Tuberculosis diagnostic utilization in Oromia Region, Ethiopia: a cross‑sectional study on extent and associated factors

Background Tuberculosis (TB) remains a leading cause of morbidity and mortality in Ethiopia, yet the utilization of confirmatory and supportive diagnostic tests is not adequately characterized. This study assessed the extent of TB diagnostic utilization and identified associated factors in health facilities of Oromia Region, Ethiopia. Methods A quantitative cross‑sectional study was conducted from December 2023 to August 2024. Using stratified random sampling, 112 health facilities (31 hospitals, 42 health centers, 38 public‑private facilities, and 3 referral laboratories) were included, along with 222 health professionals. Sample size was determined using the WHO Service Availability and Readiness Assessment (SARA) methodology. Data were collected using adapted WHO SARA tools via electronic Kobo Collect. Descriptive statistics, logistic regression (with Hosmer‑Lemeshow goodness‑of‑fit and variance inflation factor diagnostics), Pearson correlation, and multiple linear regression were used for analysis. Sensitivity analyses were conducted using 2.7%, 5%, 7.5%, 10%, and 15% presumptive TB prevalence assumptions. Results Over six years (2018–2023), confirmatory TB tests increased modestly from 35,038 to 48,935 despite a rise in outpatient attendees from 2.3 to 6.6 million. Community‑level test utilization averaged < 8%, and facility‑based utilization remained below 11% across all sensitivity assumptions. The overall test positivity rate was 8.7%, with Xpert positivity stable at 10% and LF‑LAM positivity fluctuating between 16.8% and 33.3%. Bacteriologically confirmed TB cases accounted for only 40.6% of notified cases. Rifampicin DST coverage increased from 30% to 80.7%, but second‑line DST remained below 36%. Among health professionals, 75.2% (95% CI: 69.5%–80.9%) perceived diagnostic utilization as inadequate. In multivariate analysis of facility-level data, lack of a certified microscopist (aOR = 0.249, 95% CI: 0.073–0.845, p = 0.026), larger catchment population (aOR = 1.516 per doubling, 95% CI: 1.112–2.065, p = 0.008), and absence of a formal sample transport system (aOR = 13.893, 95% CI: 4.597–41.982, p < 0.001) were significantly associated with low diagnostic utilization. Private-for-profit management showed borderline significance (aOR = 4.480, 95% CI: 0.943–21.277, p = 0.059). The perception-based model identified low patient flow (OR = 0.018, 95% CI: 0.001–0.218), inadequate supply (OR = 0.023, 95% CI: 0.002–0.299), and no information about sample referral systems (OR = 0.006, 95% CI: 0.000–0.112) as significant predictors. Multiple linear regression revealed that X-ray tests (β = 0.940, p = 0.002) and OPD visits (β = 0.557, p = 0.044) were positively associated with TB case detection. Conclusion TB diagnostic utilization in Oromia Region was substantially lower than expected demand based on presumptive TB prevalence, with major gaps in confirmatory testing, DST coverage, and chest X‑ray use. Systemic barriers including supply shortages, equipment failure, and weak referral systems were associated with low utilization and represent priority areas for intervention. Strengthening sample transport systems, ensuring certified microscopist availability, and integrating TB screening into routine OPD services are critical interventions.