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Originally Posted by SleepyButch
I wonder if this was referring to the second nurse who now is positive for the virus. I'm sure these two won't be the only ones who test positive before all is said and done.
Anyone know how soon you will test positive after exposure? Or do you have to start exhibiting symptoms first??
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I think this is good information and hope it answers some questions:
Tests for Ebola
A number of tests can be used to diagnose Ebola within a few days of the onset of symptoms, which can detect the virus's genetic material or the presence of antibodies against the pathogen.
The most accurate of these is likely the polymerase chain reaction (PCR) test, a technique that looks for genetic material from the virus and creates enough copies of it that it can be detected, Hirsch said. "PCR is a really definitive test," Hirsch said. It can pick up very small amounts of the virus.
>>>>>However, this test can be negative during the first three days an infected person has symptoms, said Dr. Sandro Cinti, an infectious-disease specialist at the University of Michigan Hospital System/Ann Arbor VA Health System.
"Somebody could be in the hospital for three to five days before a diagnosis [of Ebola] is confirmed," Cinti told Live Science. "The important thing is keeping the patient isolated until you can get to a diagnosis." Meanwhile, doctors will be running tests to rule out other diseases, such as malaria, which can be detected more quickly than Ebola, he said.
>>>>Another test for Ebola looks for antibodies produced by the body's immune system in response to the virus. Known as the antigen-capture enzyme-linked immunosorbent assay (ELISA), this test can take even longer than three days to give a positive result for an infected person, Cinti said. And antibodies can also be detected after a patient recovers, he added.
Once a patient is diagnosed with Ebola, scientists may attempt to isolate the virus -- which is a type of filovirus, known for their filamentlike shape -- by culturing it with living cells and examine it using electron microscopy. But culturing Ebola is very dangerous, and should only be done in a high-biosafety-level lab, Hirsch said. Culturing the virus is not a practical means of diagnosing infection, but may help researchers understand how the virus infects cells and test possible treatments.
So, given the severity of an Ebola infection, why wouldn't you test everybody with the remotest chance of having the disease?
A huge number of people come to the United States from Africa with fevers, Cinti said, and testing all of them for Ebola would drain hospital resources and raise unnecessary panic. "We really have to be clear and get good histories about exposure," he said. "It makes absolutely zero sense to test people who aren't from high-risk areas."
http://www.cbsnews.com/news/how-doctors-test-for-ebola/