the new Ministry circular

The Director of Prevention of the Ministry of Health, Gianni Rezza, has signed in the past few hours the circular recognizing the validity of test antigenici latest generation rapid in case definition Covid-19, in light of the new European indications, also giving a more precise definition of “positive” to the new Coronavirus. The text, entitled “Update of the Covid-19 case definition and testing strategies”, provides for the obligation to traceability of all the tests in the regional information systems: “The results of rapid antigen tests or RT-PCR tests, even if carried out by laboratories, structures and private professionals accredited by the Regions – it says – must be included in the reference regional information system” . But let’s proceed in order.

Definition of positive in the ministerial circular

First of all, the ministry’s circular specifies the definition of a positive case in Covid-19, come on clinical criteria (presence of at least one of the following symptoms: cough, fever, dyspnoea, acute onset of anosmia, ageusia or dysgeusia, but also headache, chills, myalgia, asthenia, vomiting and / or diarrhea), to those radiological, going through the criteria epidemiological (that is to say if you have been in direct contact with an infected person in the 14 days prior to the manifestation of symptoms or in health contexts (hospital and territorial) and socio-assistance / social-health care such as RSA, long-term care, closed or semi-closed communities) laboratory. Precisely in this case, it is specified in the text, reference can be made either to the “detection of SARS-CoV-2 nucleic acid in a clinical sample, or to the detection of SARS-CoV-2 antigen in a clinical sample in contexts and times defined in the dedicated section: Use of rapid antigen tests “. Three types of cases can be reported: possible (a person who meets the clinical criteria); likely (a person who meets the clinical criteria with an epidemiological link or who meets the radiological criteria); confirmed (A person meeting the laboratory criterion). Therefore, the circular specifies that “for the purposes of national Covid-19 surveillance (both individual case flows coordinated by the ISS and the aggregate one, coordinated by the Ministry of Health), only cases classified as confirmed according to the new definition must be reported.”

Rapid tests valid as swabs

The most significant novelty of the new ministerial circular concerns antigenic tests, which become valid for the statistical calculation of cases of Coronavirus positivity like molecular swabs. The text, however, recommends the use of rapid antigen tests with minimum performance requirements: 80% sensitivity and 97% specificity. These antigenic tests, it is noted, appear to show “superimposable” results to the Rt-Pcr assays (molecular tests), especially if used within the first week of infection, and on the basis of the data available at the moment, they appear to be “a valid alternative to Rt-Pcr. In the case of asymptomatic or mild symptoms, the molecular ones – confirmed by the ministry – remain the gold standard, which is the most efficient tool for confirming Covid-19.

When and for whom to use antigenic products

If the patient’s clinical conditions show discrepancies with the latest generation test, the Rt-Pcr remains the gold standard for the confirmation of Covid-19 “. In the event that a quick response is needed or if it is necessary to take public health measures extremely quickly, notes the circular, “the use of rapid antigen tests in individuals with compatible symptoms with Covid-19 in the following contexts: high prevalence situations, to test possible / probable cases; outbreaks confirmed through Rt-Pcr, to test symptomatic contacts, facilitate early detection of further cases as part of contact tracing and outbreak investigation; community closed (prisons, reception centers, etc.) and workplaces to test symptomatic people when a case with Rt-Pcr has already been confirmed; in health and socio-welfare / social-health contexts, or for the triage of symptomatic patients / residents at the time of access to the facility or for early diagnosis in symptomatic operators “.

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