Considerations for the use of saliva as sample material for COVID-19 testing
This document outlines the use of saliva as a diagnostic sample for detecting SARS-CoV-2 infection, considering the advantages, limitations and uncertainties associated with the use of saliva as sample material.
- Nasopharyngeal specimens remain the gold standard for COVID-19 testing for use with RT-PCR and rapid antigen diagnostic tests.
- Studies on the performance of RT-PCR tests have variously reported both higher and lower sensitivity for saliva samples compared with nasopharyngeal swabs. However, meta-analyses of such studies suggest an overall similar or non-statistically significant lower sensitivity associated with the use of saliva samples.
- The reported heterogeneity is likely to, in part, reflect differences in sampling techniques, sampling times and the type of population being tested, with evidence that RT-PCR tests with saliva as sample material show similar sensitivity to those using nasopharyngeal swabs for symptomatic patients, if the sample collection is performed within the first five days from onset of symptoms, and when the viral load is high.
- Saliva sample collection is easy, non-invasive, more acceptable for repeat testing and can be performed by non-healthcare professionals or individuals themselves who are properly instructed.
- Evidence supports the conclusion that saliva can be used as an alternative sample material for RT-PCR testing when nasopharyngeal swabs cannot be collected in the following scenarios: in symptomatic patients and for repeated screening of asymptomatic individuals.
- Further clinical studies are warranted on the sensitivity of saliva as sample material for RT-PCR analysis for symptomatic and asymptomatic children, and to standardise the sampling collection methods.
- Current limited evidence does not support the use of saliva as an alternative sample material for rapid antigen or antibody tests. Further clinical validation studies on the different available tests are needed.
- Commercial diagnostic assays for saliva with a CE-marking are available in the European Union/European Economic Area (EU/EEA). None of these assays is included in the Health Security Committee list of mutually recognised tests.