Viral tests can detect whether or not a patient currently has COVID-19. Samples are taken from the respiratory system and then assessed in a laboratory.
The CDC has published guidelines on who should receive testing for coronavirus. State and local healthcare authorities have established their own decisions based on these and their own accessibility to tests.
Getting a Viral Test for Coronavirus
If an individual thinks they have been infected with coronavirus and wishes to be tested, they should contact their local surgery first. They will confirm the current availability of testing in the area and direct the caller to where they can report for testing. Priority may be given to those who are high-risk or displaying more moderate symptoms of coronavirus.
Once someone is referred for a viral test for coronavirus, a clinician will usually collect a sample from the inside of the nose or the back of the throat. This detects any viral RNA (the genetic material of the virus) in the patient’s cells. Laboratists will perform a test to convert the viral RNA to DNA. The test is known as a reverse-transcription Polymerase Chain Reaction (PCR). The DNA is replicated until there are enough versions to detect the presence of the virus’ genome.
Receiving the results from a viral test for COVID-19
The time it takes to receive the results from a viral test for coronavirus takes from less than an hour to 48 hours. If the sample can be examined on-site, then results can be as fast as one hour or less. If they are sent to a laboratory then it may take up to two days.
At the time of testing, the patient should ask their clinician how they will receive the test results. They will be able to advise on the anticipated timeframe.
If a patient tests positive for COVID-19, they will be advised of the next step. For mild cases, that will require self-isolating at home for at least 14 days whilst monitoring symptoms. The infected individual should avoid contact with anyone they live with and members of the public.
The clinic should ask about anyone who the infected individual might have come into contact with who may have contracted the virus. This is important for curbing the spread of coronavirus.
If an individual tests negative for COVID-19 this means that they most likely were not infected at the time they gave their sample. If symptoms of coronavirus persist, they may have been tested too early. A viral coronavirus test cannot always detect the virus at its onset.
Testing negative for COVID-19 does not indicate that the patient is immune to the virus. They may get infected at a later date.
Viral tests may yield a false-negative result. Reasons for this may be that the clinician didn’t collect enough samples containing the virus or took the sample incorrectly.
False negatives for coronavirus may also occur if the person tested too early or too late in their course of the infection. Perhaps there was not enough of the virus in their cells.
Leaving a sample too long prior to being examined can lead to the breakdown of the viral RNA. This may also yield a false negative.