The Dubai Health Authority (DHA) has banned the use of rapid viral tests for Covid-19 due to the inaccuracies in the results of the tests. The test is said to give false negative and positive results for Covid-19 and has just a 30 per cent accuracy rate, studies have shown.
In a circular issued to all licensed private hospitals, outpatient care facilities and pharmaceutical establishments in Dubai, the DHA requested them to refrain from using or selling rapid laboratory screening kits to detect blood antibodies to the Covid-19 virus.
It stated: "This method (rapid viral test) has not yet been proven to be feasible and has not been universally adopted as a reliable diagnostic method. The DHA is continuously testing the effectiveness of these devices and will inform you in the event of any change in this matter."
Explaining how the rapid viral test is done and the reason for its inaccuracy, Dr Ahmed Abdelhameed, specialist internal medicine at Medcare Women and Children Hospital, said: "The rapid test is done by using blood samples of a person to detect blood antibodies formed by the body against Covid-19. It is not a direct detection of the virus but a kind of detection of the consequence of the virus once you catch the infection, and the body then starts forming antibodies to fight the virus. Therefore, this test cannot help in early diagnosis of the disease."
He added that although the FDA gave the emergency authority to use the test, the disadvantage of this test is that it is not accurate and its results and efficacy are still under question. "This is because for the body to form antibodies against the virus it takes days or sometimes even weeks. So this will delay in knowing if the patient is Covid-19 positive or negative."
Talking about the loopholes in the rapid viral test, Dr Ahmed said: "Sometimes antibodies are formed in the body because of previous infection of other strains of coronavirus that are not necessarily Covid-19. And this may give you appositive result for the virus, which may not be Covid-19. To avoid this confusion, the DHA has banned the use of the test as it can give you a false negative or positive result for Covid-19.
Elaborating on the current and the most effective process of doing the Covid-19 test, Dr Ahmed said: "We now use the polymerise chain reaction (PCR) test that detects the presence of an antigen (a toxin or foreign substance), rather than the presence of the body's immune response, or antibodies. By detecting this in this foreign strain in the body before antibodies form or symptoms of the disease develop, the tests can tell whether or not someone has the virus very early on. And this is done by simply taking the nasopharyngeal swab. The test results, depending on the number of samples a lab receives, take not more than four days. Therefore, the DHA has taken the most appropriate and effective approach by following the best diagnostic measures," Dr Ahmed said.
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