Table 7. Risk factors associated with Xpert MTB/RIF error results.
| Characteristics | Test Result | Total n (%) |
Bivariate Analysis | Multivariate Analysis | ||||
|---|---|---|---|---|---|---|---|---|
| Error | Other results | COR(95%CI) | P—value | AOR(95%CI) | P—value | |||
| Site of specimen | Respiratory | 191 | 1704 | 1895(75.3) | 1.9(1.3–2.8) | 0.001* | ||
| Non-respiratory | 34 | 586 | 620(24.7) | 1.00 | ||||
| Sputum sample quality | Saliva | 35 | 228 | 263(14) | 1.4(0.9–2.3) | 0.107* | ||
| Mucoid | 94 | 879 | 973(51.6) | 1.0(0.7–1.4) | .959 | |||
| Mucopurulent | 0 | 14 | 14(0.7) | 0.0(0.0-) | .999 | |||
| Bloodstained | 7 | 54 | 61(3.2) | 1.2(0.5–2.8) | .636 | |||
| Purulent | 55 | 519 | 574(30.5) | 1.00 | ||||
| Instrument module^ | A-1 | 32 | 283 | 315(12.5) | 6.1(0.8–45.6) | 0.077* | 6.2(0.8–46.5) | .078 |
| A-2 | 6 | 48 | 54(2.1) | 0.0(0.0-) | .998 | 0.0(0.0-) | .998 | |
| A-3 | 19 | 289 | 308(12.2) | 1.0(0.1–16.7) | .990 | 1.0(0.1–46.3) | .993 | |
| A-4 | 41 | 166 | 207(8.2) | 81.0(5.6–1166.3) | .001 | 64.7(4.5–435.2) | .002 | |
| B-1 | 16 | 265 | 281(11.2) | 0.7(0.1–7.0) | .772 | 0.5(0.0–4.2) | .629 | |
| B-2 | 6 | 295 | 301(12.0) | 54.0(4.2–687.7) | .002 | 42.8(3.4–447.9) | .004 | |
| B-3 | 30 | 231 | 261(11.3) | 14.7(1.9–112.1) | .010 | 13.7(1.7–407.5) | .013 | |
| B-4 | 41 | 194 | 235(9.3) | 1.1(0.1–18.5) | .934 | 1.1(0.1–48.6) | .934 | |
| C-1 | 1 | 54 | 55(2.1) | 6.7(0.8–58.1) | .080 | 6.6(0.8–47.3) | .087 | |
| C-2 | 0 | 51 | 51(2.0) | 3.6(0.5–27.1) | .222 | 3.4(0.4–46.4) | .240 | |
| C-3 | 1 | 53 | 54(2.1) | 13.3(1.8–99.3) | .011 | 13.0(1.7–48.3) | .013 | |
| C-4 | 3 | 2 | 5(0.2) | 3.3(0.4–25.1) | .256 | 3.4(0.4–46.3) | .248 | |
| D-1 | 3 | 227 | 230(9.1) | 1.1(0.1–9.3) | .931 | 1.0(0.1–4.2) | .966 | |
| D-2 | 3 | 3 | 6(0.2) | 7.0(0.9–52.6) | .100 | 7.1(0.9–43.9) | .058 | |
| D-3 | 22 | 81 | 103(4.1) | 11.4(1.5–84.9) | .017 | 14.3(1.9–407.5) | .010 | |
| D-4 | 1 | 48 | 49(1.9) | 1.00 | 1.00 | |||
| Tester | Tester-1 | 31 | 368 | 399(15.9) | 2.2(1.1–4.6) | 0.030* | ||
| Tester-2 | 25 | 171 | 196(7.8) | 3.9(1.8–8.3) | .000 | |||
| Tester-3 | 40 | 459 | 499(19.8) | 2.3(1.1–4.7) | .020 | |||
| Tester-4 | 6 | 75 | 81(3.2) | 2.1(0.7–6.0) | .156 | |||
| Tester-5 | 13 | 135 | 148(5.9) | 2.6(1.1–6.0) | .030 | |||
| Tester-6 | 36 | 263 | 299(11.9) | 3.6(1.8–7.5) | .000 | |||
| Tester-7 | 64 | 553 | 617(24.5) | 3.1(1.6–6.1) | .001 | |||
| Tester-8 | 10 | 266 | 276(11.0) | 1.00 | ||||
| Tester experience | < 2 Year (n = 2) | 104 | 1012 | 1116 | 2.3(1.4–4.0) | 0.002* | 2.1(1.1–3.7) | .019 |
| 2–3 Year (n = 4) | 105 | 937 | 1042 | 2.2(1.3–3.9) | .004 | 2.4(1.3–4.4) | .003 | |
| >3 Year (n = 2) | 16 | 341 | 357 | 1.00 | 1.00 | 1.00 | ||
Note: COR; Crude Odds Ratio; AOR, Adjusted Odds Ratio; CI, Confidence Interval; 1.00, Reference
*, Selected variables for multivariate analysis
^, 16 modules GeneXpert instrument