Characteristic | Site of isolate collection | Admission | Screening swab and isolate collection | |||
---|---|---|---|---|---|---|
Sterile | Nonsterile | ICU | Non-ICU | Same admission | Different admission | |
True positive, no. | 5 | 45 | 17 | 33 | 43 | 7 |
True negative, no. | 97 | 331 | 179 | 249 | 365 | 63 |
False positive, no. | 1 | 2 | 0 | 3 | 1 | 2 |
False negative, no. | 6 | 23 | 11 | 18 | 20 | 9 |
Sensitivity, % (95% CI) | 45 (17–77) | 66 (54–77) | 61 (41–79) | 65 (50–78) | 68 (55–79) | 44 (31–62) |
Specificity, % (95% CI) | 99 (94–100) | 99 (98–100) | 100 (98–100) | 99 (97–100) | 99 (98–100) | 97 (89–100) |
Positive likelihood ratio (95% CI) | 45 (5.7–348) | 111 (27–443) | –* | 54 (17–170) | 250 (35–1782) | 14 (3.3–62) |
Negative likelihood ratio (95% CI) | 0.55 (0.32–0.95) | 0.34 (0.24–0.47) | 0.39 (0.21–0.6) | 0.36 (0.25–0.52) | 0.32 (0.22–0.46) | 0.58 (0.38–0.9) |
Positive predictive value, % (95% CI) | 83 (36–100) | 96 (86–100) | 100 (80–100) | 92 (77–98) | 98 (88–100) | 78 (40–97) |
Negative predictive value, % (95% CI) | 94 (88–98) | 94 (90–96) | 94 (90–97) | 93 (90–96) | 95 (92–97) | 88 (78–94) |
CI = confidence interval, ICU = intensive care unit.
↵* Test characteristics could not be calculated owing to high specificity values.