Days after the Indian Council of Medical Research (ICMR) finalised a testing strategy involving the use of rapid antibody tests in clusters or where there is large-scale migration or gatherings, the World Health Organization (WHO) on Friday advised the use of a host of rapid tests only in research settings. This is the latest in a series of divergences in India’s strategy to fight the Novel Coronavirus Disease (COVID-2019) from what the WHO considers appropriate. “However, before these tests can be recommended, they must be validated in the appropriate populations and settings. Inadequate tests may miss patients with active infection or falsely categorize patients as having the disease when they do not, further hampering disease control efforts. At present, based on current evidence, WHO recommends the use of these new point-of-care immunodiagnostic tests only in research settings. They should not be used in any other setting, including for clinical decision-making, until evidence supporting use for specific indications is available,” WHO has said in a scientific brief dated April 8. The WHO brief covers several rapid tests including those that detect both the virus and the antibodies against it. India is currently in the process of introducing rapid antibody tests in some settings. This test screens the plasma for antibodies that the body develops against the virus. It is faster than the usual nucleic acid-based test for the virus- a polymerase chain reaction (PCR) test. The rapid test takes less than 30 minutes. It is important to note however, that only the PCR test is capable of identifying an early infection. Only after the antibodies have developed, which takes several days, can the serological test come in. Even for serological tests, the positives will have to go through the PCR filter. Explained: How Plasma therapy works, what India plans Four days before the WHO document, on April 4, the ICMR issued the advisory to start antibody tests in high density settings. “As a matter of abundant precautions, all symptomatic influenza-like illness (ILI) persons should be advised home quarantine for 14 days. At facility level, symptomatic ILI individuals to be tested using rapid antibody tests.” If the test is positive, “After clinical assessment, treatment in hospital or isolation as per protocol. Action as per protocol to be initiated for contact tracing. If symptoms worsen, refer to designated COVID-19 hospitals. When home quarantine is not feasible, consider facility-based quarantine,” says the advisory. Till date, 16 antibody-based rapid tests have been validated at NIV Pune, On rapid tests based on detection of antibodies, WHO says: “Based on current data, WHO does not recommend the use of antibody-detecting rapid diagnostic tests for patient care but encourages the continuation of work to establish their usefulness in disease surveillance and epidemiologic research.” Here’s a quick Coronavirus guide from Express Explained to keep you updated: What can cause a COVID-19 patient to relapse after recovery? | COVID-19 lockdown has cleaned up the air, but this may not be good news. Here’s why | Can alternative medicine work against the coronavirus? | A five-minute test for COVID-19 has been readied, India may get it too | How India is building up defence during lockdown | Why only a fraction of those with coronavirus suffer acutely | How do healthcare workers protect themselves from getting infected? | What does it take to set up isolation wards?
