COVID-19 rapid antigen test
COVID-19 rapid antigen tests or RATs, also frequently called COVID-19 lateral flow tests or LFTs, are rapid antigen tests used to detect SARS-CoV-2 infection (COVID-19). They are quick to implement with minimal training, cost a fraction of other forms of COVID-19 testing, and give users a result within 5–30 minutes. RATs have been used in several countries as part of mass testing or population-wide screening approaches. Many RATs can be used for self-testing, in which an individual "collects their own specimen… and interpret[s] their test result themselves".
| COVID-19 rapid antigen test | |
|---|---|
Negative (left, showing Control line) and positive (right, showing Control and Test lines) results | |
| Synonyms | SARS-CoV-2 or COVID-19 antigen test, rapid antigen detection test (RADT), lateral flow test (LFT), lateral flow device (LFD), antigen-detecting rapid diagnostic test (Ag-RDT), antigen rapid diagnostic test (Antigen-RDT), point of care (POC) test, rapid test |
| Purpose | To diagnose SARS-CoV-2 infections (COVID-19) |
| LOINC | 94558-4, 95209-3, 96119-3, 97097-0 |
False positives are very rare; the tests' specificity is 98%-99%. However, the tests have a sensitivity of 70%-72%, which is lower than COVID-19 polymerase chain reaction (PCR) tests' sensitivity of 88%-96%. Despite this, COVID-19 RATs remain valuable in finding people who would otherwise not know they were infected, helping to prevent further transmission. The tests are more sensitive in the symptomatic and transmissive stages of disease when the viral load is higher.