Summary of findings 1. Xpert Ultra and Xpert MTB/RIF in cerebrospinal fluid.
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Participants: people presumed to have tuberculous meningitis Prior testing: people who received Xpert Ultra or Xpert MTB/RIF testing may first have undergone a health examination (history and physical examination) and possibly received a chest radiograph Role: initial test, replacement for usual practice Settings: primarily tertiary care centres (the index test was often run in reference laboratories) Index tests: Xpert Ultra and Xpert MTB/RIF Reference standard: solid or liquid culture Studies: cross‐sectional studies Limitations: participants were evaluated exclusively as inpatients at a tertiary care centre, or, if the clinical setting was not reported, Xpert was performed at a reference laboratory rather than at primary care facilities and local hospitals Xpert Ultra pooled sensitivity (95% CrI): 89.4% (79.1 to 95.6); pooled specificity (95% CrI): 91.2% (83.2 to 95.7) Xpert MTB/RIF pooled sensitivity (95% CrI): 71.1% (62.8 to 79.1); pooled specificity (95% CrI): 96.9% (95.4 to 98.0) | |||||
| Xpert Ultra result | 1000 people tested for TB using Xpert Ultra(95% CrI) | Number of participants (studies) | Certainty of the evidence (GRADE) | ||
| Prevalence of 2.5% | Prevalence of 10% | Prevalence of 20% | |||
| True‐positives (participants with TB meningitis) | 22 (20 to 24) |
89 (79 to 96) |
178 (158 to 191) |
89 (6) | ⊕⊕⊝⊝ Lowa |
| False‐negatives (participants incorrectly classified as not having TB meningitis) | 3 (1 to 5) |
11 (4 to 21) |
22 (9 to 42) |
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| True‐negatives (participants without TB meningitis) | 889 (811 to 933) |
821 (749 to 861) |
730 (666 to 766) |
386 (6) | ⊕⊕⊕⊝ Moderateb |
| False‐positives (participants incorrectly classified as having TB meningitis) | 86 (42 to 164) |
79 (39 to 151) |
70 (34 to 134) |
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| Xpert MTB/RIF result | 1000 people tested for TB using XpertMTB/RIF (95% CrI) | Number of participants (studies) | Certainty of the evidence (GRADE) | ||
| Prevalence of 2.5% | Prevalence of 10% | Prevalence of 20% | |||
| True‐positives (participants with TB meningitis) | 18 (16 to 20) |
71 (63 to 79) |
142 (126 to 158) |
571 (30) | ⊕⊕⊕⊝ Moderatec |
| False‐negatives (participants incorrectly classified as not having TB meningitis) | 7 (5 to 9) |
29 (21 to 37) |
58 (42 to 74) |
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| True‐negatives (participants without TB meningitis) | 945 (930 to 956) |
872 (859 to 882) |
775 (763 to 784) |
2824 (30) | ⊕⊕⊕⊕ High |
| False‐positives (participants incorrectly classified as having TB meningitis) | 30 (19 to 45) |
28 (18 to 41) |
25 (16 to 37) |
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Abbreviations: Crl: credible interval; TB: tuberculosis
We included plausible prevalence estimates for the target condition suggested by the WHO. For Xpert Ultra, the median prevalence of tuberculosis in the included studies was 35.2%. For Xpert MTB/RIF, the median prevalence of tuberculosis in the included studies was 15.2%.
Credible limits were estimated based on those around the point estimates for pooled sensitivity and specificity.
aThere were few participants in this analysis. The very wide 95% CrI around true‐positives and false‐negatives may lead to different decisions, depending on which credible limits are assumed. We downgraded two levels for imprecision. bThe wide 95% CrI around true‐negatives and false‐positives would likely lead to different decisions, depending on which credible limits are assumed. We downgraded one level for imprecision. cThe wide 95% CrI around true‐positives and false‐negatives may lead to different decisions, depending on which credible limits are assumed. We downgraded one level for imprecision.
GRADE certainty of the evidence
High: we are very confident that the true effect lies close to that of the estimate of the effect. Moderate: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect. Very low: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.
The results presented in this table should not be interpreted in isolation from results of the individual included studies contributing to each summary test accuracy measure.