Thread by @michaelmina_lab

Did you know

A test that is 100% accurate to detect infectious ppl will only *APPEAR* to be 30%-60% sensitive when compared to PCR-particularly asymptomatics

Why?

PCR stays positive LONG AFTER contagious period

for Public Health, PCR is NOT Specific - it’s a wrong comparison

Although rapid tests are not 100% sensitive to detect infectious levels of virus, they are >95% and do approach 100% for “superspreader” levels of virus.

We just (ignorantly) continue to compare them to PCR - which has led to massive confusion.

2/

This issue with PCR has caused us to isolate millions of ppl who were no longer infectious and lead contact tracers to trace and quarantine many many millions who were never exposed.

3/

For public health, we need tests that are not only sensitive, but as importantly are highly SPECIFIC to what it is we are trying to detect - INFECTIOUS ppl.

PCR excels in the former but fails miserably when it comes to specificity to detect infectiousness.

4/

For testing in a pandemic - we MUST let the goal determine the gold-standard

We have thus far used a gold standard borrowed from medical diagnostics and it’s been disastrous

We need gold standards for public health testing. Where speed and accuracy for infectiousness matter

5/

And here is a graphic to demonstrate this concept:

https://twitter.com/michaelmina_lab/status/1391892124937998336?s=20