The Tuberculosis Diagnostic Pipeline
Clarify not only which tools work but also which ones do not work.
A 2006 report by FIND and the WHO’s Special Programme for Research and Training in Tropical Diseases (TDR) estimated that the world annually spent $1 billion on TB diagnostics. In the absence of strong regulatory oversight of TB diagnostics, the WHO needs to provide clear guidance clarifying not only which tools are effective but also which ones are not useful to ensure funds are not wasted on unvalidated diagnostic tests. As part of this effort, the TDR conducted a systematic review of 19 serological tests in 2008 to examine their utility in diagnosing TB. The review showed that the serological tests were much less specific and sensitive than the sputum-smear test and should not be used for diagnosis. The WHO is convening an expert committee in July 2010 to examine all data available regarding the utility of serological tests to diagnose TB, and STAG-TB will likely provide clarification of what role these tests will or won’t play in TB control efforts (World Health Organization 2006, 2008a). Accelerate targeted development of a point-of-care assay for all forms of TB disease.
New TB diagnostic development has opportunistically taken advantage of tools that were already in late-stage development. Many of the tools recommended by WHO put existing tools into public health facilities of countries with high-TB burden where they were not previously utilized or in lower rungs of the health system. However, the result has been that tools that fill certain critical gaps are only practical at district and referral laboratory settings. There is an increasing recognition that these tools at the higher levels of health systems will only contribute to a revolution in TB diagnostics if they are complemented by a point-of-care (POC) TB diagnostic, such as a dipstick, appropriate for use at the health post setting. However, a clear project-driven plan that is focused on a POC dipstick that has clearly defined minimum specifications has not been articulated. Such a product specification needs to drive a coordinated funding and scientific effort to meet this most urgent gap in TB diagnostics. To develop such a product specification, TAG, Médicines Sans Frontières (MSF), and Partners in Health convened a group of experts in March 2009 that included basic researchers, product developers, laboratory technicians, activists focused on improving TB care, and TB program implementers. This group developed the minimum specifications required for a TB POC dipstick (Treatment Action Group 2009). While discussing the TB POC specifications, a number of barriers to developing such a tool were identified. These included the need for specimen banks that have samples relevant for the development of a TB POC test from well-characterized patient populations as well as coordination and collaboration between research efforts to identify 119