This NYT article just adds to the growing list of confusing, misleading media coverage of COVID19.
Your Coronavirus Test Is Positive. Maybe It Shouldn’t Be
New York Times, Aug. 29, 2020
The amount of media confusion surrounding COVID19 is staggering. In addition to this article there was the recent confusion about what the CDC was trying to say about testing last week — that testing too soon after a possible exposure can be misleading.
It’s true that the PCR-based tests, like the test that Bedford Research performs, are very sensitive — it is highly unlikely that 20 copies of SARS-CoV-2 (the viral load that BRF testing can detect) would indicate a contagious person. Rapid instruments (like the one Abbott sells) are likely to be far less sensitive, and maybe more useful, to indicate risk of contagion. They will only detect a higher viral load, but that is most likely perfect for detecting contagious individuals.
So, if a hospital has someone in an ER to triage, risk of contagion is the first order of concern, and a rapid test would be very helpful. Same for schools trying to limit spread by an asymptomatic carrier.
Nonetheless, a more sensitive test is clinically far more valuable — a beginning infection, the end of an infection, etc. Especially in circumstances where close physical contact is necessary — day care centers, phlebotomy stations, long term care facilities, barbers, etc.
Those working in long term care facilities and ICUs — are frustrated by negative tests when the patient has all the symptoms of COVID19. Hence, once the immune system kicks in (which is when fever, cough, etc. starts), virus titers drop precipitously, and a sensitive test may be the most useful way to be able to classify the patient.