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Table 2 Odds ratios of paired EMS and spot sputum smear grading and culture time-to-detection for predicting an unfavourable outcome (logistic regression)

From: Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis

Baseline predictor variable EMS Spot
OR 95% CI P value OR 95% P value
Baseline smear grading* ZN Neg 0.63 0.18–2.11 0.45
ZN 1+ 0.50 0.17–1.42 0.19 0.22 0.08–0.63 0.004
ZN 2+ 0.38 0.17–0.87 0.02 0.82 0.48–1.39 0.46
ZN 3+ 0.56 0.33–0.95 0.03 0.68 0.43–1.07 0.09
ZN 4+ Reference Reference
Log10 LJ TTD 0.61 0.26–1.45 0.26 0.73 0.29–1.87 0.51
Log10 MGIT TTP 0.38 0.13–1.10 0.07 0.29 0.08–0.99 0.05
  1. *Unfavourable outcome is associated with increasing ZN smear for both EMS (P = 0.008) and spot (P = 0.002), non-parametric test for trend
  2. CI confidence interval, EMS early morning sputum sample, LJ Lowenstein–Jensen, MGIT mycobacteria growth indicator tube, OR odds ratio, TTD time-to-detection, TTP time-to-positivity, ZN Ziehl–Neelsen