Table 2.
Test accuracy for detecting bacterial contamination by glucose and pH screening test
| Screening test | True positive | True negative | False positive | False negative | Accuracy, % (95 % CI) | Sensitivity, % (95 % CI) | Specificity, % (95 % CI) | PPV, % (95 % CI) | NPV, % (95 % CI) | PLR (95 % CI) | NLR (95 % CI) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Glucose alone | 3 | 1282 | 25 | 22 | 96 (95–97) | 12 (4–30) | 98 (97–99) | 11 (4–27) | 98 (97–99) | 6.27 (.05–817.2) | .90 (.82–.98) |
| pH screening | 6 | 1089 | 218 | 19 | 82 (80–84) | 24 (12–43) | 83 (81–85) | 3 (1–6) | 98 (97–99) | 1.44 (.51–4.09) | .91 (.82–1.01) |
| Both glucose and pH | 3 | 1284 | 22 | 22 | 97 (96–98) | 12 (4–30) | 98 (97–99) | 12 (4–30) | 98 (97–99) | 7.12 (.05–937.9) | .90 (.82–.98) |
| Glucose and or pH (at least one of them) | 6 | 1086 | 220 | 19 | 82 (80–84) | 24 (12–43) | 83 (81–85) | 3 (1–6) | 98 (97–99) | 1.43 (.50–4.04) | .91 (.82–1.01) |
PPV indicated positive predictive value, NPV negative predictive value, PLR positive likelihood ratio, NLR negative likelihood ratio
* For one of the platelet concentrates, bacterial contamination base on Bact/Alert system was missing