It depends on what you are testing for, the environmental conditions, conditions of the reagent, etc.
Quick results for some Virus are reliable 99% of the time. Meaning a false positive is more likely to need more extensive testing. HIV results are available in 20 minutes.
A more complicated less studied Virus would most likely need more time.
That said - if “they” can test in for this in such a short period of time, why are the results not yet available for Wash. D.C. And Maryland - or did I miss that?
The scary answer is the CDC has probably seen hundreds of Liberians with Ebola here in America and this guy really DIDN’T behave like the rest.
I missed the results on those, too.