Table 4.
Diagnostic Accuracy of DOAC‐Specific Tests to Drug Concentrations <30 ng/mL
| Substance | Coagulation Assay | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | PLR | NLR |
|---|---|---|---|---|---|---|---|
| Dabigatran | HTI | 93.0 (84.5–97.1) | 78.2 (68.2–85.9) | 80.0 (70.6–87.1) | 92.3 (83.4–96.8) | 4.3 (2.8–6.3) | 0.1 (0.0–0.2) |
| BDTI | 90.7 (82.0–95.6) | 98.9 (93.2–99.9) | 98.7 (92.2–99.9) | 91.9 (84.2–96.2) | 83.4 (11.9–586.8) | 0.1 (0.0–0.2) | |
| ECT | 97.7 (91.1–99.6) | 94.3 (86.5–97.9) | 94.4 (86.8–97.9) | 97.6 (90.9–99.6) | 17.0 (7.3–39.8) | 0.0 (0.0–0.1) | |
| Rivaroxaban | Calibrated AXA | 98.2 (93.1–99.7) | 97.1 (82.9–99.8) | 99.1 (94.4–100.0) | 94.3 (79.4–99.0) | 33.4 (4.8–230.3) | 0.0 (0.0–0.1) |
| Uncalibrated AXA <ULN | 98.2 (93.0–99.7) | 64.7 (46.4–79.7) | 90.1 (82.3–94.5) | 91.7 (71.5–98.5) | 2.8 (1.8–4.4) | 0.0 (0.0–0.1) | |
| Uncalibrated AXA <2ULN | 97.3 (91.7–99.3) | 82.3 (64.8–92.6) | 94.7 (88.4–97.8) | 90.3 (73.0–97.5) | 5.5 (2.7–11.4) | 0.0 (0.0–0.1) | |
| Uncalibrated AXA <0.3 U/mL | 92.0 (84.9–96.0) | 94.1 (78.9–99.0) | 98.1 (92.6–99.7) | 78.0 (62.0–88.9) | 15.6 (4.1–60.0) | 0.1 (0.0–0.2) | |
| Apixaban | Calibrated AXA | 73.8 (65.1–81.0) | 96.8 (81.5–99.8) | 98.9 (93.3–99.9) | 47.6 (35.0–60.5) | 22.9 (3.3–157.8) | 0.3 (0.2–0.4) |
| Uncalibrated AXA <ULN | 93.7 (87.5–97.0) | 90.3 (73.1–97.5) | 97.5 (92.4–99.4) | 77.8 (60.4–89.2) | 9.7 (3.3–28.4) | 0.1 (0.0–0.1) | |
| Uncalibrated AXA <2ULN | 81.0 (72.8–87.2) | 96.8 (81.5–99.8) | 99.0 (93.9–99.9) | 55.6 (41.5–68.8) | 25.1 (3.6–172.9) | 0.2 (0.1–0.3) | |
| Uncalibrated AXA <0.3 U/mL | 68.3 (59.3–76.1) | 100 (86.3–100) | 100 (94.7–100) | 43.7 (32.1–55.9) | 0 (n.c.) | 0.3 (0.2–0.4) |
Samples=178 (dabigatran), 146 (rivaroxaban), 157 (apixaban). Test accuracy calculations are provided with 95% confidence intervals. The ULN for anti‐Xa activity as determined by our laboratory is 0.09 U/mL. AXA indicates anti‐Xa activity; BDTI, Biophen direct thrombin inhibitor assay; DOAC, direct oral anticoagulants; ECT, ecarin clotting time; HTI, Hemoclot direct thrombin inhibitor assay; NLR, negative likelihood ratio; NPV, negative predictive value; PLR, positive likelihood ratio; PPV, positive predictive value; ULN, upper limit of normal.