Ensure strict compliance with Covid testing guidelines, CM tells officials

New Delhi: After the Delhi High Court took serious note of the declining number of RT-PCR tests and the increasing number of rapid antigen tests in the Capital, especially in light of the high false-negative rate of the latter, Chief Minister Arvind Kejriwal on Wednesday directed health officials here to strictly follow COVID-19 testing guidelines as issued by the Indian Council of Medical Research (ICMR).

The CM took to Twitter and said, "Existing guidelines say that if any patient's antigen test is negative but has symptoms, RT-PCR test must be done on him. I directed the officers today to ensure strict compliance of these guidelines."

This comes after data presented to the high court showed that a marginal number of those testing negative in rapid antigen tests were being retested and of those being retested with RT-PCR tests, nearly 14 per cent coming back as positive for the contagious disease.

Given the low sensitivity (which increases chances of false -ves) of antigen tests and low availability of RT-PCR test kits, the ICMR had issued guidelines specifically stating that any symptomatic person testing negative on a rapid test be retested with RT-PCR to avoid the chance of missing out on false-negative cases.

Medical experts in the city continue to raise the issue of the inaccuracy of the rapid antigen tests amid directions as Delhi government prepares to tweak their interpretation of the guidelines, as per which they were conducting antigen tests on SARI (Severe Acute Respiratory Illness) patients as well. However, the ICMR has said only ILI (Influenza-like Illness) patients should be tested through rapid antigen tests and SARI patients should be prioritised for RT-PCR tests.

Dr Navin Kumar, Head of Clinical Microbiology and Infection Prevention at Manipal Hospital said that even though the difference in testing technique between rapid test and Real-Time Polymerase Chain Reaction (RT PCR) is not major, the accuracy of the result, however, varies. "Rapid testing has low sensitivity, which means it will not pick up many true positive cases," he told Millennium Post.

RT-PCR is a laboratory technique widely used in the diagnosis of genetic diseases and to measure gene expression in research. It has been globally recommended as the gold standard for diagnosing COVID-19.

Dr Kumar, who himself conducts COVID-19 tests said that during the trial or the performance of the test, the result is not shown as it should be. "The process is the same way we do rapid sampling for RT-PCR. However, it is the kit that is different for both," he added.

Dr LM Parashar, ENT Surgeon at Apollo Spectra Hospital echoed the same sentiment. "Rapid is a very easy test to do and the report also comes in 30 minutes. If the result comes out positive then there is every likelihood that the person is COVID positive, but if the report comes negative one can't be sure and should go for RT-PCR for prevailing symptoms," he said.

The high court also noted that given the Serological survey results of the city, it was imperative that the Delhi government follow testing guidelines to the T and ramp up RT-PCR testing. It said that the city had a capacity to conduct 11,000 RT-PCR tests daily but was clocking only around 5,000 every day.

An official in the health department said, "We were following the guidelines issued by the ICMR before too. If a person is symptomatic and tests negative we conduct an RT-PCR test. We have been aggressively testing from before."

District officials said that they have not received any fresh order or notice from the Delhi government with respect to this issue of rapid antigen testing having a relatively high false-negative rate.