A GeneXpert IV unit for MTB applications inside the FIND/WHO program © Cepheid
One week into the GeneXpert online panel, discussion is highlighting the critical importance of understanding the local epidemiology for tuberculosis (TB), especially for multidrug-resistant TB (MDR-TB) and also for HIV-associated TB. Prioritizing these two risk groups in diagnostic algorithms that use the Xpert MTB/ RIF as the initial diagnostic test is a key message for the efficient integration of this new tool into existing health systems. But it is by no means the only key message.
For years health implementers in high endemic areas with limited resources have been struggling with the lack of a rapid and reliable diagnostic test for HIV-associated TB and MDR-TB. Hence, the endorsement of the fully-automated nucleic acid amplification test (NAAT) by the WHO in December 2010 has been welcomed with enthusiasm from both implementers and donors. This novel tool reliably detects TB DNA in sputum specimens in less than two hours with 94.4 percent sensitivity for the simultaneous detection of rifampicin resistance with 98.3 percent specificity. Along with the WHO endorsement, many questions have arisen as to how best integrate this technology along with existing TB diagnostic tools in countries, especially those most affected by the disease and with limited resources.
I recently met with Dr. David Bangsberg, who — in addition to being Associate Professor of Medicine at Harvard School of Medicine — is the director of the