WHO Opinion and PCR Test
Back in early March 2020, the head of the World Health Organization, Tedros
The document states that so far this is the most accurate and reliable diagnostic method, which allows even a small amount of SARS-CoV-2 RNA to be detected in human blood.
The first tests for coronavirus by PCR weredeveloped at Charite in Berlin in January 2020 using real-time reverse transcription polymerase chain reaction (rRT-PCR). It was these tests that became the main for the millions of tests that WHO distributed to search for patients with coronavirus infection.
A similar method of searching for coronavirus is usedthe South Korean company Kogenebiotech, which in its PCR-based tests allows you to find the “E” gene, common to all beta-coronaviruses, and the RdRp gene, specific to SARS-CoV-2.
US Centers for Disease Control and PreventionDisease distributes the RT-PCR diagnostic panel to public health laboratories through the International Reagent Resource. One of the three genetic tests in the older versions of the test suites yielded inconclusive results; many experts attribute the current development of the US pandemic to the fact that the initial tests did a poor job of finding the RNA of the virus in human blood.
Only March 13, 2020 an American companyRoche Diagnostics has received FDA approval for a test that can be run within 3.5 hours, allowing one machine to complete approximately 4,128 tests in 24 hours and dramatically increase the number of coronavirus tests in the United States.
Number of coronavirus tests performed by country
- USA - 8.3 million tests, or 25 thousand tests per 1 million population
- Russia - 4.98 million tests, or 34.1 thousand tests per 1 million people
- Germany - 2.7 million tests, or 32.8 thousand tests per 1 million people
- Italy - 2.3 million tests, or 39.3 thousand tests per 1 million population
- Spain - 1.9 million tests, or 41 thousand tests per 1 million population
- Great Britain - 1.53 million tests, or 22 thousand tests for 1 million people
- India - 1.4 million tests, or 1 thousand tests per 1 million population
- France - 1.3 million tests, or 21 thousand tests per 1 million people.
How does the PCR test work?
To carry out physiological testsFrom the patient's fluids - in the case of coronavirus, this is a swab from the oropharynx or nasopharynx - single-stranded RNA is extracted, double-stranded DNA is modeled on its basis and duplicated many times using a special enzyme (polymerase). Increasing the number of copies of DNA is called amplification. As a result, the concentration of certain DNA/RNA fragments in a biological sample, initially minimal, increases significantly.
In Russia, almost all the tests that are donein the 15 largest diagnostic laboratories of the country, including paid ones, such as Helix, they are produced by the Novosibirsk Center for Virology and Biotechnology Vektor.
EMG Tests
On March 20, Roszdravnadzor gave permission forthe use of a Russian-Japanese diagnostic system for detecting coronavirus, which was brought to the Russian market by the company Evotek-Mirai Genomics (EMG). Russian-Japanese technology for rapid diagnosis of COVID-19 is a joint development of the Japanese company Mirai Genomics and its Russian partner Genetic Technologies, which consists of tests and portable diagnostic systems.
Technology enables high precisionrapid diagnosis of the virus in 30 minutes. Due to the fact that the technology is adapted for mobile laboratories, it allows you to test people anywhere and can process samples of 20 people at once.
Now this system most oftenuses Yandex to conduct its own testing for coronavirus in Moscow. The tests themselves, like many reagents, are produced in Russia. It is planned that the price of EMG tests will be on average five times less than standard PCR tests in Europe.
The key difference between EMG tests and PCR is that theyconduct ELISA (enzyme-linked immunosorbent assay). This technology determines the antibodies that the body begins to produce no earlier than a week after infection - the so-called early antibodies, later ones are replaced. At the same time, the EMG test allows you to determine the presence of the virus already at the very early stages, while other coronovirus diagnostic systems are less sensitive and cannot detect the virus at an early stage of infection.
Antibody test
Coronavirus antibody test allows you to find outwhether a person has had COVID-19 and whether they have special proteins in their body that fought this virus and, hypothetically, will be able to resist it in the future. We talked about this analysis in detail here.
Antibodies to coronavirus can be tested andin Russia, but mass testing is carried out only for doctors using the test system of the Novosibirsk “Vector”. Also on a small scale, the Israeli clinic Hadassah Medical in Skolkovo is engaged in such studies.
In late April, it became known that fivelarge networks of medical laboratories will begin mass testing of Russians for antibodies to coronavirus: Helix, INVITRO, Gemotest, KDL and LabQuest. They plan to detect antibodies: early - IgM and late - IgG, which replace the early ones with a primary immune response to an antigen unknown to the body.
However, while on the sites of these clinics are invited to take a test for coronavirus. In the future, their price will be from 900 to 4,000 rubles, depending on the region.
New Coronavirus Tests
At least 10 are currently being developed in Russiaexperimental testing systems for COVID-19, and around the world - at least several hundred. For example, the FDA recently approved the first coronavirus test using CRISPR technology. Its results become known within an hour.
Northwestern recently released a patch-shaped sensor that can detect potential coronavirus infections in the early stages.
At the same time, pass a PCR analysis without symptomsalmost meaningless, because the virus is looked for in the epithelial cells from the nasopharynx, and the absence of symptoms means that it has not yet affected the nasal and throat mucosa. At the same time, the virus can be in the cells and simply can not reach the mucosa. Therefore, with a negative analysis, the test is usually sent for verification and repeated.
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