Some Indian states complained that the kits had a 5 per cent accuracy rate. They were tested on patients that had already tested positive but with negative results for antibodies.
Mumbai (AsiaNews) – India has cancelled orders for about half a million rapid coronavirus test kits from China after they were found to be defective.
China rejected India’s claim, insisting on the quality of its medical products. For Ji Rong, a spokesperson for China’s embassy in New Delhi, “It is unfair and irresponsible [. . .] to label Chinese products as 'faulty' and look at issues with pre-emptive prejudice.”
Rapid testing detects antibodies in the blood of people who may have been infected by the coronavirus. They take about 30 minutes to deliver a result and can help the authorities to quickly understand the scale of the infection in any given area. However, they do not test for the coronavirus itself, and several scientists have raised concerns over their use as a diagnostic tool.
Initially, various Indian states pushed the Indian Medical Research Council (ICMR) to allow testing, even though the latter was reluctant. Eventually, the states began complaining that the kits had an accuracy rate of only 5 per cent. The kits were used on patients already known as positive, but the tests came up with a "negative" result for antibodies.
The kits then failed quality checks by the ICMR. And on Monday, the issue was further complicated after the Delhi high court capped the price of the tests and suggested that the government had overpaid.
Conversely, officials told local media that the government would "not lose a single rupee" from cancelling the order as they had not paid the amount in advance, and had cancelled the entire shipment.
Dr Pascoal Carvalho, a member of the Pontifical Academy for Life, spoke to AsiaNews about the issue. The doctor, who holds Post Doctorate in Immunology on a World Health Organisation (WHO) fellowship, explained that specific antibodies, also known as Immunoglobulins (Ig), are proteins formed in the body after an infection and are usually detected in the serum when the foreign proteins (known as antigens) have been neutralised.
An antibody test tries to ascertain the immune status of the individual. Usually antibody tests detect IgM and IgG. Hence IgM would indicate an early infection and IgG would indicate that the person has either recovered or is on the road to recovery from the infection.
All antibody tests have a limited use, in screening, as indicative tests and do not confirm the infection. Only confirmatory tests can detect the virus itself. In the case of COVID-19, for any antibody test to be effective, it must be very specific.
Now slowly, more and more evidence is emerging indicating the possible existence of many strains of COVID-19 due to mutations. Thus, a test made for the Chinese population will not give the same results as a test for other population groups. Hence, there may be many false positive and false negative results depending on the viral strains in different regions.
In order to develop a valid test to screen the Indian population, scientists will have to perform antibody tests that can detect antibodies against the specific viral strains prevalent in the Indian population or tests that can detect all known strains of the virus.
Indian scientists have the technological knowhow and well-equipped laboratories needed to design and make specific tests. Thus, rather than rely on imported kits for screening, ICMR and the Drug Controller should encourage and fund the development of tests on a priority basis and assist scientists by making available known positive and negative blood samples for testing in-house developed kits.
This way it will be possible to have screening kits with a very high sensitivity and specificity tailored for the Indian population.