How is RT-PCR so sensitive?
In addition, the virus genes targeted with the primers are amplified over a billion times during the RT-PCR reaction. This technique is therefore analytically very sensitive.
If we take the variable carriage of the virus at the nasopharyngeal level into account, as well as the variability from the taking of the sample, the overall results are sensitive to 95% of RT-PCR (i.e. from 100 samples taken from patients with COVID 19, more than 95 are said to have a positive RT-PCR result).
The RT-PCR technique performed on oropharyngeal and nasopharyngeal swabs remains the reference diagnostic method. Priority should be given to qualified operators taking the sample, to optimize the quality of the sample collected, and to take into account the patient’s clinical signs for the interpretation of the test result.