My friend Anish Koka, a cardiologist, wrote a beautiful review of COVID testing over at the HealthCareBlog.
The great pandemic is wreaking havoc, we are told, because the nation is not testing enough. The consensus from a diverse group that includes public health experts, economists, and silicon valley investors is that more testing will allow the country to restart the economy and do it safely.
No, it’s not quite that easy, Anish writes. You will learn a lot from his long column.
You might wonder why a COVID post from a cardiologist is worth reading. First, since COVID is novel, there are few true experts. Second, COVID tests are similar to cardiology tests in many ways.
Take a stress test; these are not black and white. A young patient with no risk factors and unusual symptoms who has a positive stress test probably has a false positive. A patient who smokes and has diabetes and typical chest pain who has a positive stress test probably has a true positive.
COVID tests are like that too. You have to think about likelihoods. You have to know the viral swab has problems with false negatives–you could have COVID infection and still test negative. The antibody tests have the other problem: you could test positive and not actually have the antibodies.
One of my hopes from this terrible pandemic is that it makes patients and doctors smarter about uncertainty. COVID19 is one giant thinking exercise. And if we think a lot we may collectively become smarter about healthcare.
The next time the doctor says you “need” some test, you might think about asking about the rates of false negatives or false positives. You might think what if I don’t get this test?
And since your mind is so sharp from all this thinking, you might think: what are the potential downsides, the unintended consequences of having this test? I have seen a simple $25 dollar ECG lead people into an odyssey of healthcare folly.
Dan Morgan, MD and I wrote about the pitfalls of cascades from testing in the open access journal JAMA Network Open.