WHO and the Stop TB Partnership’s New Diagnostics Working Group (NDWG) launched today a framework for the evaluation of new tests for tuberculosis infection. The document provides details on study design, populations, reference standards, sample size calculation and data analysis to guide the future development of these tests.

Approximately a quarter of the world’s population is estimated to be infected with Mycobacterium tuberculosis. Treatment of TB infection, also known as tuberculosis preventive treatment (TPT), aims to prevent the development of TB disease, and is one of the critical components to achieve the ambitious targets of the WHO End TB Strategy.  At the United Nations High-level Meeting (UNHLM) on TB in 2018, countries committed to provide TPT to at least 30 million people in 2018-2022. 

"We urgently need new tests for TB infection to expand access to TB preventive treatment for the millions in need, to stop the onset of disease, avert suffering and save lives," said Dr Tereza Kasaeva, Director, WHO Global TB Programme. "New tests with better operational characteristics which can be easily scaled up in the community are vital to overcome the current challenges of fragile supply lines, high cost, cold-chain requirements, uncertainty about quality-assurance, and appropriate laboratory infrastructure."

This framework for evaluation of new tests for the detection of TB infection has been produced to direct research and to facilitate a standardized evaluation, thus accelerating the adoption of the tests into global and national policy and subsequent scale-up. The document covers technical issues that should be considered when evaluating new tests for TB infection, such as evaluation of the safety of skin tests, costs to the health system and its users, preferred features and operational characteristics. It is intended for manufacturers of diagnostics, researchers, research funders, regulators, TB programme coordinators, civil society and other stakeholders.

"We will not be able to progress towards ending TB without reliable tests to confirm TB infection," said Dr Alberto Matteelli, University of Brescia, Italy and coordinator of the Task Force that prepared the framework document. "Although currently testing for TB infection is not always required before starting TPT, a positive test result will help direct TPT to those would benefit most from treatment and avoid unnecessary medication."