Re:Covid-19, duration of viral shedding, and infectiousness:...
by thinkingemote on Monday November 23, 2020 @07:21AM
(#25185958)
Do tests test for the RNA or the live virus?
[ Parent
| on HN ]
Re:Covid-19, duration of viral shedding, and infectiousness:...
by westwing on Monday November 23, 2020 @08:04AM
(#25186320)
The PCR test amplifies RNA fragments. If after a certain amount of replication cycles the amount of detected RNA crosses a threshold, it is considered a positive.
A positive PCR test does not imply infectiousness. Many people who have a positive test are not just asymptomatic, they are not really infected to begin with.
A negative PCR test does not rule out disease. Some people who have a clinical diagnosis of COVID may produce a negative PCR result.