SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; COVID-19: coronavirus disease 2019; NAAT: nucleic acid amplification test.
* Symptoms consistent with COVID-19 include fever and/or respiratory tract symptoms (eg, cough, dyspnea, sore throat, rhinorrhea/nasal congestion), as well as smell or taste disturbances, myalgias, headache, and diarrhea. Many individuals only have common cold symptoms. There are no specific clinical features that can reliably distinguish COVID-19 from other viral respiratory infections. Refer to other UpToDate content for additional details.
¶ For individuals who are willing to repeat testing with an NAAT, we suggest this approach given its greater sensitivity.
Δ Positive antigen tests generally do not warrant confirmation, even in settings of low prevalence. However, it is reasonable to confirm a positive antigen test with an NAAT when the diagnosis is suspect (asymptomatic individual with no known exposure) and prevalence is very low (eg, <1%); in that case, a negative NAAT would indicate no infection.
◊ A negative SARS-CoV-2 test does not rule out the possibility of subsequent development of infection; thus, individuals with a recent exposure to SARS-CoV-2 may still need to continue precautions (eg, wearing masks in public) despite a negative test, depending on the timing of testing. Refer to other UpToDate content on precautions following SARS-CoV-2 exposure.
§ If antigen tests are used in situations where the likelihood of SARS-CoV-2 is low (eg, testing of an asymptomatic individual who has had no known exposure and lives in a community with low infection rates), a negative antigen test can be interpreted at face value. Individual antigen tests performed for serial screening and antigen tests performed prior to a specific event generally do not need to be repeated if negative.