Covid: the ‘super buffer’ arrives; experts explain how it works and why it is different from others
Here comes the ‘super buffer’They exist on the European market over 500 types of tampons, but now one is coming that can tell us something more than the classic ones we have used so far. In fact, for a few euros more you can buy a tampon Coiable to measure not only positivity, but also the scope of symptoms.
Coi is the abbreviation of “cut off index“, or threshold index.
This test does not work with traditional colored bars, but provides a numerical index: if the swab result is less than 1 it is considered negative. If it is above it is positive. The sample is identical to the other tests on the market, but the difference lies in the fact that the positive strip becomes fluorescent instead of being colored red. The analysis of the result cannot be done with the naked eye, but with a special machine capable of indicating the presence of the virus.
The result will then be presented as “higher than 100“, or other values depending on the scale used for that brand of test.
Coi really represents viral load and therefore the intensity of the virus? “In a very indirect and imprecise way”, he told the newspaper Republic, Vittorio Sambriprofessor of microbiology at the University of Bologna. “The amount of protein detected by the swab is not directly proportional to the intensity of the virus”, h aaggiunto.
Also, he explains Concetta Castillettihead of the virology unit of the Negrar hospital (Verona), “Coi tampon scale is arbitrarily assigned by manufacturers” e the values are chosen without any scientific criteria.
The severity of the disease is not necessarily linked to the intensity of the viral load, but is affected by a number of factors, such as the patient’s pre-existing health condition and there is no buffer that can predict COVID symptoms.
Coi tests are often referred to quantities or semi-quantitative by the sellers, as opposed to the antigenic classics that they are qualitative. A swab is quantitative if it measures the amount of virus present in sample analyzed, “but defining the quantitative Coi test is one forcing“, experts say.
In any case, a high value of the Coi test it is not the same to symptoms more severe. Viral load can only be measured with molecular buffersbut in general its usefulness is limited: they have been there since the beginning of the pandemic asymptomatic people con high viral load and people with low chargesbut symptomatology heavy.
A parity of tests and with withdrawal methods identicala person with higher value it will take more time to negativize.
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