A virology lab in Vijayawada, the seat of power in Andhra Pradesh and now, a major COVID-19 hotspot, has gone for a makeover. The men and machine are the same but the spirit and kit have changed. The technicians and the staff at the lab can no longer test HIV samples in a casual manner. They are busy getting used to wearing additional protective gear while the ‘Abbott’ machine has been modified to take on a new role of identifying the novel coronavirus. This is one of the two virology labs, under AP State Aids Control Society, which has been converted to COVID-19 labs, adding to the long list of testing spaces that have cropped up in the last one month.
The state, which started off with zero labs in the initial days of COVID-19, has exponentially increased its testing capacity and capabilities. Andhra Pradesh, in a span of two months, has reached a peak of testing 8,000 samples per day, leaving other states behind in testing-per-million category. According to state health officials, they are aggressively looking to further ramp up the testing. Currently, the state is following more than half a dozen types of tests for COVID-19 suspects as well as those in the high-risk category. With a mix of machines from China, South Korea and also those used for detecting other diseases, the state is screening and testing people across the 13 districts of the state.
On a daily basis, a majority of tests in the state take place at the nine Virus Research and Diagnostic Labs (VRDLs), where the samples are tested by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). This antigen test is considered to be the most accurate and reliable, globally, to study novel coronavirus. The ICMR had backed these tests for primary testing as well as for confirmatory. The procedure is to take the nasal or throat swabs of the suspects. The material is treated in a laboratory setup to extract only the RNA and then it is converted to DNA after which it is amplified to detect the presence of the virus. The results may take anywhere between a few hours to half a day or more. Recently, the state got the approval to use two more VRDLs.
But, the game-changer for AP has been the TrueNat machines, primarily used to detect Tuberculosis (TB). These machines gave the edge to the state in scaling up testing quickly. Much before COVID-19 struck the state, there were around 250 TrueNat machines in health centres across the state. AP had the highest number of these machines when compared to other states. These were used to test for TB until ICMR cleared it to be used for COVID-19 detection. This is also an antigen test that works on the principle of Polymerase Chain Reaction (PCR). According to health officials, they were the first in the country to use TrueNat for testing samples for COVID-19. Though the machine remains the same, it has to be equipped with COVID-19 testing kits, which are already being manufactured in MediTech zone in Vizag. There are currently 45 labs where TrueNat machines are used for testing. The results usually take less than an hour. If the nasal or throat sample detects the presence of virus, then a confirmatory RT-PCR test is mandatory at one of the VRDLs.
At a recent press meet, Special Chief Secretary for Health, Jawahar Reddy, said that another test used for TB detection will help the state in the fight against COVID-19. The CBNAAT (Cartridge Based Nucleic Acid Amplification Test) machines were part of the TB control programme. There are five labs with the machines and the officials are gearing up to use them. The CBNAAT follows PCR method and can also be used as a confirmatory test. According to sources in the health department, the COVID kits to be used in the CBNAAT have been procured from Goa.
At the two virology labs, Visakhapatnam and Vijaywada, that were used for HIV tests, the technical modifications are almost complete. The ‘Abbott’ machines use RT-PCR method and are highly advanced and require no confirmatory test from outside the lab. In a 24-hour span, 270 samples can be tested in each lab. According to the technicians of the lab, minor changes are being made to facilitate swab samples instead of blood samples and by installing newer software for COVID-19.
The testing strategy of AP would be incomplete without rapid tests. The state was one of the first to place an order of more than one lakh kits from a company in South Korea. The state received the consignment almost a fortnight back. Unlike the rest, these kits are used to detect antibodies by drawing and testing blood samples of individuals. These kits have been deployed mostly in and around the red zones. These kits will only reveal if the sample has the presence of antibodies that have been produced as a result of a face-off with the COVID-19 virus. The result is out in less than 15 minutes. In the case of the presence of anti-bodies related to the virus, the individual’s sample is sent for RT-PCR test for confirmation.
However, the state is banking more on another form of antibody test, Chemiluminescence Immunoassay (CLIA). It is a highly sophisticated test which gives a clear picture on the extent of the antibodies present and not just its mere presence—2 ML of blood serum is required for the machine to analyse and give the result. In one hour, 50 samples can be tested. According to the state government officials, five CLIA machines, again for the first time in the country, have been imported from China. These machines are mostly used for thyroid profile and Hormonal assays. The only flip side of the machines is its pre-test and post-test calibration which takes a couple of hours. Confirmatory RT-PCR is a must if the samples detect higher count of immunoglobins.
The state government had also received 19,000 Chinese antibody rapid kits from the Centre. They were partially used near containment zones until the Centre ordered the state to discontinue using these kits.
That apart, the state is also pooling samples, numbering anywhere between two and seven, of individuals and testing through RT-PCR method to save up on regents. If any batch returns positive results then every individual is tested again to detect the virus.
“There are a few more type of testing methods that are in the pipeline and we are awaiting permissions’” informed an official.
For now, the state wants to increase the testing capacity to 10,000 to 15,000 samples a day. Unlike many states, AP is also testing asymptomatic people who reside close to containment zones.
