Mohamed Ibrahim Bassyouni
2020 / 7 / 29
PCR analysis is a technique that allows the creation of millions of DNA replicas from a single sample, to amplify the acid, allowing doctors to discover how the body suffers from various diseases and viruses. Analysis can detect viruses because it -convert-s DNA into nanoparticles, which helps the emergence of diseases, unlike normal detection, which is superficial versus analysis.
Since the early 1980s, PCR technology has emerged and is being used extensively in a number of laboratories for paternity testing and for criminal investigations.
PCR was also used to detect cancers, such as leukemia and lymphoma before the disease was able to from the body, in addition to discovering malignant cells, infections, bacteria and viruses.
The doctor requests this test for several reasons, including the detection and identification of pathogens precisely before they appear clearly in the body, and the most common things that PCR is requested for are: Corona virus, HIV and other viruses and some fungi.
In the first corona pandemic, there were errors in the method of taking the swab sample, but now the human greening is unjustified. False positive PCR examination is rare. It means that a person’s result is positive (that is, the PCR picks up the virus’s RNA) while it is not HIV-positive. When a positive test comes, its accuracy is 95%, which is an excellent percentage. False negative examination is more common, which is when a person is ill, but his examination is negative. There are several reasons: the insufficient amount of virus withdrawn during the nasal swab´-or-the timing of the examination (very early´-or-very late in the disease). The percentage of negative passive occurrence is about 30%, which is not small. When it happens as is happening now, i.e. people whose tests were positive and then returned negative, there is a greater possibility that what happened is negative negative in the second time than positive false wrong the first time (as a result of a problem in the swab, the amount of the virus that becomes less in the upper airways, for example ...). However, there is still the possibility of the wrongly positive posing as a technical problem. The tests used are not the same in all countries. I do not know which examination to rely on in Egypt, but there are better tests than others, especially in terms of the primers used.
On the other hand, a hospital in France faced this problem a month ago, while several cases were discovered in a city, after which it turned out to be false positives. The problem was one of the materials used for the examination, which was invalid, not in terms of duration, but when it was changed, the results of the tests returned intact. Such problems may occur, sometimes some of the materials are not valid for a manufacturing error,´-or-in the preservation,´-or-expired, in addition to problems that may occur in the PCR device,´-or-of course in the same protocol in terms of choosing primers´-or-choosing temperatures and reaction times.
In any case, the reason must be determined quickly, because the loss of confidence in the result of the examinations and the variation in the results from one hospital to another will result in more chaos than the existing chaos. Instead of re-examining every two days, the positive and even negative attendant should be isolated for a sufficient period (not less than 10 days) before the re-examination.
Can some medications cause wrong results in PCR analysis?
Sometimes this happens, because PCR analysis focuses on blood and proteins and is therefore easily affected by the effect of some medications taken by the person being analyzed to detect viruses but does not affect when paternity is discovered, so it sometimes requires not to get medication before undergoing the analysis in order to know the diseases.