In a moment of profound uncertainty linked to Covid-19, football is no exception. Continue to discuss what happened first to Inter, then to Roma, and finally to Lazio. These are those players “blocked” by Uefa before international competitions, and then recovered for challenges of A league. The question is legitimate: how do you explain such a sudden change in the results arrived a few hours later? The professor. Roberto Verna, president of the World Association of Societies of Pathology and Laboratory Medicine (World Society of Laboratory Medicine Workers), spoke to our microphones to clarify the situation, more and more intricate with the passing of the days: “The problem is not the difference between the Uefa test and that of Serie A, it is only a question of the sensitivity of the method. If Serie A did the molecular test, like Uefa, it would have the same result”.
ANTIGENIC OR MOLECULAR TEST? – Two different methodologies, but what are the differences? The prof. Verna has explained: “Rapid antigen tests have advantages over molecular tests. Faster response, lower cost, simplicity of execution. But it is known that the sensitivity of antigenic tests is lower than that of molecular tests, currently considered the gold standard for the diagnosis. The diagnostic sensitivity appears lower in patients with low viral load, while sufficiently high in subjects with high viral load, or in the initial stages of infection, when the virus diffusion capacity is maximum “.
DIFFERENT RESULTS – “If Uefa implements the molecular test, this is certainly much more sensitive, able to find small quantities of viral sequences in the individual who may even be asymptomatic. The antigen test, which is normally done, is able to detect the Infectivity based on the large viral load present. Suppose I have been in contact with someone the day before yesterday and have a minimal viral load, I will not test positive on the antigen test while I will be positive on the molecular one. But even in this situation, I could in any case, I feel very well because maybe the virus does not replicate and I am not symptomatic. Others develop the virus more, and become symptomatic “.
SYMPTOMS AND CONTAGIOUSITY – “If a person tests negative on the antigen test, it is very likely that they are not infectious. If I came in contact with the virus the day before yesterday, and I do an antigen test today, I will test negative. Tomorrow I do a molecular test and that, since it is more sensitive and detects a much smaller amount of virus, maybe it gives me a positive result. However, I will remain asymptomatic anyway “.
THE TIMINGS – “The two tests assume different timing. Before doing the antigenic one it will be necessary to wait a few more days from contact with a positive. It is very likely that in the immediacy of an infection, the antigen test will be negative. While the molecular test, precisely by virtue of greater sensitivity, should be able to detect even a minimal amount of virus immediately “.
AMPLIFICATION AND FALSE POSITIVES – “The molecular test is based on the amplification technique. False positives? Just by acting through amplification, it can happen that I amplify something that is not necessarily the virus. It’s like it’s interference. And so the swab is positive, but it is actually positive for any other gene in the body. “
STILL POSITIVE? – The president of the WASPaLM he then clarified the situation regarding those who are asymptomatic but who, nevertheless, remain positive for a very long period of time: “These delay the elimination of the virus. We all have an immune system that defends us from infections, it has its own times. People who have remained positive for a long time but with no symptoms are precisely those with very low viral load, and therefore precisely because it remains poor the immune system itself takes longer to eliminate it “.
A RIGHT DECISION – “They are two different systems, each with its own value. They also differ in terms of cost. The molecular test costs a lot more, requires a much longer process. Serie A does well to do the antigen test, is the answer better in cases of continuous screening. Laboratories are overloaded and, in the need to have an immediate result, we tend to be a little faster “.
Posted on 2/11
© RESERVED REPRODUCTION – The reproduction, even partial, of the article is prohibited. Violators will be prosecuted according to the law.
Covid, alarm at Ajax: many positives even in the first team
FORMELLO – Lazio, recovery: head to Zenit, meanwhile Lulic improves …
BACK TO HOME PAGE
