Table 3.
The sensitivity and specificity (with 95% CIs) for CZN, MZN with cytospin, MZN without cytospin, culture, and Xpert compared to clinical diagnosis (definite, probable and possible TBM) as gold standard stratified by site.
| CZN | MZN with cytospin | MZN without cytospin | Culture | Xpert | ||
|---|---|---|---|---|---|---|
| Positive tests | Vietnam | 88/186 | 90/181 | 82/181 | 47/182 | 37/186 |
| South Africa | 9/74 | 7/73 | 7/74 | 20/72 | 13/73 | |
| Indonesia | 32 / 120 | 32/120 | 27/120 | 52/120 | 45/120 | |
| Sensitivity (95% CI) | Vietnam | 47.3% | 49.7% | 45.3% | 25.8% | 19.9% |
| (40.3–54.5%) | (42.5–56.9%) | (38.2–52.6%) | (20.0–32.6%) | (14.8–26.2%) | ||
| South Africa | 12.2 % | 9.6 % | 9.5% | 27.8 % | 17.8 % | |
| (6.5–21.5%) | (4.7–18.5%) | (4.7–18.3%) | (18.8–39.0%) | (10.7–28.1%) | ||
| Indonesia | 26.7% | 26.7% | 22.5% | 43.3% | 37.5% | |
| (19.6–35.2%) | (19.6–35.2%) | (15.9–30.8%) | (34.8–52.3%) | (29.4–46.4%) | ||
| Specificity (95% CI) | Vietnam | 100% | 100% | 99.1% | 100% | 100% |
| (96.8–100%) | (95.2–100%) | |||||
| 100% | 100% | 100% | 100% | 100% | ||
| (96.5–100%) | (96.5–100%) | |||||
| South Africa | ||||||
| Indonesia | 100% | 100% | 100% | 100% | 100% | |
| (74–100%) | (74.1–100%) |
CZN; conventional Ziehl–Neelsen smear, MZN; modified Ziehl–Neelsen smear, culture; mycobacterial culture by MGIT (Becton Dickinson, USA) (Vietnam and South Africa) or MODS (Indonesia), Xpert; Xpert MTB/RIF (Cepheid, USA), CI; confidence interval. No CIs are shown for CZN, culture and Xpert specificity values. These tests are included in the reference gold standard. A positive result will always occur in a definite TBM case; therefore no level of error can be associated with the specificity value. Data shown for 613 patients (5 patients excluded, due to missing clinical diagnostic score for TBM (n = 2), or due to missing baseline lumbar puncture (n = 3)).