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We read more test data almost daily, in some cases what kind of test they did, and other times we just see the numbers.
Why do you need such proof?
In short, each one has a reason for being, each one is useful for a different reason.
Why is the PCR test the standard, the most accurate?
Through an enzymatic reaction, a viral inheritance, a sample of ribonucleic acid (RNA) from SARS-CoV-2, the Covid-19 pathogen, is amplified so that it is available in detectable quantities. The test is ideal in principle, as it is unbeatable in terms of all the parameters that can be considered when evaluating tests of a similar nature, that is, sensitivity and specificity (simplified, the ratio of false negatives to false positives).
If this is so clear, why is another proof needed?
Unfortunately, PCR requires a lot of labor, experience, and time, and it also costs a great deal of equipment and chemicals to perform. There is also the possibility of errors here, such as improper sampling, lack of patient cooperation, but most problems can arise during storage and transport of the sample: RNA is extremely sensitive to all external influences and even temperatures storage, so it can degrade, before it enters the PCR machine, which can result in a false negative result, even if it was not caused by the PCR error itself. Therefore, the main disadvantages of the test are time, cost and very limited availability. To counter them, the so-called rapid tests.
They also detect the components of the virus, but in a different way, generally based on the phenomenon of fluorescence. They are much faster, can be run on site, and require no special expertise to perform, just training. These tests, unlike PCR, can only reliably detect a certain amount of virus, but this is not necessarily a disadvantage. In daily practice, we are primarily interested in the clinically significant amount of virus, that is, whether the person is currently infected or contagious. For example, the Rapigen Biocredit test, manufactured in South Korea and used in Hungary, detects the presence of viral RNA with more than 90% sensitivity and almost 100% specificity, so the “safety” is likely to be misunderstood. 50-60% “in the Prime Minister’s announcement. Based on. Of course, this is only true if the sampling is done correctly and the patient has followed the requirements for a successful test, that is, they have not eaten or brushed their teeth before the test, etc. This is because rapid testing, like PCR, relies on a nasal sample.
Photo: Matthias Schrader / MTI
This brings us to the third type of test, which is none other than that
These are made by drawing blood and, unlike previous tests, they do not detect the components of the virus, but rather the antibody formed against them. It takes time to produce antibodies, so these tests are more likely to determine if we may have already contracted the infection or have developed protection against the virus. This will be crucial after the advent of vaccines, but it is still important to carry out such tests, especially due to the spread of plasma treatment, and it is also of epidemiological and public health importance.
(Cover image: A sample is taken from a man’s oral cavity at a designated coronavirus screening clinic at Mohács Hospital on May 12, 2020. Photo: Tamás Sóki / MTI)
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