Diagnosis: Clinical considerations for care of children and adults with confirmed COVID-19

ABSTRACT

What You Need to Know ;When testing for current COVID-19, the CDC recommends that clinicians use viral tests that detect SARS-CoV-2, not a serologic test, which detects antibodies. ;Testing is important to identify and help reduce the spread of COVID-19 (see diagnostic tests for COVID-19). Viral tests, including NAAT and antigen tests, are used to diagnose COVID-19. Antibody tests (serology) are not indicated to diagnose a current infection. NAATs that use reverse transcription-polymerase chain reaction (RT-PCR) technology to detect SARS-CoV-2 ribonucleic acid (RNA) are highly sensitive and specific and detect SARS-CoV-2 RNA in respiratory specimens. Clinical RT-PCR tests for SARS-CoV-2 that determine the cycle threshold (Ct) value are not validated to estimate viral load, and the NIH recommends that Ct values may be considered only in consultation with an infectious disease expert. ;;SARS-CoV-2 antigen tests typically provide rapid results and are less expensive than NAATs, but they are generally less sensitive than NAATs. Antigen tests for SARS-CoV-2 use immunoassays to detect the presence of a specific viral antigen in respiratory specimens, and include point-of-care, laboratory-based, and self-tests. A negative antigen test in persons with signs or symptoms of COVID-19 should be confirmed by NAAT. For more information, see the Antigen Test Algorithm. ;;Specific recommendations on testing strategies in various clinical situations and information on SARS-CoV-2 molecular and antigen assays (including COVID-19 self-tests) that have received U.S. Food and Drug Administration (FDA) Emergency Use Authorization (EUA) are available, see FDA’s COVID-19 In Vitro Diagnostics EUAs, CDC’s Overview of Testing for SARS-CoV-2, CDC’s Interim Guidance for Antigen Testing for SARS-CoV-2, and the NIH’s Testing for SARS-CoV-2 Infection which describes testing recommendations, including guidance on the use of Ct values.