FeedbackOver the past 16 years, WHO has endorsed a range of diagnostic technologies (Table 1.1.1). The WHO assessment process for TB diagnostics has recently evolved to focus on evaluating classes of TB diagnostic technologies rather than specific products. Class determination is managed by WHO/GTB for new diagnostic testing technologies, and it includes an evaluation of the following characteristics:
- purpose of use (i.e. detection of TB or drug-specific resistance);
- principle of action;
- infrastructure and human resource requirements;
- complexity of the testing procedure and associated instrumentation;
- reporting method (automated versus manual); and
- intended setting of use (e.g. reference or peripheral low-complexity, near point-of-care).
These characteristics are compared between the new technology and each of the existing classes already recommended by WHO. When characteristics differ from existing classes, the new technology will undergo an evidence review as “first-in-class” via Pathway A (described below). When characteristics match those of an existing class, the new technology will undergo a “within-class” assessment (Pathway B below).
1.2.1 Pathway A
New technologies will require a Pathway A review if they differ from technologies in existing classes in terms of the characteristics listed above. Evidence synthesis and review and development of recommendations will be conducted through the established WHO/ GTB guideline development process using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. If recommended by a GDG after evidence review, technologies will be referred for WHO prequalification assessment (as available). If a prequalification assessment procedure is not available, the WHO/GTB recommendation will stand until the prequalification procedure becomes available and is successfully completed.
1.2.2 Pathway B
Technologies will require a Pathway B review if they share characteristics with an existing class and are therefore not first-in-class. Review of these within-class technologies depends on availability of a prequalification assessment procedure for the class:
- If a prequalification assessment procedure is available, manufacturers may proceed directly with assessment.
- If a prequalification assessment procedure is not yet available, an evidence review will be conducted through a WHO/GTB evidence assessment process, facilitated by the Technical Advisory Group on TB Diagnostics and Laboratory Strengthening. If recommended by WHO/GTB, the technology will be added to the relevant class in the latest policy guidance. The recommendation will stand until the prequalification assessment procedure becomes available and is successfully completed.