Diagnostic tests for COVID-19 We have three different tests for the diagnosis of COVID-19 , those that detect coronavirus RNA, those that detect a specific protein (antigen) of COVID-19 and those that detect the body's response to the virus, that is Antibodies. In COVID-19, the test we use to detect RNA is the Polymerase Chain Reaction (PCR by its initials in English). Without getting lost in details, the PCR detects RNA sequences unique to SAR-Cov-2. It is used to identify people who are infected by the virus (have many or few symptoms) and has been the key to the beginning of the pandemic. Until now, it has been the only test available to confirm cases of COVID-19 in Spain and other countries. It is the most reliable (fewer false positives and false negatives) and is recommended by health authorities such as the WHO. The sampling is very simple, a simple swab and make a nasal and / or pharyngeal smear. Logically, it has its drawbacks. The main one ...