THIRUVANANTHAPURAM/KOCHI: Kerala chief minister Pinarayi Vijayan announced on Saturday evening that the state will go in for "rapid testing" to help gauge more quickly and effectively the extent of the virus’s spread within threatened communities. Rapid testing will involve a blood sample instead of a swab and results will be known in 45 minutes to 2 hours.It will help screen more people in a mass way on a daily basis and is much cheaper than the present RT-PCR testing method. Moreover, it can be repeated when a patient is in isolation/quarantine to check IgG AB levels, which can reveal the extent of recovery.The test will initially be confined to districts which have the highest number of positive cases and where a large number of people, who were carriers of the virus, returned from abroad. Sources said Kasaragod (with an astounding 77 positive cases), Kannur and Kozhikode districts will be initially tested.Though one of the advantages of the rapid test is that it will show a "positive" result even if the person is in the incubation period, health authorities warned that it cannot be deemed final. Hence, positive cases will have to be reconfirmed by taking swab samples and submitted for the usual RT-PCR test."We have issued an advisory and the NABL accredited labs will have to procure the testing kits. ICMR has approved two kits. We are ready for the tests and are waiting for the labs to procure the kits," said principal health secretary Rajan N Khobragade.Even as the state government is waiting for NABL-accredited labs as well as labs approved by ICMR for Covid-19 to procure testing kits approved by ICMR or FDA for the purpose, the state health department has issued an advisory in this regard. The tests will be performed on Covid-19 suspects or symptomatic high-risk contacts that were negative by RT-PCR (present testing method), high-risk healthcare workers and localities where a cluster of severe acute respiratory infection cases without diagnosis has been reported as well as those who recovered from severe acute respiratory infection."This is not the first time that we are doing rapid testing in the state. We have done it before during the dengue outbreak, SARS, Nipah and so on. Whenever there is an increase in the number of viral diseases, rapid tests have been advised by the WHO,’’ said Dr Amar Fettle, state nodal officer for infectious diseases.The advisory makes it clear that antibody-based rapid tests "need not be used as a primary diagnostic test". As per the advisory, the main use of the test is to study the incidence and prevalence of disease and local outbreaks by well-designed surveillance centres. "They will be used in a limited manner to screen new arrivals from within or outside the country and those who test positive may be quarantined," the advisory states."Once the kits are available here, we will prepare a detailed protocol for testing in the community," added Kerala State Planning Board member and well-known public health expert B Eqbal.