Xpert test for TB proven fast and effective in developing country
4 May 2011
The effectiveness of the Cepheid Xpert MTB/RIF test for
tuberculosis and rifampicin resistance in realistic healthcare field
conditions has been reported in a study in The Lancet.
The study demonstrates that the test can effectively be
used in low-resource settings to simplify early and accurate
diagnosis of patients. The potential impact is a reduction in the
morbidity associated with diagnostic delay, dropout and
The study was published online on 19 April 2011 and in volume 377
on 30 April 2011. One of the authors, Prof. Mark Nicol of the
University of Cape Town (South Africa) who contributed to this
a European and Developing Countries Clinical Trials Partnership
(EDCTP) Senior Fellow.
EDCTP was created in 2003 as a European response to the global
health crisis caused by the three main poverty-related diseases
(PRDs) of HIV/AIDS, tuberculosis and malaria. Currently EDCTP is a
partnership between 14 European Union member states plus Norway and
Switzerland with 47 sub-Saharan African countries.
The aim of the programme is to accelerate the development of new or
improved drugs, vaccines and microbicides against HIV/AIDS, malaria
and tuberculosis through promoting the integration of national
programmes of EDCTP European Member States and development of a
genuine partnership with African counterparts.
Professor Mark Nicol of the University of Cape Town has conducted
a study on the impact of the test at clinic and patient level: The
impact of rapid genotypic detection of multi-drug resistant
tuberculosis on treatment outcome in a semi-rural region of South
Africa. In other studies the test showed high sensitivity in
diagnosing TB in both smear-positive as well as smear-negative,
culture-positive individuals including detection of the presence of
This cluster randomised study aimed to determine the impact of
rapid testing with Xpert MTB/RIF when compared to the routine
diagnostic algorithm. The primary impact outcomes to be assessed
were the time between the first presentation to clinic of a patient
with symptoms and the start of appropriate treatment for TB and,
secondly, the proportion of patients in each arm with undiagnosed TB
two months after the first TB test.
One of the tests is a cartridge-based, automated diagnostic test
that can identify Mycobacterium tuberculosis (MTB) and
resistance to rifampicin (RIF) called the GeneXpert MTB/RIF. This
test utilises a real time polymerase chain reaction (PCR)
amplification system that processes an integrated specimen and is
design ed for use at or close to the point of care.
Already, the preliminary results of this study formed a substantial
component of a report submitted to the WHO Strategic and Technical
Advisory Group (STAG) for Tuberculosis that endorsed the use of
GeneXpert to diagnose TB in December 2010. The National Health
Laboratory Service of South Africa is evaluating the possibilities
of rolling out GeneXpert testing for routine services. The data from
this study will be central to informing this policy decision.
The project has established working relationships with the
Foundation for Innovative New Diagnostics (FIND) and the grantee and
his team are consortium members of the TB Clinical Diagnostics
Research Consortium led from Johns Hopkins University of USA. The
team are also co-investigators on the EDCTP sponsored TB-NEAT
consortium led by Professor Keertan Dheda. Funding from the Wellcome
Trust will allow extension of the project to a second laboratory
site and, in particular, to the follow up period beyond the term of
this EDCTP grant.
The overall study of the effectiveness of
the test comprised sites in South Africa, Uganda, Azerbaijan, India,
Philippines and Peru. It was funded by the Foundation for Innovative
New Diagnostics, the Bill & Melinda Gates Foundation, the European
and Developing Countries Clinical Trials Partnership, the Wellcome
Trust and the UK Department for International Development.
1. Boehme CC, et al. Feasibility, diagnostic accuracy,
and effectiveness of decentralised use of the Xpert MTB/RIF test for
diagnosis of tuberculosis and multidrug resistance: a multicentre
implementation study. The Lancet, Volume 377, Issue 9776,
Pages 1495-1505, 30 April 2011. doi:10.1016/S0140-6736(11)60438-8.
2. Information on the Xpert test from Cepheid: