Study Raises Questions About False Negatives From Quick COVID-19 Test

[sl8]

From https://www.npr.org/sections/health-shots/2020/04/21/838794281/study-raises-questions-about-false-negatives-from-quick-covid-19-test

Study Raises Questions About False Negatives From Quick COVID-19 Test

April 21, 2020 6:07 AM ET
Rob Stein

The fastest test being used to diagnose people infected with the coronavirus appears to be the least accurate test now in common use, according to new research obtained by NPR.

Researchers at the Cleveland Clinic tested 239 specimens known to contain the coronavirus using five of the most commonly used coronavirus tests, including the Abbott ID NOW. The ID NOW has generated widespread excitement because it can produce results in less than 15 minutes.

But the ID NOW only detected the virus in 85.2% of the samples, meaning it had a false-negative rate of 14.8 percent, according to Dr. Gary Procop, who heads COVID-19 testing at the Cleveland Clinic and led the study.

"So that means if you had 100 patients that were positive, 15% of those patients would be falsely called negative. They'd be told that they're negative for COVID when they're really positive," Procop told NPR in an interview. "That's not too good."

[...]

[Squinch]

1. Apparently the current longer tests have plenty of false negatives too.

I only say that because of anecdotal observation of a number of acquaintances who tested negative before they tested positive.

If this trst allows us to get 85% out of circulation and do it quickly, lets not scrap it till something better comes along.

[Pacifist Patriot]

2. "not too good" is quite the understatement

[Igel]

6. How's "as good as the rest."

Because for all the screaming about needing tests, that's about where the tests are. Some are worse, some are a bit better.

An NPR report pointed out others are 100-95% reliable. Others point out that often the manufacturers are the source of those numbers, and it's easy to game the data reporting system--so the reliability numbers themselves aren't reliable.

[Pacifist Patriot]

7. I haven't seen any numbers I'd trust.

We have bad information about absolutely everything. Personally, I'm just acting on "this is bad and probably going to get worse." The presumed numbers and real numbers are quite likely going to bear that out, so I'm not splitting hairs over data.

I'm just doing what little I can to keep the numbers as low as possible -which in the grand scheme of things may not be much, but in aggregate with others taking an abundance of caution maybe we can save some lives. We'll never know how much our isolation helped, we can only assume that it will in some respect.

People making life and death decisions based on bad information are tilting at windmills. We know we don't know an awful lot and we don't know what we don't know even more. This is a rung of hell for analysts like me.

[safeinOhio]

3. Trump Test. It's only a

branding problem.

[Mike 03]

4. 14.8% is bad, but isn't this (believe it or not) superior some of the other

tests in common use now? I thought I heard false positive rates of 20 - 30%.

[elias7]

5. That's actually better than the current influenza swab

Which is around 70% in my clinical experience (CDC says 50-70%, other sources vary)