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Table 1 Sputum microscopy and sputum culture results on all specimens

From: Sputum microscopy for the diagnosis of HIV-associated pulmonary tuberculosis in Tanzania

  SC positive SC negative Total
SM positive 1311 24 155
SM negative 81 9108 9189
Total 212 2 9132 9344 3,4
  1. 1 103 patients
  2. 2 DNA probes performed on 166 isolates (94 SM positive, 72 SM negative); 46 additional isolates considered MTB based on growth and culture morphology
  3. 3 Excludes 79 culture contaminated and 31 NTM
  4. 4 Test characteristics of SM:
  5. Sensitivity = 131/212 = 61.8%(95% CI 54.9% -68.4%)
  6. Specificity = 9108/9132 = 99.7% (95% CI 99.6% – 99.8%)
  7. Positive predictive value = 131/155 = 84.5% (95% CI 77.8% – 89.8%),
  8. Negative predictive value = 9108/9189 = 99.1% (95% CI 98.9% – 99.3%)
  9. LR (positive smear microscopy) = 235.1 (95% CI 155.8 – 354.3)
  10. LR (negative smear microscopy) = 0.38 (95% CI 0.32 – 0.45)