Abstract
The inadequate ability to rapidly and accurately diagnose active tuberculosis (TB) in developing countries remains a major obstacle in global control of the disease.(1) When appropriately diagnosed and treated, TB is largely curable. Yet, in 2010, an estimated 8.8 million people became ill with TB, of which 3.1 million with active disease were not diagnosed and notified to national TB control programs.(2) To enable widespread use in resource-constrained settings, new diagnostic tools for TB are needed urgently.
Currently available diagnostic technologies—including smear microscopy and culture—have notable shortcomings. While technological advances have brought about largely incremental improvements, more profound change may be seen with new or expected diagnostics, particularly nucleic acid amplification technologies (NAAT). In 2010, WHO endorsed GeneXpert® MTB/RIF, an automated, bench-top device that tests for TB and rifampicin resistance. It returns results within hours, is relatively easy to use, and can be used at decentralized health levels.
Despite its advantages, however, the diffusion of GeneXpert® MTB/RIF is not without challenges: it is still relatively expensive, is not a point-of-care (POC) test, does not eliminate the need for drug sensitivity testing, and will require some evaluation to determine its most effective use in resource-constrained environments. The pipeline promises new technologies, including a POC manual NAAT kit using loop-mediated isothermal amplification from Eiken / FIND, and a handheld NAAT device from Epistem / Xcelris. However, these products require further development and validation, and are not expected to be widely commercially available until the end of 2012 or later.
