How long does it take for the results of nasopharyngeal swab PCR for COVID19 to appear ?
I mean after how many hours from taking the sample by the lab not after catching infection.
And does it differ from technique or machine or kits to another ?
Are there kits or lab tachniques faster than others ?
At minimum, it needs to take about 45 minutes for RNA extraction + 90 minutes for PCR. In reality, it depends largely on how the samples get queued and batched and sit around, until somebody gets time to deal with them. Those logistical issues are highly variable and can add days, depending on circumstances.
Hello
A simple PCR is not strong enough to be a detection method indeed. The better option as diagnostic kit are based on qPCR with a 3-channel machine. RNA extraction would take around 45 min as John Schloendorn said. Then cDNA synthesis and amplification (2 in 1 reaction) may take around 120 min (depends on the machine). I can say, give or take 3 H. This was for 1 sample, in reality you would use the maximum capacity, perhaps a dozen or more samples. It may add another extra hour to the overall process. Still the results of qPCR is not comparable with other ELISA based methods for this specific virus. Other immune-based methods are much faster and it turned out to be more accurate for COVID-19. Although in qPCR you may increase the volume of template to the max, do a triplicate reaction and with maybe doubling the volume of reaction will give you the better results in terms of false negatives. You may think about costs as well!
The CDC recommends a COVID-19 test called a nasopharyngeal swab. The technician will put a special 6-inch cotton swab up both sides of your nose and move it around for about 15 seconds. It won’t hurt, but it might be uncomfortable. They’ll send the swab to a lab to test the material from inside your nose.
Other COVID-19 tests include swabs of:
Your mouth and throat (oropharyngeal)
The middle of your nostrils (nasal mid-turbinate)
The front of your nostrils (anterior nares)
If you have a cough with mucus, called a “wet” or “productive” cough, your doctor might want to test some of what you can cough up.
A blood or “serology” test can also look for antibodies. Your body makes them when you’ve had an infection.
A swab test can tell only if you have the virus in your body at that moment. But a blood test shows whether you’ve ever been infected with the virus, even if you didn’t have symptoms.
It may take a lab about 24 hours to run your test. But you might not get your results for several days.
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