Chennai: An eight month long study to determine the feasibility of the Saliva-based COVID-19 Rapid Antigen Test (RAT) has revealed that the test is less expensive, faster and safer than the RT-PCR tests which are widely used in India. While saliva-based RAT are approved by the Food and Drug Administration (FDA) in the US, this test is not approved by the Indian Council of Medical Research (ICMR). However, the nasal and oral RAT are permitted in India.
According to the Doctors, this study was done to establish the efficacy of the test among the Indian population, as not many studies were performed in India on this method of saliva-based testing.
“In an RT-PCR test (highly sensitive), even samples of those who have recovered from COVID-19 might be shown as positive, as it detects even the dead virus. However, in such cases, there is no risk even if one is shown as positive, as the dead virus (from months ago) does not infect or spread. But in case of the saliva RAT, a positive result means that the person is infective (has the potential of spreading the virus),” Dr. Gunaseelan Rajan, President, Chennai Dental research Foundation told Zee Media.
The team has stated that the COVID-19 saliva test study results are better than the minimum standards set by ICMR - Sensitivity of 56% (50% minimum by ICMR) and Specificity of 100% (95% minimum set by ICMR). These research results have been accepted in the international journal ‘Oral Diseases’ in Feb 2021.
Doctors part of the study are of the opinion that Saliva-based tests will be very effective for screening programmes, community testing and whenever quick results are needed. They say that such tests can be useful at dental and other specialty clinics, before treating the patients, to know if they visitors are COVID-19 infective and the spread the virus can be curbed.
Dr. K. Priya, Scientist & Head, Department of Clinical Research, VHS says that the saliva-based is indicative in nature and identifies only active COVID-19 cases and not the early stage infections. “If an individual’s saliva test returns positive, then it can be confirmed as Covid-19, but in case the test returns negative, it is safer to take an RT-PCR test to determine whether the person has an early stage Covid-19,” she said.
With COVID-19 cases seeing a gradual spike in parts of India, the Doctors behind this study opine that the Government and ICMR consider permitting Saliva-based RAT, which are simple, take barely minutes to give results, are almost 40% the cost of an RT-PCR test. The saliva tests can also be done at home and does not require any assistance.
The study using the South Korean SD Biosensor test was conducted by a team of doctors from Chennai Dental Research Foundation (CDRF), recognized by Department of Biotechnology (DBT), Ragas Dental College & Hospital and Voluntary Health Service (VHS) Hospital.