Reproducibility of different laboratory tests for heparin monitoring in clinical practice
| Assay | Within-run variability | Number of measurements | Day-to-day variability | Number of measurements |
| CV | CV | |||
| aPTT | 5.7% | 10 | 3.7% | 15 |
| TT 2 (low) | 14.7% | 10 | 6.1% | 15 |
| PiCT | 2.5% | 10 | 1.1% | 15 |
| Anti-Xa | 3.4% | 10 | 5.0% | 15 |
aPTT, activated partial thromboplastin time; CV, coefficient of variation (%); PiCT, prothrombinase-induced clotting time; TT 2, thrombin time 2 (7.5 U/mL bovine thrombin).