Saliva-based test can give quicker result: study

Saliva-based rapid antigen test (RAT) could be effective, faster and economical in the diagnosis of COVID-19, a study has found.

Chennai Dental Research Foundation (CDRF), Voluntary Health Services (VHS) and Ragas Dental College and Hospital conducted the study. The results achieved the minimum standards set by the Indian Council of Medical Research (ICMR). It recorded a sensitivity of 56% as against the 50% required by ICMR and specificity of 100%, compared with 95% set by ICMR, according to a release.

Gunaseelan Rajan, president of CDRF, said the biggest advantage of RAT was that it was faster than RT-PCR test. “It is safe. One can take up a self-test at home or office. Our research has shown that using saliva for RAT was rapid and effective. It could be utilised for mass screening, rapid screening, and by dentists and ENT doctors as it can detect the virus in 10 minutes,” he said. He said they had written about the findings to the Centre, while the results were accepted for publication in an international journal “Oral Diseases” in February 2021.

According to the study, 27 RT-PCR positive and 10 RT-PCR negative whole mouth fluid (WMF) samples were selected. The presence of SARS-CoV-2 antigen was tested using a commercially available nasopharyngeal swab RAT from Korea. It found that the 10 RT-PCR negative WMF samples were RAT negative, and of the 27 RT-PCR positive WMF samples, 15 were RAT positive. It said that RAT can detect SARS-CoV-2 antigens in 78% of cases from WMF in a reliable manner.

K. Priya, scientist and head, Department of Clinical Research, VHS, said RAT took 15 minutes as against a minimum of three hours for RT-PCR testing. The researchers adopted a commercially available kit for saliva testing. A positive saliva test was confirmatory but a negative test should be followed up by a RT-PCR test, they added.

Another study found that the use of certain mouthwashes reduced the burden of virus in the saliva and respiratory droplets. This could be beneficial in dental practices.

Yuvraj Gupta, chief operating officer, VHS; N. Kumarasamy, director, VHS-IDMC; and K. Ranganathan, Ragas Dental College and Research Director, CDRF, were present.

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Printable version | Apr 20, 2021 7:53:37 AM |

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