Table 4.
Test performance in association with therapy, assigning ward and infection source.
| patient subgroup | test performance characteristics (95% CI) | blood culture (BC) | BAC BSI | SeptiFast (SF) | |
|---|---|---|---|---|---|
| antimicrobial therapy | no (n = 81, 35% BSI) | ROC-AUC | 0.91 (0.82–0.96) | 0.91 (0.83–0.96) | 0.88 (0.78–0.94) |
| % PPV | 86.2 (70.7–94.2) | 92.3 (75.3–97.9) | 100 (–) | ||
| % NPV | 94.2 (84.8–97.9) | 92.7 (83.7–96.9) | 88.3 (79.9–93.5) | ||
| yes (n = 112, 36% BSI) | ROC-AUC | 0.67 (0.58–0.76) | 0.89 (0.82–0.94)a | 0.76 (0.67–0.83) | |
| % PPV | 77.3 (57.5–89.5) | 91.9 (78.8–97.2) | 100 (–) | ||
| % NPV | 73.3 (67.8–78.2) | 90.7 (83.2–95.0) | 78.0 (72.2–82.9) | ||
| assigning ward | emergency room (n = 16, 63% BSI) | ROC-AUC | 0.95 (0.72–1) | 0.87 (0.61–0.98) | 0.85 (0.59–0.98) |
| % PPV | 100 (−) | 90.0 (59.8–98.2) | 100 (−) | ||
| % NPV | 85.7 (48.3–97.5) | 83.3 (42.9–97.1) | 66.7 (43.7–83.8) | ||
| intensive care unit (n = 25, 36% BSI) | ROC-AUC | 0.60 (0.39–0.79) | 0.94 (0.77–1)b | 0.89 (0.70–0.98)c | |
| % PPV | 60.0 (23.4–88.1) | 100 (−) | 100 (−) | ||
| % NPV | 70.0 (58.7–79.3) | 94.1 (71.6–99.9) | 88.9 (70.2–96.4) | ||
| standard care (n = 87, 35% BSI) | ROC-AUC | 0.81 (0.71–0.88) | 0.89 (0.81–0.95) | 0.80 (0.70–0.88) | |
| % PPV | 87.0 (68.3–95.4) | 89.3 (73.2–96.2) | 100 (−) | ||
| % NPV | 84.4 (76.4–90.0) | 91.5 (82.9–96.0) | 82.6 (75.4–88.0) | ||
| standard care oncology/hematology (n = 65, 29% BSI) | ROC-AUC | 0.71 (0.58–0.81) | 0.89 (0.79–0.95)d | 0.75 (0.63–0.85) | |
| % PPV | 71.4 (47.1–87.5) | 94.1 (69.5–99.1) | 100 (–) | ||
| % NPV | 80.4 (72.4–86.5) | 91.7 (82.1–96.4) | 81.8 (74.4–87.5) | ||
| infection source | Unknown (n = 96, 24% BSI) | ROC-AUC | 0.79 (0.68–0.86) | 0.87 (0.78–0.93) | 0.81 (0.72–0.89) |
| % PPV | 75.9 (54.9–88.1) | 94.7 (71.7–99.2) | 100 (−) | ||
| % NPV | 88.2 (81.6–92.6) | 92.2 (85.5–95.9) | 88.9 (82.7–93.1) | ||
| Respiratory tract (n = 47; 32% BSI) | ROC-AUC | 0.57 (0.42–0.71) | 0.95 (0.85–0.99)e | 0.73 (0.58–0.85) | |
| % PPV | 60.0 (21.8–89.0) | 83.3 (63.0–93.6) | 100 (−) | ||
| % NPV | 71.4 (65.7–76.6) | 100 (–) | 80.0 (71.4–86.5) | ||
| Urinary tract (n = 19, 42% BSI) | ROC-AUC | 0.83 (0.59–0.96) | 0.83 (0.59–0.96) | 0.75 (0.50–0.92) | |
| % PPV | 85.7 (47.0–97.6) | 85.7 (47.0–97.6) | 100 (−) | ||
| % NPV | 83.3 (59.7–94.4) | 83.3 (59.7–94.4) | 73.3 (57.9–84.6) | ||
| Central venous catheter (n = 14, 86% BSI) | ROC-AUC | 0.63 (0.34–0.86) | 0.92 (0.65–1.00) | 0.88 (0.59–0.99) | |
| % PPV | 90.0 (68.4–97.4) | 100 (−) | 100 (−) | ||
| % NPV | 25.0 (5.8–64.5) | 50.0 (22.0–78.0) | 40.0 (20.0–64.0) | ||
| Others (n = 17, 59% BSI) | ROC-AUC | 0.95 (0.73–0.99) | 0.95 (0.73–1.00) | 0.85 (0.60–0.97) | |
| % PPV | 100 (−) | 100 (−) | 100 (−) | ||
| % NPV | 87.5 (52.2–97.8) | 87.5 (52.2–97.8) | 70.0 (47.5–85.7) | ||
BSI = bloodstream infection according to the adapted European Centre for Disease Prevention and Control criteria; ROC-AUC = receiver operating characteristic-area under the curve; PPV = positive predictive value; NPV = negative predictive value; CI = confidence interval; aBAC BSI vs. BC: p < 0.001 and BAC BSI vs. SF: p = 0.028, bBAC BSI vs. BC: p = 0.007, cSF vs. BC: p = 0.049, dBAC BSI vs. BC: p = 0.020,eBAC BSI vs. BC: p < 0.001 and BAC BSI vs. SF: p = 0.020 as assessed by the Hanley & McNeil test.