India suffered a major setback yesterday after the results of rapid antibody testing kits from China to examine cases of coronavirus infection proved faulty, Rajasthan ordered a halt in the tests and the Indian Council of Medical Research (ICMR) asked all states to follow suit. Following complaints from the states, the ICMR banned rapid tests across the country for two days. India has been forced to take this decision at a time when preparations were on to increase testing even more. Shoddy kits from China were gutted amidst preparations for mass testing in hotspots. Let’s try to understand how heavy this ‘betrayal’ of China will prove to India.
So far, 5.5 lakh rapid antibody test kits have arrived from China to India. The ICMR has warned that the kits may need to be replaced. Whether or not the Indian government trusts China, it thought the rapid test kits were needed for large-scale testing, the demands for which were increasing every day.
After a positive test, the suspect’s Reverse Transcription – Polymerase Chain Reaction (RT-PCR) test is done for final confirmation. Sirf News has explained earlier how the two tests differ.
Now that the rapid tests have stopped, it will be difficult for India because the virus outbreak is worsening. Now, if the consignment of these kits from China turns out to be a mess, one can guess how bad the test will be in the country whereas testing is a great weapon in humanity’s war against coronavirus.
A rapid test gives quick results and is less expensive, due to which it was used on a large scale. India’s testing strategy is that large-scale rapid tests should be conducted in areas with hotspots for quick results. This involves monitoring those found positive in quarantine or isolation and sending their swab sample for RT-PCR test to allow for final confirmation. But this testing kit of China ‘deception’ has given a big blow to India’s testing strategy.
In a rapid test, within minutes or in an hour, blood is used to detect the response to the virus. It is checked whether coronavirus is responding to the body’s antibodies that are supposed to fight the infection. If the response to antibodies is seen, it is believed that the virus’s ability to infect has met with some resistance.
The problem with this approach is that the result is inconclusive. According to Lung Surgeon Arvind Kumar at Sir Gangaram Hospital in Delhi, if a person is infected but there is no response to antibodies in his body, the results in the rapid test will be negative.
Scientist and doctor Ajay Mahalka from the Netherlands echoed the Dr Kumar’s medical opinion in a conversation with a private news channel on Wednesday. Dr Mahalka said that timeframe was very important in a rapid test. It may take time for the body to show the antibody response after infection. He said, “If I am infected today and have a rapid test today, the results will not be positive.”
When experts are saying that the result of the infected person in the rapid test turns out to be positive, it is equally possible that there is no flaw in the rapid test kit from China. The disturbances are due to the limitations of this test. In other words, it can be argued in favour of China that the principle that works in this method is prima facie flawed and, therefore, wherever the rapid test kits are imported from, the results will be erroneous. How it is this argument that is flawed follows.
It is not merely healthy patients testing negative and infected ones testing negative. Repeatedly, it was seen in the case study of Rajasthan that there is variance in the results of the tests on a given person in a short period of time. That implies that the Chinese product is malfunctioning.
The RT-PCR test, meanwhile, has proved reliable. It is a lab technique that detects viruses by adding reverse transcription to the DNA of RNA. In this, swab samples are taken from people’s throats, nose or mouth, which is based on RNA. That is, in this test, evidence of the RNA genome of the virus is found in the patient’s body.
The RT-PCR may take from a day or two to yield results. It is, of course, expensive. Now the government needs to take a call as to whether its priority is to save money and keep China in good humour while getting a misleading medical picture of India or to spend more and be sure that the results are right.
Remember, the word “rapid” in the term is a misnomer. It cannot be the deciding factor even if India applies the test on a mass scale. As explained above, both the rapid test kits and the RT-PCR method take 24-48 h to bear results.
The writer is a haematologist