The rapid serological test with lancing device has a sensitivity comparable to that of the traditional quantitative test based on the Elisa method: this is indicated by the research published in the journal EBioMedicine (The Lancet group) conducted last May by the 'Mario Negri Institute of Bergamo and coordinated by Giuseppe Remuzzi.
The data also indicate that detecting positivity alone is not sufficient and that this data must be accompanied by that relating to the viral load, i.e. the quantity of virus particles detected in the sample.
A result, they note, is very important for containing the infection.
Funded by the Lombardy Region, Milan Serravalle, Milan Tangenziale and Brembo, the research was conducted using the test developed by the Swiss company Prima Lab, said the first author of the study, Luca Perico, and the results indicate that the test "is substantially comparable to the venous test as regards sensitivity and specificity.
This - observed Perico - makes it possible to consider the rapid 'lancing device' test as an extremely effective and valuable tool for identifying subjects who have come into contact with the virus within ten minutes ".
The researchers also note that most subjects positive for antibodies to the new coronavirus experienced symptoms in the first two weeks of March, but a subgroup reported symptoms attributable to the virus as early as early February 2020. There are also no significant differences in positivity. between males and females, while positive volunteers are on average a few years older than test negative volunteers.
Of the 38.5% of serological test positive subjects, only 23 volunteers (who had had symptoms in the weeks prior to collection) also tested positive for nasopharyngeal swab, which measures the presence of SarsCoV2 genetic material in the nose and throat.
"The analysis shows that these are cases with a very low viral load which suggests that there is probably no infectious capacity", observed Susanna Tomasoni, head of the gene therapy and cell reprogramming laboratory of the Mario Negri Institute.
"The data to be related to the situation in May - continues the researcher - suggest that qualifying the extent of the viral load, rather than reporting only a positivity per se, is important for optimizing the discharge criteria for infected subjects".
For Ariela Benigni, scientific secretary and research coordinator of 'Mario Negri', the results of this research have "important implications for the containment policies that our National Health Service will have to implement in the event of a second wave of viral infection. ".
The research also indicates that "it would be advisable for the viral load to be quantified for each positive swab, so as not to have a misleading epidemiological picture".
Conceived in May, the test was designed for the next phase of the pandemic and in particular for schools and "the results indicate that sensitivity and specificity are very similar and very high, over 90%," Benigni noted.
"This is a fact that" suggests that this test is an effective tool for obtaining fast results in 10 minutes ", without requiring the use of a laboratory.
