Table 4. Diagnostic indices of various biomarkers in plasma and amniotic fluid to predict MIAC, IAI, and microbial-associated IAI.
| Variables | Area (± SE) under the ROC curve | 95% CI | Cut-off valuea | Sensitivityb (95% CI) | Specificityb (95% CI) | PPV | NPV | |
|---|---|---|---|---|---|---|---|---|
| MIAC | ||||||||
| Plasma LBP, µg/mL | 0.63 ± 0.05c | 0.54–0.72 | 5.62 | 66.7 (53.3–78.3) | 53.7 (43.9–63.4) | 44.4 | 74.4 | |
| AF LBP, µg/mL | 0.63 ± 0.05e | 0.54–0.72 | 0.18 | 61.0 (47.4–73.5) | 57.0 (47.1–66.5) | 43.9 | 72.6 | |
| AF PTX3, ng/mL | 0.86 ± 0.03d | 0.80–0.93 | 4.06 | 74.1 (61.0–84.7) | 90.7 (83.5–95.1) | 81.1 | 86.6 | |
| AF resistin, ng/mL | 0.85 ± 0.03d | 0.78–0.92 | 77.07 | 78.0 (62.3–87.7) | 85.0 (76.9–91.2) | 74.2 | 87.5 | |
| Serum CRP, mg/dL | 0.61 ± 0.05 | 0.52–0.70 | 0.37 | 58.3 (44.9–70.9) | 58.3 (48.5–67.8) | 43.8 | 71.6 | |
| AF IL-8, ng/mL | 0.86 ± 0.03 | 0.80–0.92 | 3.31 | 78.0 (65.3–87.7) | 89.8 (82.5–94.8) | 80.7 | 88.2 | |
| IAI | ||||||||
| Plasma LBP, µg/mL | 0.65 ± 0.05c | 0.55–0.74 | 5.86 | 67.1 (54.9–78.0) | 64.3 (54.0–73.7) | 57.3 | 73.3 | |
| AF LBP, µg/mL | 0.72 ± 0.04e | 0.64–0.80 | 0.15 | 73.9 (61.9–83.8) | 57.7 (47.3–67.7) | 55.4 | 75.7 | |
| AF PTX3, ng/mL | 0.96 ± 0.01d | 0.93–0.99 | 1.31 | 92.6 (83.7–97.6) | 87.6 (79.4–93.4) | 84.0 | 94.4 | |
| AF resistin, ng/mL | 0.94 ± 0.02d | 0.91–0.98 | 54.63 | 89.9 (80.2–95.8) | 87.6 (79.4–93.4) | 83.8 | 92.4 | |
| Plasma IGFBP-3, ng/mL | 0.69 ± 0.04c | 0.61–0.77 | 875.90 | 77.1 (65.6–86.3) | 53.1 (42.7–63.2) | 54.0 | 76.5 | |
| Serum CRP, mg/dL | 0.67 ± 0.04 | 0.59–0.76 | 0.39 | 62.9 (50.5–74.1) | 67.3 (57.1–76.5) | 57.9 | 71.7 | |
| AF IL-8, ng/mL | 0.97 ± 0.01 | 0.94–0.99 | 2.80 | 87.0 (76.7–93.9) | 96.9 (91.3–99.4) | 95.2 | 91.4 | |
| Microbial-associated IAI | ||||||||
| Plasma LBP, µg/mL | 0.64 ± 0.05c | 0.54–0.74 | 5.86 | 68.0 (53.3–80.5) | 59.3 (49.9–68.3) | 41.5 | 81.4 | |
| AF LBP, µg/mL | 0.70 ± 0.05e | 0.61–0.79 | 0.22 | 63.3 (48.3–76.6) | 69.2 (60.0–77.4) | 46.3 | 81.8 | |
| AF PTX3, ng/mL | 0.93 ± 0.02d | 0.90–0.97 | 4.06 | 88.5 (69.9–97.6) | 92.4 (84.2–97.2) | 79.3 | 96.1 | |
| AF resistin, ng/mL | 0.92 ± 0.02d | 0.88–0.96 | 77.07 | 89.8 (77.8–96.6) | 84.6 (76.8–90.6) | 71.0 | 95.2 | |
| AF IGFBP-3, ng/mL | 0.61 ± 0.05e | 0.51–0.71 | 750.32 | 65.3 (50.4–78.3) | 53.8 (44.4–63.1) | 37.2 | 78.8 | |
| Serum CRP, mg/dL | 0.65 ± 0.05 | 0.55–0.75 | 0.46 | 60.0 (45.2–73.6) | 66.9 (57.7–75.3) | 43.5 | 79.8 | |
| AF IL-8, ng/mL | 0.93 ± 0.02 | 0.89–0.97 | 3.31 | 89.8 (77.8–96.6) | 89.0 (81.9–94.0) | 77.2 | 95.5 | |
MIAC = microbial invasion of the amniotic cavity, IAI = intra-amniotic inflammation, SE = standard error, ROC = receiver-operating characteristic, CI = confidence interval, PPV = positive predictive value, NPV = negative predictive value, LBP = lipopolysaccharide binding protein, AF = amniotic fluid, PTX3 = pentraxin 3, CRP = C-reactive protein, IGFBP = insulin-like growth factor-binding protein, IL = interleukin.
aCut-off values corresponding to the highest sum of sensitivity and specificity; bValues are given as % (95% CI); c P > 0.05 compared to serum CRP by the method proposed by DeLong et al.; d P > 0.05 compared to AF IL-8 by the method proposed by DeLong et al.; e P < 0.001 compared to AF IL-8 by the method proposed by DeLong et al.