Wednesday, October 20, 2021
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Wednesday, October 20, 2021
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Why Symptomatic Patients Tests Negative For Covid-19 ?

The high possibility of spread makes us sure that we might be infected with the virus if we have Covid related symptoms but sometimes even after getting tested we might still get a report telling “negative” for SARS-CoV-2 despite having symptoms. Hospitals are only giving medicines to those who have tested positive for the virus.

So, what one should do if he tests negative even after having the symptoms of the coronavirus.

In India two types of testing for Covid-19 has been approved — Real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR), the standard testing and the other Rapid Antigen Testing (RAT), which is a kind of screening test. Anybody who tests positive is set to have coronavirus in their body.

A “negative” report, especially hurled by RAT, doesn’t preclude Covid-19. On the off chance that there are symptoms for Covid-19, specialists say it is ideal to start treatment early. For asymptomatic people, a “negative” report by RT-PCR is considered cofirm decision out of Covid-19.

Both RT-PCR and RAT are performed to detect the same virus but as compared to RT-PCR tests RAT is considered less reliable and is mainly used for screening.

In testing a swab is used to collect a sample from the tissues of either the throat or the nostrils from a person who is being tested.

The swab containing tissues is immersed in a fluid chemical that keeps the SARS-CoV-2 alive and active. It is kept in a unique chamber for transportation to an pathological lab with bio-security level-2 (BSL-2), according to the rules by the World Health Organization (WHO).

An outcome by the RT-PCR test is viewed as reliable. A positive report implies the individual has contracted Covid-19 and a negative report shows the individual is free from Covid-19 during the time of his sample collection.

Although, in some cases the result can be “false negative” which means a person’s report can still show negative result despite his sample being positive.

So, in order to get a true and reliable report from the test it depends on many things which are as under:

– method of sample collection should be correct,
– quality of sample should be good,
-chemical in which sample is immersed should be in adequate quantity so that virus remains active,
-safe transport of the sample, and
-timely testing of the sample

If there is error in any of the steps mentioned above then the result might show “false negative”. The technicians need to be trained enough so that they don’t these errors may lead to wrong results.

A senior consultant in the intensive care department Dr Ajit Thakur at the Asian Institute of Medical Sciences, Faridabad said, “An ideal test done which detects all the patients has a sensitivity of 100 percent. Incidentally, the RT-PCR for SARS-CoV-2 has a sensitivity of around 66 per cent.”

“It means one-third of infected persons will be missed out while testing. Even high sensitivity RT PCR or other test CBNAAT is also not 100 per cent sensitive,” he said.

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