Direct thrombin inhibitors (DTI) are a class of anticoagulants that act by directly inhibiting thrombin to delay clotting.These drugs are typically used during heparin-induced thrombocytopenia and in acute coronary syndrome.Argatroban is a DTI, and is commonly monitored using clotting based methods such as the activated partial thromboplastin time (aPTT).Such indirect monitoring methods, however, may provide an inaccurate estimation of DTI levels when certain interfering factors are present.Consequently, inaccurate determinations of DTI levels carry the risk of life-threatening bleeding complications as there are no reversal agents for these drugs.Thus, an underestimation of argatroban has the potential to exacerbate certain clinical conditions and lead to extended coagulopathy.