There are currently three tests that allow you to obtain the Covid-19 green certification. The molecular saliva test (also used for monitoring the circulation of the SarsCoV2 virus in schools and other limited contexts) was added to the molcular and rapid antigenic swabs. However, the other salivary test, the rapid one, not recommended due to the insufficient level of precision, remains excluded.
Molecular test: “gold standard”
The main and most reliable diagnostic tool remains the nose oropharyngeal molecular swab which consists of an investigation capable of detecting the genome (RNA) of the SARS-Cov -2 virus in the biological sample. This test has a very high degree of sensitivity and specificity, i.e. it has a high ability to identify virus-positive individuals so that there are as few false positives as possible and an equally high ability to correctly identify those who do not have the disease. . The molecular test remains “the international gold standard for the diagnosis of COVID-19 in terms of sensitivity and specificity” confirmed the Ministry of Health in the circular “Update of the indications on the use of salivary tests for the detection of SARS infection- CoV2 “. The analysis can only be carried out in highly specialized laboratories, identified by the health authorities. The result of this buffer is obtained on average in three / six hours. The cost: 60 euro.
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Antigen test (rapid swab)
The rapid antigen test is based on the search, in respiratory samples, for viral proteins (antigens). The sample collection methods are completely similar to those of molecular tests (nasopharyngeal swab) but the sensitivity and specificity of this test are
be lower than those of the molecular test. This involves the possibility of false-negative results in the presence of low viral load, as well as the need to confirm positive results with a molecular swab. It is a useful tool especially for screening investigations and where indications for control actions are needed in a short time. THE response times are very short: approx 30/60 minutes. The test has a government-controlled price: 15 euro.
Molecular salivary tests
To update the framework of valid tests for the purpose of green certification was the circular of the Ministry of Health in which it is explained that recent scientific evidence on molecular salivary tests have identified sensitivity values between 77% and the 93%. Furthermore, some studies conducted in the school setting have reported a high agreement between the results obtained with salivary molecular tests and with molecular tests on nasopharyngeal and oropharyngeal samples. If the molecular saliva test is positive, it is not necessary to perform a confirmation test on the sample. Response times: 24/48 ore. The cost: 60 euro.
Limited use (for now) to a few categories
However, the use of molecular saliva tests requires a higher number of steps which involve longer times for the processing of the samples. Therefore, says the ministry, in order to avoid the overload of regional microbiology laboratories, and to ensure adequate resources to ensure the sustainability of this public health activity, molecular tests on salivary samples – at least in a first phase – could be considered an alternative option to gold / nasopharyngeal swabs exclusively in these contexts: