Table 2– Sensitivity, specificity and likelihood ratios (LRs) of Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) assay#
SamplesSamples n1) Gold standard: MTC-positive culture or clinical diagnosis of TB2) Gold standard: MTC-positive culture
Sensitivity %Specificity %Positive LRNegative LRSensitivity %Specificity %Positive LRNegative LR
Biopsy specimens
 All36888.3 (82–95)1000.186.6 (79–94)95.519.10.1
 Adults26784.7 (76–93)1000.182.5 (73–92)95.618.70.2
 Children101100 (100–100)1000.0100 (100–100)96.327.30.0
Pleural fluid
 All33044.4 (21–67)1000.633.3 (9–57)99.035.20.7
 Adults29233.3 (9–57)1000.716.7 (0–38)98.915.50.8
 Children38100 (100–100)1000.0100 (100–100)1000.0
Gastric aspirate
 All22478.7 (68–89)1000.277.6 (67–88)97.632.40.2
 Adults5066.7 (36–97)1000.362.5 (29–96)97.726.90.4
 Children17481 (70–91)1000.280 (69–91)97.633.10.2
Pus
 All19587.3 (78–96)1000.185.1 (75–95)94.615.70.2
 Adults8681.6 (69–94)1000.276.7 (61–92)85.75.40.3
 Children109100 (100–100)1000.0100 (100–100)1000.0
CSF
 All13385.7 (67–104)99.1102.00.184.6 (65–104)98.350.80.1
 Adults86100 (100–100)1000.0100 (100–100)98.881.00.0
 Children4775.0 (45–105)97.429.20.375.0 (45–105)97.429.20.3
Urine
 All13087.5 (71–104)99.199.70.184.6 (65–104)96.624.70.2
 Adults11292.3 (78–106)99.091.40.190 (71–109)96.122.90.1
 Children1866.7 (13–120)1000.366.7 (13–120)1000.3
Cavitary fluids
 All9450 (19–81)1000.550 (19–81)1000.5
 Adults8750 (15–85)1000.550 (15–85)1000.5
 Children750 (0–119)1000.550 (0–119)1000.5
Total
 All147481.3 (77–86)99.8490.50.279.0 (74–84)97.328.80.2
 Adults98077.6 (71–84)99.9636.60.273.5 (66–81)96.923.90.3
 Children49486.9 (80–93)99.7335.50.186.3 (80–93)98.248.30.1
 Smear positive12799.0 (97–101)95.823.80.099.0 (97–101)74.23.80.0
 Smear negative134770.3 (63–77)99.9831.00.365.5 (58–73)97.931.60.3
  • 95% confidence intervals are presented in parentheses. MTC: Mycobacterium tuberculosis complex; TB: tuberculosis; CSF: cerebrospinal fluid. #: in the evaluation versus the gold standard including the culture only, two samples from patients lacking of a confident diagnosis (2) (one smear-positive biopsy from an adult and one smear-negative gastric aspirate from a child) were included in the analysis.