Timely and accurate diagnosis is a crucial component in the management of COVID-19. The gold standard of diagnosing SARS-CoV-2 infection is real-time reverse transcription polymerase chain reaction (RT-PCR). However, due to certain limitations of RT-PCR, “Antigen detecting Rapid Diagnostic Tests (Ag RDTs)” was considered and implemented.
Ag RDTs detect the presence of SARS-CoV-2 viral protein from respiratory specimens (such as nasopharyngeal or nasal swab specimens, saliva) and indicate active infection with the results generated in 10 to 30 minutes. Due to its simplicity of use, rapid turnaround time, cost-effectiveness, accessibility and scalability, Ag-RDTS offers the ability to extend test capacity in non-lab decentralized locations.
In 11 September 2020, World Health Organization (WHO) released interim guidance for SARS-CoV-2 rapid antigen tests stating that Ag-RDTs meeting the minimum performance requirements of sensitivity ≥ 80% and specificity ≥ 97% compared to a RT-PCR reference assay can be used for the diagnosis of SARS-CoV-2. Rapid antigen tests are more sensitive in patients with high viral loads (Ct values £25) reflecting 1-3days before symptoms onset and early symptomatic phase (i.e. within the first 5-7 days of the illness). Thus, rapid antigen tests are intended for early diagnosis and interruption of transmission chain by identifying and cohorting the most infectious cases.
According to World Health Organization (WHO) and United States Centers of Disease Control and Prevention(U.S.CDC), Ag-RDTs can be used to respond suspected COVID-19 outbreaks by screening high-risk individuals, to monitor disease incidence trends in communities if the results can facilitate effective infection control and for contact tracing where there is widespread community transmissions.
To date, WHO has approved a total of three rapid antigen tests; two from nasopharyngeal swab specimens and another from nasal swab specimens. Abbott Panbio COVID-19 Antigen Rapid Test Device of Nasopharyngeal and Nasal Swab Types is intended to detect SARS-CoV-2 antigen from individuals who meet COVID-19 clinical and/or epidemiological criteria including asymptomatic individuals at-risk or with a suspected exposure. It can be deployed in any laboratory and non-laboratory environment with the test performance of sensitivity ≥ 91% and specificity 99.8%.
References:
https://www.cdc.gov/coronavirus/2019-ncov/lab/resources/antigen-tests-guidelines.
- Ma Moe Phyu Thet Htwe: 09 422 466 414
- Dr. Lwin Thandar May 09 441 926 363