Cost and affordability analysis of TB-LAMP and Xpert MTB/RIF assays as routine diagnostic tests in peripheral laboratories in Malawi and Vietnam

Abstract

Background: While the incidence of tuberculosis (TB) is declining globally, the rate of decline is far too slow to meet the 2035 end TB targets. Use of rapid molecular diagnostics that can be deployed in peripheral settings has the potential to address gaps in TB care cascade, improve case detection, and ultimately limit the ongoing transmission of the disease. Methods: We assessed the costs and affordability of 2 commercial nucleic acid amplification test (NAAT)-loop-mediated isothermal amplification assay for TB (TB-LAMP) and Xpert MTB/RIF (Xpert)-used at the peripheral laboratories in Malawi and Vietnam. Costs were assessed from the health service provider perspective using bottom-up method. Categorized documentation of resources uses for each diagnostic test was done using a standardized time-and-motion form directly observing each laboratory procedure. Affordability was assessed as a proportion of total first-year implementation and operational costs of respective diagnostics against the national TB program budget for 2014. Results: Unit costs of TB-LAMP and Xpert varied depending on the daily test volumes and the test kit costs were the primary cost driver. Unused equipment capacity costs were also an important cost driver at low testing volumes and was more significant for Xpert. Weighted average pertest cost of nationwide implementation of respective diagnostics was between $14.37-$15.85 for TB-LAMP and $20.06-$26.86 for Xpert for Vietnam and Malawi. Both NAATs would account for a significant portion of or exceeded the national TB program budget if complete nationwide roll-out to peripheral laboratory were considered. Conclusion: While TB-LAMP is a lower cost alternative to Xpert as an upfront NAAT for TB in peripheral settings, cost-utility against Xpert and other alternatives and optimized implementation strategies must be carefully evaluated through additional model-based studies to better inform policy and program decisions to expand the coverage of rapid diagnostics for TB.