Table 2.
The sensitivity, specificity, positive predictive value, negative predictive value, accuracy and area under the ROC curve of 20WBCT, prolonged PT, prolonged INR and prolonged TT compared to fibrinogen levels <100 and <164 mg/dL.
| Fibrinogen levels (number of laboratory results) | Variable | Unclotted 20WBCT (N = 38) | PT > 13.5 s (10.5–13.5) (N = 64) | INR > 1.2 (0.91–1.17) (N = 65) | TT > 13 s (10–13) (N = 63) |
|---|---|---|---|---|---|
| Number of laboratory abnormal results (%) | 4 (10.5) | 8 (12.5) | 7 (10.8) | 16 (25.4) | |
| <164 mg/dL (N = 30) | Sensitivity (%) | 20.0 | 20.7 | 20.0 | 57.1 |
| Specificity (%) | 100 | 94.3 | 97.1 | 100 | |
| Positive predictive value (%) | 100 | 75.0 | 85.7 | 100 | |
| Negative predictive value (%) | 52.9 | 58.9 | 58.6 | 74.5 | |
| Accuracy (%) | 57.9 | 60.9 | 61.5 | 81.0 | |
| Area under the curve | 0.600 (0.419–0.481) | 0.566 (0.405–0.727) | 0.557 (0.396–0.718) | 0.762 (0.617–0.907) | |
| <100 mg/dL (N = 19) | Sensitivity (%) | 33.3 | 33.3 | 26.3 | 82.4 |
| Specificity (%) | 100 | 95.7 | 95.7 | 95.7 | |
| Positive predictive value (%) | 100 | 75.0 | 71.4 | 87.5 | |
| Negative predictive value (%) | 76.5 | 78.6 | 75.9 | 93.6 | |
| Accuracy (%) | 78.9 | 78.1 | 75.4 | 92.1 | |
| Area under the curve | 0.667 (0.462–0.871) | 0.630 (0.439–0.821) | 0.603 (0.412–0.795) | 0.873 (0.732–1.000) |
ROC: receiver operating characteristic; 20WBCT: 20 minute whole blood clotting test; PT: prothrombin time; INR: international normalized ratio; TT: thrombin time.