• Covid, Ministry of Health circular on rapid antigen tests

  • Covid.

    Salivary test for babies, "reliable as a swab" from 'researching mothers'

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May 15, 2021 Free use of salivary tests for the diagnosis of Sars-Cov-2 infection. The yes from the Ministry of Health with a circular in which, however, it is suggested to use the saliva sample "if it is not possible to obtain oral and nasopharyngeal swabs". In addition, the circular emphasizes that saliva testing can be considered an option for the detection of infection "in asymptomatic individuals who are repeatedly screened for professional or other reasons, to increase the acceptability of repeat tests if they are subjected to screening of very elderly or disabled individuals or in case of a shortage of tampons ". This is because "the available studies indicate a variable diagnostic sensitivity of molecular tests on saliva samples, in relation to the collection technique:a higher sensitivity was found in the early morning posterior oropharyngeal saliva, while a lower sensitivity was observed with the 'general spitting' technique ". Furthermore," the sensitivity decreases after the first five days onset of symptoms ".



The circular, reiterating that the molecular test on nasopharyngeal and oropharyngeal sample represents the international gold standard for the diagnosis of COVID-19 in terms of sensitivity and specificity, indicates the obligation of traceability of all tests, including salivary ones, in information systems regional. The results of molecular tests on salivary samples, even if carried out by laboratories, structures and private professionals accredited by the Regions, must be included in the reference regional information system. "The use of saliva for the diagnosis of SARS-CoV-2 infection it involves a non-invasive method of collection, however the correct collection of the salivary sample is a crucial step.Saliva samples can be different: oral saliva, posterior oropharyngeal.Different techniques and collection sites can also have an impact on the sensitivity of the method "the circular reads. In addition, the saliva samples can be mucous and viscous, causing difficulties in processing with the methods and automated equipment of RNA extraction or existing extraction / amplification.



There are rapid antigen tests that have been validated in EU Member States on the basis of alternative samples, such as saliva, sputum and / or faeces, and it is questionable whether these tests should also be included in the list of rapid antigen tests agreed by the 'HSC. In addition, the sensitivity decreases after the first five days of the onset of symptoms. Overall, the available studies indicate a variable diagnostic sensitivity of molecular tests on saliva samples, in relation to the collection technique: a higher sensitivity was detected in the early morning posterior oropharyngeal saliva, while a lower sensitivity was observed with the technique. of "general spitting" or the collection of saliva accumulated at the level of the oral floor.