Comparative Yield of Tuberculosis during Active Case Finding Using GeneXpert or Smear Microscopy for Diagnostic Testing in Nepal

This study compared the yield of tuberculosis (TB) active case finding (ACF) interventions
applied under TB REACH funding. Between June 2017 to November 2018, Birat Nepal Medical Trust
identified presumptive cases using simple verbal screening from three interventions: door-to-door
screening of social contacts of known index cases, TB camps in remote areas, and screening for
hospital out-patient department (OPD) attendees. Symptomatic individuals were then tested using
smear microscopy or GeneXpert MTB/RIF as first diagnostic test. Yield rates were compared for each
intervention and diagnostic method. We evaluated additional cases notified from ACF interventions
by comparing case notifications of the intervention and control districts using standard TB REACH

The project identified 1092 TB cases. The highest yield was obtained from OPD screening at hospitals (n = 566/1092; 52%). The proportion of positive tests using GeneXpert (5.5%, n = 859/15,637) was significantly higher than from microscopy testing 2% (n = 120/6309). (OR = 1.4; 95%CI = 1.12–1.72; p = 0.0026). The project achieved 29% additionality in case notifications in the intervention districts demonstrating that GeneXpert achieved substantially higher case-finding yields. Therefore, to increase national case notification for TB, Nepal should integrate OPD screening using GeneXpert testing in every district hospital and scale up of community-based ACF of TB patient contacts nationally.

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