BENGALURU: The State government on Thursday issued instructions to overcome false negative cases reported through RT-PCR tests by extending diagnostic methods to Covid-19-like syndrome for early detection and treatment.A circular issued by the Jawaid Akhtar, Additional Chief Secretary, Department of Health and Family Welfare, recommended the use of CT Thorax scan findings and other laboratory investigations, to detect Covid-19 syndrome or Covid-19 probable cases “so that we can initiate treatment similar to Covid-19 confirmed cases as early as possible to reduce the spread of infection, morbidity and mortality”.
This test has been approved by the Joint Experts Committee, Rajiv Gandhi University of Health Sciences and the technical advisory committee of the Department of Health. All health establishments treating Covid-19 have been directed to strictly adhere to the tests to reduce Covid-19 mortality.Viral infections manifest as varied clinical syndromes which are similar to many other pathogens, hence, it is not possible to confirm the diagnosis of patients with Covid-19 or influenza infection without a diagnostic test.
The circular states that in spite of clinical-radiological symptoms indicating symptoms of Covid-19, the RT-PCR test — considered the gold standard in testing for Covid-19 — may turn out negative.The sensitivity and specificity of RT-PCR tests ranges between 60-7%, raising the possibility of missing positive cases through ‘false negative’ results, which allows those who are actually positive to walk out with a ‘negative’ report in hand.
The standard Q Covid-19 rapid antigen detection test, recommended by the Indian Council for Medical Research, has shown an ability to detect true ‘positives’ ranging between 50.6-84% and an ability to detect true ‘negatives’ ranging between 99.3-100%. However, the circular states, studies have shown that the CT Thorax test has greater sensitivity ranging between, 86% and 98% for detecting ‘positive’ cases, while having a lower false-negative rate than the RT-PCR test.