Originally Posted by
JDNSW
Precisely! A positive test shows you are infected (although there is always the possibility of a false positive due to contamination), but a negative result does not show you are not infected. Not only are the tests not perfect, but it is known that an infected patient may not shed any virus particles for several days after becoming infected - although the average incubation period is five days (but up to fourteen or even more in a very few cases), virus shedding, and hence the ability to detect the infection, only starts two or three days before symptoms in most cases, although this can be longer.