This study aims to analyze the usefulness of rapid tests, especially: a) as a diagnostic test in people attending care for nonspecific, respiratory symptoms, in emergency services of referral hospitals b) as a diagnostic test in contacts of known patients. c) as a diagnostic test to differentiate influenza from COVID-19 in the circumstance of an overlap of both viruses in the community. d) In the 3 cases, the gold standard would be the RT-PCR test for influenza and for SARS-COV-2 performed in the usual laboratory following the officially approved technique in Mexico. If the test were in saliva, it would also be much more accepted and could come close to performing a test at home that would greatly facilitate the diagnosis. So it is important to see the performance of a saliva test.~As an observational (cross-sectional) study in the emergency services of participating hospitals, receiving patients with COVID-19 and influenza, aiming to evaluate the diagnostic performance of the rapid antigen detection test for COVID-19 both in nasal sampling and saliva, in patients attending emergency services in the 2020-2021 winter season, performed on site, compared to the gold standard (RT-qPCR).
An observational (cross-sectional) study in the emergency services of participating hospitals, receiving patients with COVID-19 and influenza, aiming to evaluate the diagnostic performance of the rapid antigen detection test for COVID-19 both in nasal sampling and saliva, in patients attending emergency services in the 2020-2021 winter season, performed on site, compared to the gold standard (RT-qPCR).