Table 1.

Laboratory assays responsive to NOACs [25, 28, 29]

	Dabigatran	Rivaroxaban	Apixaban	Edoxaban	Issues related to testing
PT	Insensitive at therapeutic concentrations	Normal PT can exclude significant drug levels	Insensitive	Poor sensitivity	Highly variable based on reagent; cannot be standardized across laboratories
aPTT	Normal aPTT can exclude anticoagulation	Insensitive	Insensitive	Dose-dependent prolongation	Highly variable based on reagent; cannot be standardized across laboratories Clinical relevance of recovery unknown
TT	Highly sensitive, must be diluted Normal values can exclude anticoagulation	Insensitive	Insensitive	Insensitive	Preferred assay for dabigatran; reagent-dependent
Anti-FXa	Insensitive	Sensitive when calibrated; normal FXa can exclude anticoagulation	Sensitive when calibrated; normal FXa can exclude anticoagulation	Sensitive when calibrated; normal FXa can exclude anticoagulation	Variable range, interlaboratory variability, not widely available. Preferred assay for rivaroxaban, apixaban, and edoxaban

aPTT activated partial thromboplastin time, FXa direct factor Xa, PT prothrombin time, TT thrombin time