Active Tuberculosis case finding using portable radiography reveals high undetected burden in rural Himachal Pradesh

Background Active Case Finding (ACF) in tuberculosis (TB), a provider-initiated, systematic, community-based screening process targets high-risk populations and is used across India including Himachal Pradesh as a strategy to eliminate TB. Himachal Pradesh reports a disproportionately high proportion of extra-pulmonary TB (EP-TB) compared with the national average. An implementation study deploying portable digital X-ray devices in Kangra district as part of ACF identified structural barriers to case detection. Methods 146 villages of Block Dadasibha (population 1,15,766 ) in Kangra district were covered through preliminary screening of 20,207 high-risk individuals by Accredited Social Health Activist (ASHA) followed by screening camps using hand held x-rays and sputum smear examination of suspects held on weekdays using fixed facility and outreach approach. All X-rays were read by a single pulmonologist. NIKSHAY portal data for Kangra District (Year 2024, N = 2,952 cases) were used to benchmark expected prevalence and disease-type distribution. Results 7,969 people (770 chest symptomatic and 6,694 high-risk individuals) reported for TB screening at camps. Of these, 7,409 underwent X-ray screening using handheld devices, with 704 cases flagged as X-ray suggestive. Sputum testing was completed for 650 individuals, with only 2 confirmed as TB positives. The benchmark district NIKSHAY data revealed a TB notification rate of 193 per 100,000; 36.6% of these as EP-TB; 60.6% of cases were in the 20–59-year age group and only 37 (1.3%) were detected through ACF. Discussion The low ACF yield of our implementation study like the benchmark is explainable by four quantifiable structural barriers: (1) high EP-TB proportion (2) weekday-only camp timing (3) mobility barriers that reduced attendance among the elderly (4) residual factors. Together these barriers account for the entire observed gap between expected (14.3) and detected (2) case. Conclusion Effective TB screening in this setting requires a multilayered, context-adapted strategy each layer calibrated to the local epidemiological and geographic context.