covid test, why so many false negatives?


In recent times you must have heard about cases of people who do antigen test to detect covid and they come back negative, symptoms continue and two or three tests are repeated and it shows that they are positive.

contradictory test

There is one explanation for this, and this new strain of Omicron may show symptoms before it can be detected by a rapid test.


After infection, it is possible to spend up to four days with symptoms for tests to detect it, and this is because rapid antigen tests are positive when the viral load is high, which is also when the risk is greatest. Other people who can get infected.

Before the appearance of this type, the most reliable tests were: PCR and antigen; The latter, most popular for its accessibility, because it can be done at home and above all, because it gives results in 30 minutes; However, you may give wrong results with the newer version.


Antigen testing is a good tool for early detection of COVID cases, but by its very nature it can return false negatives.

These detectors are very sensitive and do not amplify the genetic material found in the nose or mouth, so they can register the virus from other types of diseases and not COVID-19, which is why they detect false infections. Come to diagnose.

This rapid test consists of two lines, one marked with the letter “C” which stands for control, and the other with the letter “T” which detects the viral load, but it appears to be only that the result is positive.


This is where the paradox arises, because a person who was tested for antigens at an earlier stage of infection and appeared to have the letter “C” can become a positive case in days.

Due to the number of false negatives of rapid tests, experts recommend that, if you have flu symptoms that are practically the same as those of covid, you should be isolated for as long as two or three days after symptoms appear. A new test is not performed. ,

There are theories that suggest that the relationship between the onset of symptoms and the peak of viral load has changed with micron.


For this reason, doctors recommend doing more than one test, or in the best cases, resorting to PCR, although they take longer because their results are obtained in three days, they are more accurate.

The number of SARS-CoV-2 infections is high, but it should also be remembered that the symptoms of this new strain are less severe and the number of hospitalizations is very low.

There are so many infections that experts speculate that this could be the beginning of the end of the pandemic and that Covid is already an endemic disease. It will not disappear, but, with vaccines and infections, it will become like the flu or influenza like many of the pre-existing forms. The good thing about this is that the death toll from Kovid will be very low, which is close to the figures for deaths from pneumonia, influenza or flu that we have.

On Monday, January 3 alone, the United States recorded a record high of more than a million cases in 24 hours, as Johns Hopkins University reports. It is estimated that microns represent 95.4 percent of infections in that country, the Centers for Disease Control and Prevention said.

Doctors at Massachusetts General Hospital recently met and estimated that the Omicron version has 100 percent presence in that city in the United States and is starting to take over the entire world.

He estimates that the delta version has almost completely disappeared. In addition, they believe that in February it will reach its peak of infection, but in March cases will begin to decrease, and in the future it will become a pediatric disease affecting more minors without immunity.

They explain that the micron lives primarily in your nose and upper respiratory area, which is what makes it so contagious, but it can’t be attached to your lungs like other types. For them, contact tracing has no value as we will all catch it, so they believe there is no need to stay at home and go to work or become a monk, unless you are immunocompromised or 85 years of age or older. K, but they recommend staying away from large gatherings for the next six weeks.

Micron is more contagious, but less deadly than the rest of the types, according to doctors and scientists, but the WHO stressed that it would be a serious mistake to classify it as a “mild” disease, as it is killing people. and lead to hospitalization. ,

But this does not mean that we should not vaccinate or respect sanitary measures, reassure doctors at Mass General Hospital, because the risk of infection can lead to complications, because of many factors that affect some young and healthy people. make weak, are still unknown. The hospital’s director of international infectious diseases points out a few points about what is included in the new version, including that almost 100 percent of positive cases in this hospital are caused by microns.

The Delta is almost entirely gone from New England. This growth will peak sometime between January 10 and January 21, then begin a rapid downhill journey of two to four weeks to end with a positivity rate of 20-50 percent.

For February 4th it will be cleaning mode and in March this year it will start coming back to “normal”. The increase in hospitalizations should be viewed with caution, as most of them are secondary admissions.

It is believed that a booster vaccine would not be needed for Omicron because it could not be developed before it was completely eradicated and that most of the population would suffer from it, giving the immunity needed to ward off the disease.

It may be that this type helps to vaccinate many people, even those who have not been vaccinated, but we cannot forget the fact that many people are not vaccinated. will be properly infected by people and millions of people in the world can die because of it. Lack of defense mechanism.

Experts tell us not to panic, but that we continue with the necessary hygiene measures, and that we return to our lives as normal as possible, but in these coming months they try to avoid mass meetings to avoid contagion. Huh.

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