What Are the Limitations of Rapid Diagnostic Testing?

Lilian Abbo, MD, chief, infection prevention & control and antibiotic stewardship, Jackson Health System, associate professor of clinical medicine, Division of Infectious Diseases, Miller School of Medicine, University of Miami, discusses some of the limitations of rapid diagnostic testing.

Interview Transcript (slightly modified for readability)

“The limitations of rapid diagnostic testing is a very broad question. There are different diagnostic tests, and they, again, should be used depending on what disease you’re treating and what’s your context.

For example, we have rapid viral PCR panels that detect 20 targets. You do a swab in someone’s nose and you want to know what virus they have. Well, sometimes, this test is very useful for patients who are immunosuppressed, [like] bone marrow transplant child or adult [patients] or solid organ transplant patients, or someone undergoing cancer chemotherapy, they’re neutropenic. [This test] really helps me know what kind of virus they have, especially [when] they’re in the hospital. I want to avoid cross-transmission [or] horizontal-transmission spread of this virus to other patients (for example, if we have [patients with] respiratory syncytial virus, or if I have [a patient with] human metapneumovirus), and I also don’t want the healthcare personnel to get sick.

So, identifying what pathogen it is helps me do infection prevention target therapy. If I [want to] use the same test in someone who’s completely healthy, like you or me, and we just walk in to see our primary care doctor with a runny nose and a little cough and fever, and we do the same 20-target viral panel, [we have to keep in mind that] it’s a very expensive test. The question is, do I really need to know which one of these 20 viruses I have, when the treatment is going to be ‘go home, get rest, and drink some chicken soup’?

So, you really need to look at what’s the cost of the test, what’s the value that I’m going to get, and is it really going to change my management? You have to be very conscientious, because this test costs money, and you only want to use the [test] in the context you’re going to be able to act on the results. They have to be actionable, and the information has to be useful. So, you have to be very careful.”