The launch in India of Genedrive – a diagnostic product to detect drug-resistant tuberculosis developed by British firm Epistem – has been questioned by medical experts, including the Indian Council for Medical Research. They have cited a study that claims that the test has poor accuracy.

Epistem introduced the product in India on April 18 along with Xcelris Labs, a company in Ahmedabad. Epistem obtained its import license last April, said Chris Gardner, from Consolium Strategic Communications, which is handling the public relations for the company.

India is the only place the diagnostic device has only been launched so far, this despite the fact that the Indian Council of Medical Research and the Revised National TB Control Programme have not approved of it.

Standards not met, says paper

This is not the first time diagnostic tests available in the private sector have come under the scanner. Diagnostic tests that claim to test samples for dengue have also been criticised for showing up false positives for dengue – meaning that patients test positive for the disease when they may not have it at all.

In the case of Genedrive, a recent study showed that the test threw up many false negatives – so a person with TB would possibly not be detected as suffering from the disease. The study, published in the Journal of Clinical Microbiology in February, stated that Genedrive did not meet World Health Organisation-recommended performance standards.

This could have drastic consequences for a patient. “Based on the study, low sensitivity of the Genedrive test means that patients with TB will be missed by this test,” said Dr Madhukar Pai, director of the Montreal-based McGill University’s Global Health Programs, in an email interview. “This can worsen the disease and also increase the chances of TB being transmitted to others in the community.”

Accurate diagnosis of TB has always been challenging in India. A serology test that claimed to detect TB and was available in the private sector was banned in 2012 as it has no scientific basis.

Genedrive was also tested briefly in National Institute for Research in Tuberculosis in Chennai last year. “When they came to us, we tried to evaluate it with a pilot with just about 100 patients,” said Dr Soumya Swaminathan, director-general of the Indian Council of Medical Research, who was earlier heading National Institute for Research in Tuberculosis when the British firm approached them. "It was not up to global standards. We did not do a proper study after that."

Questions about modifications

The test is supposed to detect resistance to primary TB infection, one of the first-line TB drugs, rifampicin, and the DNA of the bacteria. “It could not detect all the mutations, especially the ones found in India," said Dr Swaminathan. They [the company representatives] told us that they would evaluate it properly and get back to us.”

Genedrive is comparable to another rapid diagnostic device, GeneXpert, which was approved by the WHO in 2010. GeneXpert can detect drug-resistant TB in about two hours. The first GeneXpert was installed in Mumbai and India now has 121 machines.

Genedrive is smaller than GeneXpert, portable, and battery-operated. “Genedrive units are also much lower cost than GeneXpert and have a wide operating environment capability,” said Gardner, the company's spokesperson, in an email interview.

The paper, possibly the only one that evaluated the performance of the device, also mentioned that Epistem “was working on the modification of the device”.

When asked about this, Gardner said, “After the study was published, Epistem made changes to system calibration, sample preparation method and some clarification to instructions for use. With the test now just launched in India, we are satisfied with how it is performing.”

But how do we know whether these modifications work? Dr Pai said that "if the company is making changes to improve performance, then adequate validation trials must be conducted before its use on patients in India".

The Central Drug Standard Control Organisation said that their evaluation process is rigorous. “Before anyone can make claims, it has to be evaluated," said GN Singh, the Drugs Controller of India. "One needs to prove these claims."

However, with a large portion of the patients still seeking private-sector care for TB, the chances of mismanagement become higher if these tests are available in the sector. “Patients may not be able to differentiate between what a reliable and unreliable test is,” said Dr Swaminathan. “The problem is the laws are too weak for diagnostic tests in our country. Unlike drugs, it is much easier to get marketing approvals for diagnostic tests. There is no third-party validation."

Standards have been set only for testing the human immunodeficiency virus, by National Institute of Virology, she said.