Tuberculosis assays: past, present and future.

Recent developments in the field of TB diagnostics, including the introduction of the Xpert MTB/RIF assay in field testing, raise the hope for faster and more accurate identification of active TB patients. However, there are still many issues that need to be addressed as no point-of-care tests are yet available. Furthermore, no tests are available which are universally applicable to all patients. Improvements in the microbiological and molecular-based approaches are promising and the diagnostic pipeline is encouraging. Host markers associated with active disease may hold promise, especially in situations where sputum diagnostics are problematic, including in children, HIV-infected individuals and in the case of extrapulmonary TB.