Nasopharyngeal swab specimen and real-time reverse transcription-PCR (rRT-PCR) for SARS-CoV-2 (COVID19)is the method of testing.There may be co infection with Other viruses. What isthe sensitivity and specificity of the method ?
Sensitivity approx. 60% and Specificity between 90-100%....
Sample collection method should not be faulty & test is to be conducted in a BSL3 laboratory.
For better results, lower respiratory tract samples (ET aspirates, BAL etc.) are preferred.
The accuracy of SARS-CoV-2 tests depends on the standards of kits used, the experience of person taking the sample, and the timing of the sampling from a suspected patient (Best up to 2 days before symptoms up to 8 days later, positivity decreasing later on).
Read following links
1. Article Detection of SARS-CoV-2 in Different Types of Clinical Specimens
2. https://www.cebm.net/covid-19/comparative-accuracy-of-oropharyngeal-and-nasopharyngeal-swabs-for-diagnosis-of-covid-19/
3.Article Negative Nasopharyngeal and Oropharyngeal Swab Does Not Rule...
These tests are 60% accurate, doctor told me, I got tested myself 2 days before. Even I was negative they advised me to watch for any symptoms. Results came in 18 hours later.
When people say, I was negative in first test and virus came back in second test. In fact, first test was inaccurate and was false negative, in my opinion