Table 1.
Input data
| Parameter | Value (95% CI) | Source |
|---|---|---|
| Mean number of presumptive TB cases per day | 44 (34,55) | Data collated from primary health care facilities in Porto Alegre for the PROVE-IT trial [11] |
| TB prevalence amongst presumptive-TB cases | 15.8% (14.6, 17.0%) | |
| HIV prevalence in TB cases | 44.8% (40.4, 49.2%) | |
| HIV prevalence in no TB cases | 27.3% (25.8, 28.8%) | |
| Sensitivity - Smear microscopy for HIV-positive | 45% (38, 52%) | Boehme et al [35] |
| Specificity - Smear microscopy for HIV-positive | 100% (99, 100%) | |
| Sensitivity - Smear microscopy for HIV-negative | 72% (69, 75%) | |
| Specificity - Smear microscopy for HIV-negative | 99% (99, 100%) | |
| Sensitivity - Xpert for HIV-positive | 82% (77, 87%) | |
| Specificity - Xpert for HIV-positive | 99% (98, 100%) | |
| Sensitivity - Xpert for HIV-negative | 92% (90, 94%) | |
| Specificity - Xpert for HIV-negative | 99% (98, 99%) | |
| Sensitivity - Clinical judgement for HIV-positive | 49% | Estimated from reported TB case volumes in Porto Alegre and assumed sensitivity/specificity of Smear microscopy |
| Specificity - Clinical judgement for HIV-positive | 90% | |
| Sensitivity - Clinical judgement for HIV-negative | 77% | |
| Specificity - Clinical judgement for HIV-negative | 90% | |
| Sensitivity of X-ray for abnormalities suggestive of active TB | 87% (79, 95%) | WHO [26] |
| Specificity of X-ray for abnormalities suggestive of active TB | 89% (87, 92%) | |
| Estimated unit cost per test – Microscopy | US$7.20 | Estimates provided by TB research staff working with the TB program in Porto Alegre |
| Estimated unit cost per test – Xpert | US$ 17.80 | |
| Estimated unit cost per test – X-ray | US$ 6.00 | |
| Estimated % of presumptive-TB cases LTFU | 10.0% | |
| Estimated cost to treat TB case in Brazil | US$840 | Laurence et al [36] |
| Estimated cost to treat MDR-TB in Brazil | US$6313 |