Figure 1.

Timelines for optimal use of different diagnostic tests for COVID-19 detection and host response

The optimal timeframe during which molecular and antigen tests can be used for confirming the clinical diagnosis in a patient infected with SARS-CoV-2, based on the lower limits of virus detection for these tests, the dynamics of viral shedding, and the period of infectiousness over the course of infection as reported in the peer-reviewed literature.16, 17, 18, 19, 20, 21, 22, 23, 24 Serology tests to detect host response to infection are usually used 7 days or more after symptom onset to determine exposure or past or recent infection and are primarily used for surveillance. Ag-RDT=antigen rapid detection test.