradoxical things about diagnostic tests. It’s not just about test accuracy. Equally important is the people being tested, because baseline risk strongly influences the benefits.
Harm is often caused not by the test itself, but from actions taken to manage the information of unknown significance it produces. It is in this way that a seemingly harmless test can hurt people. We do tests to find things, and when we find things, we commonly act, even when we shouldn’t, because we aren’t rational decision-makers.
Direct-to-consumer testing will change how medicine is practiced. It empowers us to make personal decisions about our health and generates novel, complex information that will unlock scientific breakthroughs.
When buying one of these tests, we should pay attention to what the company is claiming. Is their test a curiosity, an entertainment product, a research tool, or clinical care? The lines are often intentionally blurry.
The need for scientific support, informed disclosure, and regulatory compliance increases as the test moves from curiosity toward clinical care. If the test has only been shown to provide information or to make a diagnosis, or has only been shown to improve health in patients with specific risk factors different from our own, we should be skeptical. As they say, buyer beware.
Many companies encourage us to assume their test improves our health. In such cases, the information we are buying may help us, hurt us, or be a placebo and do nothing at all.
