Diagnosis of Corona Virus (COVID 19)
As COVID-19 continues to be an existential threat worldwide despite adopting strict strategies to tackle it, it’s time we implement effective methodical measures and protocols to break the transmission chain and get back to a corona-free world.
The early diagnosis which is rapid and accurate is the first step in managing the spread and the containment of the pandemic. In the context of even vaccinated individuals getting infected and also an increase in the number of asymptomatic carriers of the virus, diagnostic testing, and early detection is the only preventive measure to stop the infectious spread between people and communities.
Earlier only symptomatic individuals or those who had contact with infected individuals were the ones to get tested. But as the government geared up the rules and regulations and imposed a virus screening test for even state-to-state travel, let’s get into details of the diagnosis of coronavirus.
The most commonly used diagnostic tests are RAT and RT-PCR. RAT or Rapid Antigen test detects viral antigen which is basically a protein present on the surface of the virus. It is called rapid because it gives result within 15-30 minutes.
RT-PCR or Reverse transcriptase Polymerase Chain Reaction detects viral RNA. It’s the most reliable and accurate test, thus considered as the gold standard diagnostic method. It has improved sensitivity and specificity as compared to any other diagnostic method. But it takes 4-6 hours to confirm the results.
Accurate diagnosis is possible only with proper specimen collection. For both these tests, specimens are collected from the upper respiratory tract using oropharyngeal or nasopharyngeal swabs as Coronavirus is transmitted through respiratory secretions which can infect any system in the body. When comparing both nasal and oral swabs, studies have shown that nasal swabs have a high positivity rate making it the specimen of choice. Also, the time of collection plays a crucial role. Once the virus enters a human body, it can be detected from day 2-14 as this time period shows a high viral load. Specimens collected before or after may not give accurate results. Other specimens include sputum if the patient has a cough, faeces if the patient’s symptoms include diarrhoea and can be detected in the blood.
RAT and RT-PCR are tests that tell us active infection i.e., whether a person is currently infected with a virus or not. RT-PCR allows amplification of small amounts of RNA present in the specimen, as it is a type of NAAT (Nucleic acid amplification test), thus facilitating precise detection. That’s why sometimes it is advised to go for RT-PCR even if the RAT results are negative.
In Serology, blood samples are collected to detect the presence of antibodies which are basically responses of the human body against the viral antigens or against the toxins produced by the virus. But as the body takes time to form a response, this test is generally used to detect past infections. It helps us to have an idea of the production of antibodies in our body which makes us immune to the infection.
Experts believe that Testing, Tracking, and Tracing can significantly help us to fasten the depletion of coronavirus along with social distancing, frequent handwashing, double masking, and complete vaccination.
As we are aware of the role of asymptomatic carriers in the progression of the pandemic, diagnostic testing and ruling out suspicion remains a wise decision. Let’s all fight together against this global health crisis and successfully reach the zero positive case status as soon as possible.