Positive numbers are written with no sign or a '\({+}\)' sign in front of them and they are counted up from zero to the right on a number line. Any number below zero is a negative number.

They're really just meant to be read as a binary: positive or negative. “We have some of these tests in our lab that we run ...

to reduce your risk of a false negative result. This applies whether or not you have symptoms. Essentially, a positive result ...