The Indian Council of Medical Research (ICMR) has recently approved a rapid antigen detection assay for the diagnosis of COVID-19 using nasal samples. Developed by SD Biosensor, Standard Q COVID-19 Ag detection kit is a rapid chromatographic immunoassay for the qualitative detection of specific antigens to SARS-CoV-2.
The point-of-care test can be performed outside the conventional laboratory setting and was found efficient to deliver a quick diagnostic result, according to the ICMR. The kit comes with an inbuilt COVID-19 antigen test device, a viral extraction tube with viral lysis buffer and a sterile swab for sample collection. Once the sample is collected in the extraction buffer, it will be stable only for one hour. Hence, the antigen test is recommended to be conducted at the site of sample collection in the healthcare setting.
While the standard RT-PCR test takes a minimum of 2-5 hours including the time taken for sample transportation, the rapid antigen detection test interpreted the result in 30 minutes, the ICMR advisory stated.
The kit has been approved in India based on an independent two-site evaluation conducted at the ICMR and AIIMS. According to the study, the findings showed a high specificity ranging between 99.3% and 100% at both the sites, while the sensitivity of the test ranged between 50.6% and 84%, depending upon the viral load of the patient.
As of now, the kit will be used in containment zones or hotspots and healthcare settings. The ICMR has advised that the test will be performed onsite under strict medical supervision and maintaining the kit temperature between 2° and 30°C.
Since the virus tends to shed for longer periods than adults, it may result in differences in sensitivity between adults and children, points out the company. A negative test result may also occur if the level of an extracted antigen in a specimen is below the sensitivity of the test or if a poor quality specimen is obtained.