Updated on 20 February 2013
The recent trend is the scale up of GeneXpert and the efforts made to make it more affordable. The use of this test will definitely increase in India, and if it can replace TB serology, that will be a welcome move. Several newer molecular tests are entering the market, including a product by Molbio, an Indian company (joint venture between Tulip Group and BigTec Labs).
Researchers are working on all fronts for early diagnosis, detecting drug resistance and also to find better treatment options. Recently, breath-based TB screening test has been reported to have improved performance at two clinical sites in India and Philippines. It needs further stringent evaluation and may have the potential to be useful as a TB screening tool as a point-of-care diagnostic in future.
Dr Ranjan K Nanda, scientist, International Center for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India, is hopeful about the recently developed molecular-based tests, as these have proven to have high sensitivity and specificity. However, he also speaks of the limitation of these tests in terms of the infrastructure required for effective use. "I think the culture test will remain as a gold standard and capacity building for these tests should be given high priority in every state of our country. TB and/or HIV incidence rates could be taken as an important factor for locating places for culture test," added Dr Nanda.
According to Dr Sanjay Sarin, regional director, global health, central and south Asia Pacific, Becton Dickinson (BD), "Over the last few years, there has been a very high level of interest in the development of new tools for TB diagnosis. Recent research trends in TB diagnosis are focused on developing faster, simpler point-of-care tests including biomarker-based assays, manual nucleic acid amplification tests, colorimetric drug susceptibility testing methods, and improved tests for detection of latent TB infection."
Meanwhile, a consortium of private labs coordinated by Clinton Health Access Initiative (CHAI), New Delhi, India, is being put together in India, to make WHO-endorsed tests much more affordable in the private sector. This consortium will likely begin operations by end of February 2013, and will offer three WHO endorsed products namely GeneXpert, Hain GenoType MTBDRplus test for multidrug-resistant tuberculosis (MDR-TB), and Mycobacteria Growth Indicator Tube (MGIT) liquid culture at much lower costs.