TABLE 1.
Effect of anticoagulants on tests used to investigate lupus anticoagulant (LA) as well as other routine coagulation tests
| Anticoagulant | aPTT | SCT | dRVVT | PT | TT | Anti‐Xa assay |
|---|---|---|---|---|---|---|
| Unfractionated heparin | ↑–↑↑↑ (concentration dependent; most reagents do not contain neutralizer) |
↔ (up to ~1 U/ml if contains heparin neutralizer) ↑ (if exceeds or no neutralizer) |
↔ (up to ~1 U/ml if contains heparin neutralizer) ↑ (if exceeds neutralizer) |
↔ (up to ~1 U/ml if contains heparin neutralizer) ↑ (if exceeds neutralizer) |
↑↑↑ | ↑–↑↑↑ (concentration dependent) |
| LMWH | ↑ |
↔ (if contains heparin neutralizer) ↑ (if no neutralizer) |
↔ (if contains heparin neutralizer) | ↔ (if contains heparin neutralizer) | ↑ | ↑–↑↑↑ (concentration dependent) |
| VKAs | ↑ | ↑ | ↑↑ | ↑↑↑ | ↔ | ↔ |
| Dabigatran | ↑↑ | ↑ | ↑↑ | ↑ | ↑↑↑ | ↔ |
| Rivaroxaban | ↑ | ↑↑ | ↑↑↑ | ↑↑ | ↔ | ↑↑↑ |
| Apixaban | ↔–↑ (assay dependent) | ↑ | ↑ (but LA ratio may fall because effect greater on confirmed reagents) | ↔–↑ (assay dependent) | ↔ | ↑↑↑ |
| Edoxaban | ↔–↑ (assay dependent) | ↑ | ↑ | ↔–↑ (assay dependent) | ↔ | ↑↑↑ |
↑, prolongs (the more ↑, the greater the prolongation); ↔, no effect.
Abbreviations: aPTT, activated partial thromboplastin time; dRVVT, dilute Russell's viper venom time; LMWH, low molecular weight heparin; PT, prothrombin time; SCT, Silica clotting time; TT, thrombin time; VKA, vitamin K agonist.