COVID-19: ICMR Recommends Combination Of Rapid Antigen Test And RT-PCR Test

NEW DELHI: Indian Council of Medical Research, ICMR has recommended the use of rapid antigen test kits for diagnosis of COVID-19 in containment zones and healthcare settings in combination with the RT-PCR test.

The kits will allow faster diagnosis without laboratory examination. A rapid antigen test kit is a rapid chromatographic immunoassay for a qualitative detection of specific antigens to SARS-CoV-2. It has been developed by a South Korea based company.

ICMR said in an advisory that suspected individuals who test negative for COVID-19 by rapid antigen test should be tested sequentially by RT-PCR to rule out infection, whereas a positive test should be considered as a truly positive and does not need reconfirmation by RT-PCR test.

The Standard Q COVID-19 Ag detection can be interpreted as positive or negative after 15 minutes of putting the sample into the well by the appearance of test and control lines, which can be read with a naked eye, requiring no specialized equipment.

The maximum duration for interpreting a positive or negative test is 30 minutes. After that, the test strip should be discarded.

In view of its high specificity while relatively low sensitivity, ICMR recommends the use of Standard Q COVID-19 Ag detection assay as a point of care diagnostic assay for testing under containment zones and healthcare settings in combination with the gold standard RT-PCR test.

The ICMR further said, “the Standard Q COVID-19 Ag rapid antigen detection test has a very high specificity i.e. ability to detect true negatives. Specificity ranged from 99.3 to 100% at the two sites. “Sensitivity of the test (i.e. ability to detect true positives) ranged from 50.6% to 84% in two independent evaluations, depending upon the viral load of the patient. Higher viral load correlated with higher sensitivity”.

The ICMR further said that in healthcare settings, all symptomatic ILI patients presenting in a healthcare setting and are suspected of having COVID-19 infection, asymptomatic patients who are hospitalized or seeking hospitalization, in the high-risk groups such as patients undergoing chemotherapy, immunosuppressed patients including those who are HIV positive, patients diagnosed with the malignant disease; transplant patients, elderly patients (>65 yrs of age) with co-morbidities as mentioned in the containment zones can be tested.

“We can protect the susceptible population by giving a vaccine – which we do not have, or decrease infectiousness of a person by medications – which also we do not have. Since the vaccine is not yet anywhere around, the only way open to us is prevention: using masks, keeping physical distance, washing hands often. As numbers of cases increase it would be very resource-intensive to do contact tracing and quarantine. The aim should be mitigation – treatment of all which need hospitalization,” said Lalit Kant, a scientist and former head of epidemiology and communicable diseases at the Indian Council of Medical Research (ICMR).

from League of India