With quality issues surfacing as States began to use rapid antibody test kits for Covid-19 surveillance, the Centre on Tuesday instructed the States to not use the kits for the next two days.

The kits, which facilitate finger-prick tests, are used for population surveillance purposes.

Rajasthan, which has received close to 10,000 kits from the Indian Council of Medical Research (ICMR), has conducted 170 tests since April 17 on blood samples of patients who had already tested positive for Covid-19 on confirmatory RT-PCR tests, to verify the accuracy of the kits. The rapid kits had only 5.4 per cent accuracy, said State Health Minister Raghu Sharma.

Need for probe

R Gangakhedkar, Head, Infectious Diseases, at ICMR, said that after one State had complained that the detection rate was low, an inquiry was conducted with three more States. “We should not underestimate such findings. When compared against positive RT-PCR samples, the variation of results swayed between 6 per cent and 71 per cent. This is not a good sign...when the variation is so high, this needs to be investigated. Such tests come in crude forms and we may need to refine them,” he said.

The ICMR has advised States to not use the kits while it engages experts from its eight institutes to validate kit lots. Gangakhedkar said that when a sample of the kits was earlier validated in central labs, their detection rate was found to be up to 71 per cent.

The ICMR had earlier stated that the batch-by-batch quality control responsibility lay with the manufacturer. However, Gangakhedkar has now said that if there are issues with certain batches as detected by central teams, this will be conveyed to the Chinese companies that make them.

The Centre has procured 5 lakh kits worth an estimated ₹26 crore from Chinese companies such as Guangzhou Wondfo Biotech and Zhuhai Livzon Diagnostics. The kits arrived in India on April 16 and, by April 17, they were already distributed to the States.

Chhattisgarh, for instance, received 4,000 kits of Livzon make, while Gujarat received 24,000 kits of Wondfo’s. Gujarat too has internally raised the issue of a few tests ‘failing.’

Chhattisgarh utilised 200 of these kits on April 20 in Kathgora hotspot and found only one positive case. He was earlier tested negative on RT-PCR. "We wanted to run more tests to see what this means, but now that the centre has asked us not to use the kits supplied by them, we are halting testing based on those kits," clarified a state health official

The ICMR has validated 14 rapid antibody test kits companies — nine domestic and five foreign, mostly Chinese and Korean. Only the Chinese companies have been able to supply the kits till date.

Chhattisgarh separately purchased 75,000 additional kits from South Korean company SD Biosensors, but has not conducted any State-level quality checks as the ICMR has already approved the firm. “We are banking on ICMR to have approved the competent companies from whom to purchase effective and reasonably (60 to 70 per cent) reliable tests. Cross-checking is surely advisable and something to be done,” said the State’s Health Minister TS Singh Deo.

ICMR’s protocol recommends rapid antibody tests for any person in a hotspot, after seven days of them showing flu-like symptoms. A person who tests positive is quarantined for the next seven days and referred to a hospital if the symptoms appear or worsen; one who tests negative is still advised a one-week quarantine. If a clinician deems fit, lab-based RT-PCR tests can be run on the suspect cases, too, the advisory stated. They are also needed to follow the precautions of social distancing, wear masks, avoiding unnecessary travel and frequently wash hands.

Central teams in West Bengal

Meanwhile, the Ministry of Home Affairs (MHA) has stated that central teams sent to make a ground-level assessment of the situation in West Bengal have not received cooperation from State and local authorities in Kolkata and Jalpaiguri. The MHA has directed the Chief Secretary of West Bengal to ensure that the central teams can effectively carry out their work.