Evaluation of the feasibility, accuracy, and effect of a rapid point-of-care serological triage test for active TB (SeroSelectTB) in high burden, HIV-endemic African settings: a multi-centre, parallel-group, randomised, controlled trial

Background:

New diagnostic tools are essential to curb the global tuberculosis (TB) pandemic. The lack of a rapid and widely accessible triage test that is easy to perform without laboratory facilities is one of the main reasons for unacceptable delay in diagnosis and treatment. A rapid triage test used at health-posts will hasten same-day referral, confirmatory testing and timely TB treatment. Expedient diagnosis will reduce the pool of infection below the critical reproductive rate for Mycobacterium tuberculosis (Mtb) and potentially curb the TB pandemic.

We have developed a rapid serological triage test, SeroSelectTB, for the detection of active TB that is suitable for use in high burden countries. It is crucial that a triage test for TB detects only active disease because latent TB infection is prevalent, but not a target for treatment in high burden countries (HBC). Using laboratory-based immunochemical techniques, we have compared antigens recognized by antibodies from patients and community controls recruited from TB endemic regions, and identified combinations that differentiate between active disease and latent infection even in the context of HIV coinfection. We have thus demonstrated proof-of-principle.

Photo: C. Holm-Hansen

Objectives

Our primary objective is to qualify the performance of SeroSelectTB and determine the extent to which the test reduces diagnostic delay and expedites treatment. This will be achieved in multi-centre randomised controlled trials at health-posts in partner countries. Our secondary objective is to conduct cost-effectiveness evaluations of SeroSelectTB to support a value proposition to national and international stakeholders including regulatory authorities, and to support commercialization requirements.

Photo: C. Holm-Hansen

Impact

A reliable rapid triage test will make it possible to identify and selectively treat those with active TB at the local healthcare level, and thereby reduce diagnostic delay and transmission. Importantly, same-day referral will hasten the detection of drug resistant TB and initiation of adequate treatment regimens. Therefore, the expected impact includes accurate same-day diagnosis of patients with active TB, reduction of diagnostic delay and TB transmission (including drug-resistant TB), and diagnostic cost-savings for patients and healthcare systems in HBC.

Photo: C. Holm-Hansen

Relevance

Using the data generated in field trials and economic evaluations, we will seek SeroSelectTB authorisation from national and international regulatory agencies, commercialization and implementation in HBC. SeroSelectTB will be a valuable cost-effective and easy-to-use addition to routine laboratory-based TB diagnostic methods. The collaborative network and administrative structure of this project are designed to achieve ideal cross-institutional interactions, necessary technology transfer for successful test development, and local capacity building.

Photo: C. Holm-Hansen

©2020 by SeroSelectTB