Table 1 Performance of Xpert MTB/RIF, AFB smear microscopy and IGRA in detecting PTB, EPTB and TP
From: A retrospective study on Xpert MTB/RIF for detection of tuberculosis in a teaching hospital in China
Sensitivity (95% CI) (%) | Specificity (95% CI) (%) | Positive predictive value (95% CI) (%) | Negative predictive value (95% CI) (%) | |
|---|---|---|---|---|
Presumptive PTB cases (n = 533) | ||||
Xpert MTB/RIF | 88.5 (77.0–94.6) | 99.6 (98.5–99.9) | 95.8 (86.0–98.9) | 98.8 (97.3–99.4) |
AFB smear microscopy | 36.5 (24.8–50.1)b | 99.0 (97.6–99.9) | 79.2 (59.5–90.8) | 93.5 (91.0–95.4) |
IGRA | 96.2 (87.0–98.9) | 55.9 (51.6–60.3) b | 19.1 (14.8–24.3) | 99.3 (97.4–99.8) |
Presumptive EPTB cases (n = 172) | ||||
Xpert MTB/RIF | 76.5 (52.7–90.4) | 99.4 (96.4–99.9) | 92.9 (68.5–98.7) | 97.5 (93.7–99.0) |
AFB smear microscopy | 11.8 (3.3–34.3) b | 99.4 (96.4–99.9) | 66.7 (20.8–93.9) | 91.1 (85.9–94.6) |
IGRA | 82.4 (59.0–93.8) | 67.1 (59.4–74.0) b | 21.5 (13.3–33.0) | 97.2 (92.1–99.0) |
Presumptive TP cases (n = 82) | ||||
Xpert MTB/RIF | 15.0 (5.2–36.0) | 100.0 (94.2–100.0) | 100.0 (43.9–100.0) | 78.5 (68.2–86.1) |
AFB smear microscopy | 0.0 (0.0–16.1) | 100.0 (94.2–100.0) | NA (NA) a | 75.6 (65.3–83.6) |
IGRA | 95.0 (76.4–99.1) b | 45.2 (33.4–57.5) b | 35.9 (24.3–49.3) | 96.6 (82.8–99.4) |
Total (n = 787) | ||||
Xpert MTB/RIF | 69.7 (59.5–78.2) | 99.6 (98.7–99.9) | 95.4 (87.3–98.4) | 96.3 (94.6–97.4) |
AFB smear microscopy | 23.6 (16.0–33.4) b | 99.1 (98.1–99.6) | 77.8 (59.2–89.4) | 91.1 (88.8–92.9) |
IGRA | 93.3 (86.1–96.9) b | 57.5 (53.8–61.1) b | 21.8 (18.0–26.3) | 98.5 (96.8–99.3) |