Accurate and affordable tests can help control TB

Accurate and affordable tests can help control TB

Tuberculosis (TB) takes a heavy toll on Indians. Every year, India reports over two million TB cases.

 TB is one of the leading causes of death in the country. In the past few years, untreatable forms of drug-resistant TB cases have been reported in urban areas.TB mostly affects the lungs and the most important symptoms include chronic cough for two weeks or more and fever. If TB is diagnosed quickly and if 6 months of antibiotics are taken regularly, nearly all patients can be fully cured.

Unfortunately, TB patients in India are often diagnosed very late (after two months or more), and after they have seen several doctors. A majority of Indians seek first contact medical care in the private sector. For TB care, patients often begin seeking advice in the informal private sector (chemists and unqualified practitioners), then seek care from qualified practitioners, and eventually end up in the public sector for free treatment. Patients often move from one provider to another, before they are finally diagnosed and put on TB treatment. And while they do this, they continue to transmit the infection to others. Hence, Accurate and early diagnosis are critically important to control TB.

TB testing practices in the private sector are completely different from those in the public sector. All over the world, sputum is the most important sample for diagnosis of lung TB and every guideline recommends the use of sputum-based tests. But, for several reasons, including poor regulation and financial incentives, blood is the most popular sample in the Indian private sector. Unfortunately, it is not possible to detect TB in blood samples. In 2012, the government of India banned the use of antibody blood tests for TB, and has discouraged the use of tests like “TB Gold” and “TB Platinum” for active TB.

Tests vital

The question now is how can good, sputum-based TB tests replace the inappropriate blood tests in the private sector? There are four accepted sputum tests that are recommended by the World Health Organisation (WHO) and these are also used by the Indian national TB programme. This includes the traditional sputum smear test where the TB bacteria are seen under a microscope. Although not highly accurate, this test is still useful (and inexpensive) and should be more widely used in the private sector. Recently, the WHO endorsed a new, rapid, two-hour DNA test called Xpert which can diagnose TB with great accuracy and can also detect those with drug-resistance. This test has high accuracy – it can pick up nearly 90 per cent of all TB cases.

There is another DNA test called line probe assay and this test can also detect drug-resistance with high accuracy. Lastly, liquid culture, where bacteria are grown in tubes, is considered the gold standard for TB diagnosis and is the only test that can detect resistance to all major TB drugs. However, liquid culture takes two weeks to produce results.

If private physicians and laboratories replace blood tests with the above sputum tests, this should greatly help improve accuracy of TB diagnosis for patients in India. The challenge is that good tests like GeneXpert, line probe assay and liquid culture are expensive in the private sector. For example, the GeneXpert test can cost the patient as much as Rs 3000 or higher in private laboratories. This is because WHO-endorsed tests are available at specially negotiated low prices only to the public sector, and import duties also add to the costs. In addition, financial incentives and laboratory margins further inflate the costs to make them virtually unaffordable to the average private sector patient.

New initiative

Thankfully, a new initiative was launched in 2013, to improve the affordability of WHO-endorsed TB tests. Initiative for Promoting Affordable, Quality TB tests (IPAQT is a consortium of private labs in India, supported by industry and non-profit groups (like the Clinton Health Access Initiative), that has made several WHO-approved tests available at affordable prices to patients in the private sector. Labs in IPAQT have access to lower, negotiated prices for the quality tests in exchange of their commitment to pass on the benefits to patients.

Thanks to IPAQT, which operates on a high-volume, low-margin model, the cost of GeneXpert is now reduced to Rs 2000 (maximum price labs can charge patients). The line probe assay (Hain Genotype MTBDRplus) is now available at Rs 1600. Liquid cultures are available at Rs 900. These prices are about 50 per cent less than the private market prices before IPAQT was launched. TB cases diagnosed will be notified to the government for linkages to free TB drugs, where necessary. 

Since its launch nearly a year ago, IPAQT has steadily grown – with over 60 labs across the country now providing these tests at affordable prices. Thus, this initiative has increased affordability for private sector patients, and is improving the quality of TB diagnosis in the country. The IPAQT initiative has already received international attention as an interesting model to engage private laboratories in TB control, with coverage in publications such as the Wall Street Journal and 2013 WHO Global TB Report.
(The writer is professor at McGill University, Montreal, Canada)

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