A randomised controlled trial (RCT) to evaluate a scalable active case finding intervention for TB using a point-of-care molecular tool (Gene Xpert)

Our Story

The TB reservoir of transmission remains concentrated in large peri-urban settlements in Africa and Asia. They are frequently minimally symptomatic but remain infectious. The danger with minimal symptoms is that people tend to refrain from going to the hospital for diagnosis and treatment until they feel very ill. However, the community will continue to be at risk of infection. Actively seeking TB-positive patients in the community – regardless of degree of symptoms – can help break the chains of TB transmission and, hopefully see patients initiating treatment much sooner.

aims of the study


Determine optimal physical placement of Xpert


model cost effectiveness of an ACF strategy using Xpert at POC (battery operated in a mobile van) versus centralized laboratories factoring in transmission of TB.


bio-phenotype microbiologically confirmed but minimally symptomatic TB patients who are detected as part of an ACF strategy using microbiological characteristics, and novel cough aerosol and imaging technologies-

GeneXpert® (Xpert)

A sensitive, low-cost, same-day test that does not require very advanced training to use. This makes it a promising tool, especially in areas where highly trained laboratory scientists and technicians might not be present. Fortunately, portable versions of the test have become available, meaning that it can even be located in a mobile mini-clinic – making Active Case Finding (ACF) more feasible! 

However, there is need to methodologically optimise the ACF model. XACT-III aims to determine where Xpert should be optimally placed from a physical location point-of-view (i.e. installation in mobile mini clinics vs centralised laboratories (status quo) with samples being sent to the laboratories). Sending collected samples to centralised laboratories is easier because it uses existing infrastructure. However, between 20 and 40% of patients fail to collect their results (pre-treatment loss to follow-up; PTLF). Using the diagnostic in the mobile mini van (at point-of-care; POC) dramatically reduces this PTLF, enabling quick diagnosis and interrupting transmission. Thus, we aim to find out which strategy is most cost-effective yet rapidly picks up the most cases and minimises transmission.

Program Team

Prof Keertan Dheda

Programme PI

Dr J Mutsvangwa

Programme Co-PI

Ashley N Chizema

Programme coordinator

Caroline Maposhere

Programme ACSM coordinator