Covid saliva tests, green light with limitations: when to use them

Here it comes Green light from the Ministry of Health for molecular saliva tests but with some limitations Because sensitivity decreases after symptoms appear in the first five days, and why “a saliva sample can be considered an option to detect SARS-CoV-2 infection if gold / nasopharyngeal swabs cannot be obtained.” This is what was expected in the new publication of the Ministry of Health, signed by the Director-General of Prevention, Gianni Reda, regarding the use of molecular and antigenic tests on saliva for professional use to diagnose SARS-CoV-2 infection.

“A saliva sample may be considered an option for screening for SARS-CoV-2 infection in asymptomatic individuals who are frequently tested for professional or other reasons, to increase acceptance of repeated tests, in particular: if individuals are very elderly or disabled Examine them and if there is a shortage of tampons, “confirms the circular indicating when to use the molecular saliva test.

In the publication on saliva tests, the Ministry’s technicians highlight how “The use of saliva to diagnose SARS-CoV-2 infection provides a non-invasive method for collection, but the correct collection of a saliva sample is a critical step. Saliva can be heterogeneous (oral saliva, Posterior pharyngeal saliva) and the different techniques and sites of collection can have an effect on the sensitivity of the method. In addition, saliva samples can be mucous and sticky, which causes difficulties in processing with existing automated methods and equipment for RNA extraction or extraction / amplification. ”

Moreover, “saliva has been assessed as a potential substrate for antigen tests based on automated laboratory instrumentation, with a chemiluminescence reading – generalization concludes – for the time being, the available stock of tests labeled Ce-Ivd for salivary matrix is ​​limited, but is being expanded. Comparison indicates. With the molecular test, the sensitivity is similar to that observed in the nasopharyngeal swab for saliva. ”

One such test can be molecular saliva tests A useful tool for monitoring and controlling SARS-CoV-2 infection in a school setting. And some studies published in 2020 found that the sensitivity between 53 and 73% “confirms the new circular of the Ministry of Health.