Tirupati: Now, Covid confirmatory test through TrueNat machine

Tirupati: As the coronavirus is spreading fast amid reports that there would be a manifold increase in these cases in the days to come, there is a need to test more samples.

Already, Andhra Pradesh tops the States in the country in terms of number of tests being conducted as it crossed four lakh tests by Thursday out of which 4,112 tested positive. Though RT-PCR test is considered ultimate in deciding the positive cases, almost for the past two months tests are also being held through TrueNat machines which are primarily used for TB screening. The advantage of these machines is that it gives result much earlier than RT-PCR.

However, the problem is that the samples tested positive in TrueNat machines need to be confirmed by RT-PCR which is final. To avoid this delay, ICMR has given its nod to conduct confirmed tests also through TrueNat machines. Accordingly two genes should test positive before the patient is declared positive for Covid-19. Chittoor district TB Control Officer Dr B Ramesh Babu has said that E-gene will be tested through TrueNat initially. If it gives positive result, the sample of that patient need to be tested through RT-PCR till now. Now, using separate kit RdRP gene will be tested again in TrueNat.

If that is also positive, the patient is Covid-19 positive. In case, if gene-E gives positive and RdRP gives negative result, it would be considered as presumptive positive and the patient will be sent back. That patient will be tested again after 10 days for confirmation.

Dr Ramesh Babu added that, the advantage of this RdRP gene testing is that it greatly reduces the waiting time for result. In 40 minutes E-gene result will be out and if it is positive, then in another 20 minutes RdRP testing will be completed to declare any patient is positive or presumptive positive.

To a question, he said that RdRP gene testing was being done from June 2 and so far 9 positives have come up through this process. Using TrueNat machines 15,150 tests were held in Chittoor district till June 4 out of which 14,217 were negative. There are 21 machines here and 10 new machines are expected soon.