Evaluation of a Novel Test

Abstract This chapter draws together the whole book using the example of Xpert MTB/RIF, a novel test for tuberculosis (TB) that has recently been introduced and evaluated. It gives a brief history of TB diagnostics including difficulties encountered following the HIV pandemic then presents a seminal paper from 2010 describing the high diagnostic accuracy of Xpert MTB/RIF. The chapter then explains that appropriate diagnostic research was not carried out but instead researchers carried out diagnostic intervention research which failed to show any impact on patient-relevant outcomes and how, despite this, the World Health Organization has continued with the widespread roll-out of Xpert MTB/RIF. It explains the World Health Organization target product profiles for TB diagnostics and how these are inadequate to determine if a test will improve patient outcomes.