January 01 2021 at 06:38 PM by Samikshya Joshi
CAN SALIVA ACTS AS A DIAGNOSTIC TOOL FOR COVID-19?
The ICMR-Regional Medical Research Centre (RMRC) here has found an alternate and more convenient diagnostic tool - saliva - to act as a substitute for the nasal/throat swab sample now being used to test for SARS-CoV-2. Saliva is a reliable tool to detect SARS-Cov-2 by RT-r-PCR analysis
A paper on this topic has been accepted by the Journal of Medical Virology, a reputed international journal.
At present, nasopharyngeal swab or NPS is collected by health workers and medical staff for the Covid-19 test. If saliva is considered for the test, it makes the collection of the sample easier. Anyone can collect his/her saliva in a protected box and send it to a testing facility. This will reduce chances of infection among health workers and those getting tested won’t have to go through the discomfort of nasal swab collection.
The study, led by ICMR-RMRC Bhubaneswar director Sanghamitra Pati and senior scientist Debdutta Bhattacharya analyzed the feasibility of using saliva for the diagnosis of SARS-CoV-2. “A total of 74 samples of Covid-19 patients from Bhubaneswar were used for this study. We compared the NPS and saliva specimens collected from the patients within 48 hours of the onset of symptoms. The results of the saliva samples tallied with those of the NPS samples in each case,” said Pati.
Bhattacharya said the NPS sample collection technique causes discomfort to patients, besides forcing them to go to a swab collection center. “Saliva can easily be collected by patients themselves. The study indicates that saliva can be a good alternative diagnostic tool for the detection of SARS-CoV-2,” said the author.
If used, the alternative method can help the government reduce the cost of sample collection. Saliva collection will be a simple, easy, cost-effective, and time-efficient method of testing, said the scientists.
Salivary samples of 25 COVID-19 patients were analyzed by rRT-PCR. The following data were collected: age, sex, comorbidities, drugs. Lactate dehydrogenase (LDH) and ultrasensitive reactive C protein (usRCP) values were registered on the same day when a salivary swab was collected. Prevalence of positivity in saliva and association between clinical data and the cycle threshold as a semi-quantitative indicator of viral load was considered. Saliva was found to be 91% (CI 80-99%) sensitivity for saliva tests and 98% (CI 89-100%) sensitivity for nasopharyngeal swab (NPS) tests in previously confirmed COVID-19 patients, with moderate heterogeneity among the studies.
The paper is published titled: Saliva as a Candidate for COVID-19 Diagnostic Testing: A Meta-Analysis; PMCID: PMC7438940; PMID: 32903849