Designing an optimized diagnostic network to improve access to TB diagnosis and treatment in Lesotho.

BACKGROUND

To reach WHO End tuberculosis (TB) targets, countries need a quality-assured laboratory network equipped with rapid diagnostics for tuberculosis diagnosis and drug susceptibility testing. Diagnostic network analysis aims to inform instrument placement, sample referral, staffing, geographical prioritization, integration of testing enabling targeted investments and programming to meet priority needs.

METHODS

Supply chain modelling and optimization software was used to map Lesotho's TB diagnostic network using available data sources, including laboratory and programme reports and health and demographic surveys. Various scenarios were analysed, including current network configuration and inclusion of additional GeneXpert and/or point of care instruments. Different levels of estimated demand for testing services were modelled (current [30,000 tests/year], intermediate [41,000 tests/year] and total demand needed to find all TB cases [88,000 tests/year]).

RESULTS

Lesotho's GeneXpert capacity is largely well-located but under-utilized (19/24 sites use under 50% capacity). The network has sufficient capacity to meet current and near-future demand and 70% of estimated total demand. Relocation of 13 existing instruments would deliver equivalent access to services, maintain turnaround time and reduce costs compared with planned procurement of 7 more instruments. Gaps exist in linking people with positive symptom screens to testing; closing this gap would require extra 11,000 tests per year and result in 1000 additional TB patients being treated. Closing the gap in linking diagnosed patients to treatment would result in a further 629 patients being treated. Scale up of capacity to meet total demand will be best achieved using a point-of-care platform in addition to the existing GeneXpert footprint.

CONCLUSIONS

Analysis of TB diagnostic networks highlighted key gaps and opportunities to optimize services. Network mapping and optimization should be considered an integral part of strategic planning. By building efficient and patient-centred diagnostic networks, countries will be better equipped to meet End TB targets.

Déclaration de conflit d'intérêts

The authors have read the journal's policy and the authors of the manuscript have the following competing interests: This study was funded by UK Aid from the UK government through a grant to the Foundation for Innovative New Diagnostics (FIND). FIND provided support for this study in the form of salaries for employees, HA, KK and ZK, and provided funding to LLamasoft through a consulting services agreement which covered consultancy fees for RP and YW. FIND participated in the development, evaluation and demonstration of the Xpert MTB/RIF assay, and provides technical assistance to countries for roll out. FIND has partnership agreements with various diagnostic manufacturers, including Cepheid Inc. for development and implementation of diagnostic tools. RP is an employee of LLamasoft Inc., a private supply chain management software company that developed and provides consulting services for use of the software used in the study. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.