News By/Courtesy: Gunjan Dayal | 27 Jun 2020 21:29pm IST

HIGHLIGHTS

  • Dr. P. Srinivasan, technical director at Neuberg Diagnostics and Chairman & Co-Founder of Be The Cure Registry and Jeenomics.
  • Antibody tests can be useful at this point in a population if they want to see what proportion of the population is affected for epidemiologic reasons.
  • If someone needs to test, then they need to have symptoms.

Dr. P. Srinivasan, technical director at Neuberg Diagnostics and Chairman & Co-Founder of Be The Cure Registry and Jeenomics (Next Generation Sequencing HLA Laboratory) of Jeevan Stem Cell Foundation, Chennai, spoke to G. Ananthakrishnan on current testing options for the novel coronavirus SARS-CoV-2, when to think of taking the test, state of antibody testing. Several questions were asked to him, some out of which were, what is happening currently with COVID-19 testing in Chennai and other places? He said that “Testing goes on. I am involved with Neuberg [Diagnostic laboratories] and we do on average about 200 tests a day. It is RT-PCR [Reverse Transcriptase-Polymerase Chain Reaction] which is the gold standard. Three different things have been floating around. We heard a lot of noise about the antibody test. Recently there is talk on the antigen test. RT-PCR will remain the gold standard for all viral infections. Even [with] RT-PCR one needs to understand... can it give a negative report when someone has the infection? The answer is yes. One reason is when the test is done too early when there is no viral material in the swab, and two, when the swab is not properly taken.” Another question was, now that we have crossed three months into the infection, what is the state of antibody tests using ELISA or other methods? For which he said, “It all started with rapid testing [for antibodies], and any rapid test for any disease has its limitations. The same thing happened with HIV when it started. Now, of course, far more rugged, reliable rapid tests are available, but it took ten years. The antibody tests for COVID are like infection, you have an IgM and IgG, the M arrives around seven days or so after picking up the infection. The G appears a little later and remains longer”. The antibody kits available right now are all mainly IgG, almost all of them, so it's a complete package for both M and G. There's no point in diagnosing the illness with this. They are looking to pick up active-illness patients. It doesn't make sense to test an IgG. But the antibody tests can be useful at this point in a population if they want to see what proportion of the population is affected for epidemiologic reasons. The antigen test-we are simply looking at viral RNA in a PCR and in the antigen test, what we call antigen is once again viral protein. Whatever technology they use, that takes hold of it. But if you read the antigen test information, if it says positive, you can be 100 percent sure it is positive. Unless the result is negative, however, then they need to follow it up with PCR. Since the negative result is not effective on an antigen-based assay. So if they look at sensitivity, it's 50% to 80%, and though there's an infection, there's a 50 % chance that the antigen test will be negative. And if those people are walking on the highways, they are infecting others. He didn't think the antigen test at this stage is appropriate for monitoring people for an infection until the sensitivity increases. Another question was, why is it difficult to make our tests and not import? He said, “It is not difficult. A few companies have made them. Any start-up has its problems and issues of sensitivity and specificity. Probably it will take another 100 days to provide the number of tests we are looking for. COVID has demonstrated something phenomenally good in health care. When pushed to the corner, we are capable of coming up with the best that is possible, at a cost that others cannot think of. On PCR kits, it will take some more time, it will happen, possibly in another 30 or 40 days”. At last, he said that those who have antibodies from infection, there is the view that they may be better placed to resume activity, the ICMR study shows that he thinks it to be some 0.83% of the population that tested positive for IgG. That essentially means the majority of India is not infected. The bottom line is that if someone needs to test, then they need to have symptoms. Wait three to four days with symptoms before the test. If people will rush, they may get a negative result.

THIS ARTICLE DOES NOT INTEND TO HURT THE SENTIMENTS OF ANY INDIVIDUAL, COMMUNITY, SECT, OR RELIGION ETCETERA. THIS ARTICLE IS BASED PURELY ON THE AUTHOR'S PERSONAL VIEWS AND OPINIONS IN THE EXERCISE OF THE FUNDAMENTAL RIGHT GUARANTEED UNDER ARTICLE 19(1)(A) AND OTHER RELATED LAWS BEING FORCE IN INDIA, FOR THE TIME BEING.

Section Editor: Pushpit Singh | 28 Jun 2020 10:21am IST


Tags : #InsightIntoCoronavirus

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