NEW DELHI: An "exponential" ramping up of coronavirus testing is required to gauge the actual impact of the 21-day nation-wide lockdown, health experts said on Monday as India nears the final week of the unprecedented measure. The experts agreed that the lockdown has helped in slowing down spread of the virus but insisted that the situation has not reached a plateau and that there was an urgent need to upgrade healthcare facilities to deal with the crisis.Government officials involved in strategising India's approach to contain the pandemic said the overall social distancing model adopted by the country helped in checking spread of the virus compared to many developed countries including the US which reported 3,30,000 cases India went under a nation-wide lockdown from midnight of March 24 to combat the pandemic."Because of the lockdown and our efforts to promote social distancing, cases were being reported but there was no sharp rise," says Joint Secretary in the Health Ministry Lav Agarwal However, experts said India is still not out of the woods and large scale testing alone can make the overall picture clear."There is a need to scale up testing exponentially if we want the lockdown to work," says Ramanan Laxminarayan , Director and Fellow at the Center for Disease Dynamics , Economics and Policy.Arvind Kumar, renowned lung surgeon at Sir Ganga Ram Hospital, said India is into stage three of the coronavirus infection which is the community transmission stage."We are into stage three now. But stage three is a broad spectrum, so not just hundreds of thousands of cases constitute community transmission stage. There have been many cases reported with no travel history or contacts with affected people," he said.Asked to compare the growth of the cases in India vis-a-vis other countries like the US and Italy, Kumar said the comparison was not valid."I do not think there can be a comparison. In India, the cases and deaths are rising. We are on the ascending curve and that too in a lockdown. We have to be very careful," he said.Kumar also cautioned against completely lifting the restrictions, saying "if we relax the lockdown while cases are rising, it will be an explosion of cases.""The lockdown should only be lifted when the number of cases start dropping, which is not happening right now," he added.Laxminarayan favoured adopting the PCR (polymerase chain reaction) testing model, also known as pooled sampling to identify infected people in a population.The use of a pooled testing strategy could reduce the time, cost and resources required while identifying infected people in a population and estimating the infection rate, he said.This would allow identification of community clusters for targeted public health interventions, Laxminarayan said. Dr Navin Dang , founder Director of Dr Dangs Lab, said the entire purpose of the lockdown would be defeated if testing is not ramped up."As we are gradually seeing the cases increase, we need to ramp up our testing capacity by increasing the number of centres performing the real PCR tests both in the government and private sector without which the outcome of the lockdown cannot be determined," he said.India's apex medical research body ICMR has already issued guidelines to roll out a rapid antibody test to detect coronavirus infection. The test works on blood samples instead of nasal swabs."Overall testing for COVID-19 using real-time PCR is increasing and we will be approaching full capacity in near future. At the same time, we are expecting delivery of Rapid Test kits (blood based) for use in response to COVID-19 situation," ICMR DG Balram Bhargava said in a letter to health secretary Preeti Sudan few days back.The results of the antibody tests are available within15-30 minutes.The government's primary focus has been places from where a number of cases are being reported, large gatherings and evacuation centres.Another focus area for rapid testing is patients suffering from influenza like illness (ILI) with an objective to use it as a more effective monitoring tool in these areas."These will be our criteria for distributing the kits once we get the supply," Agarwal had said on Sunday.Dr K K Aggarwal, President of the Confederation of Medical Association of Asia and Oceania (CMAAO) and former IMA President, said the outcome of the lockdown would be determined by the testing."We need to intensify the testing so that those who are positive by now can be quarantined for another 14 days," he said.Kumar said more tests need to be conducted, and more and more isolation and containment strategies need to be worked out to contain the spread of the infection.Another expert, who did not wish to be named, said that the biggest problem is that health being a state subject, different states are following different advisories in terms of containment plan and testing strategies and this is creating confusion."It should be India without borders when it comes to dealing with such a calamity and uniform testing protocols should be implemented all across the country," the expert said.With the final week of the lockdown approaching, the government has come out with a containment plan as clusters posing high risk of further spread of COVID-19 cases have emerged in several states like Kerala, Maharashtra, Rajasthan, Uttar Pradesh, Punjab, Karnataka, Telangana as also Delhi and Ladakh.The cluster containment strategy would be to restrict the disease within a defined geographic area by early detection of cases, breaking the chain of transmission and thus preventing its spread to new areas.A health ministry official said India would be following a strategic approach in dealing with a variety of cases including travel-related cases, infection arising out of local transmission as well as for large-scale outbreak.India has reported a total of 4,067 positive cases of coronavirus and 106 deaths, according to the Union Health Ministry.A tally of figures reported by states directly showed at least 126 deaths across the country, while the confirmed cases reached 4,111.There has been a lag in the Union Health Ministry figures, compared to the numbers announced by different states, which officials attribute to procedural delays in assigning the cases to individual states.Globally, the virus has infected more than 1.27 million people and killed over 69,000.