The rise in coronavirus cases and the long lines at health centers, IMSS clinics, shopping malls and Covid kiosks to carry out diagnostic tests have motivated the population to seek these supplies in laboratories, private hospitals, pharmacies and even on social networks.
One of the most demanded products is the antigen test which is sold in pharmacy of all country.
The antigen test allows to identify a protein known as “S” or spike of the SARS-CoV-2 virus, the results are obtained in 15 to 30 minutes.
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Faced with the demand, the secretary of Coahuila, Roberto Bernals Gómez, said that the Covid-19 antigen tests are good. “They are good, they cost 200 pesos and let me guarantee them, they are approved by international authorities,” he said.
What does the WHO say about rapid antigen tests?
In this regard, the WHO has published since 2018 an annual List of essential diagnostic tests that includes the recommended in vitro diagnostic tests that should be available at points of care and in laboratories in all countries.
The latest edition, published a year ago, includes the COVID-19 diagnostic tests recommended by the WHO (PCR test and antigen test).
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In Mexico, Profeco assures that “The positive result of an antigen test is considered accurate when the instructions are followed carefully, but there is more possibility of having a false negative, which means that it is possible to be infected with the virus, but have a positive result. “.
According to the Secretary of Health, SARS-CoV-2 antigen detection tests are useful for detecting specific molecules of the virus, which are present when there is an active infection, that is, when the person is sick at that time. moment.
These tests can be performed directly at the point of care for sick people, such as in doctor’s offices, health centers, service kiosks, among others. These tests are useful in communities with difficult access to a laboratory, and are recommended by the World Health Organization to complement the epidemiological surveillance strategies of the SARS-CoV-2 virus epidemic.
The positive result of an antigen test can be used to confirm COVID-19, in people who meet the requirements described above and does not replace the usefulness and use of molecular tests (RT-PCR).
Covid-19 home tests running out
These types of tests are sold in pharmacies, such as Savings, and cost approximately 200 pesos. However, they are currently out of stock.
In addition, antibody tests are also sold for approximately 320 pesos, although they are also sold out.
The antibody test, unlike the previous ones, is used to detect if a person has been infected by the virus and has developed defenses, and if the infection is still active or not. The presence of IgM immunoglobulins (which appear between 7 and 10 days after contact with the virus) and IgG (which appear between 10 and 15 days later) are analyzed.
A positive IgM indicates an active infection, while a positive IgG means the infection is gone. Although it is not used as a definitive diagnosis, it is useful to know if you have been in contact with the virus or to see the evolution of the disease in a confirmed case.