New oral anticoagulants which specifically inhibit factor Xa (FXa) or thrombin 
(FIIa) do not require routine laboratory monitoring. However, they induce a 
state of hypocoagulation and increase the risk of bleeding. In some clinical 
situations, such as emergency surgery, hemorrhagic episodes, or recurrent 
stroke, coagulation monitoring may be useful. A significant number of 
publications have reported uncontrollable hemorrhagic complications and deaths 
in patients treated with these new anticoagulants. The selection of the most 
appropriate clotting assay is based on the drug used and the availability of the 
test. The new anticoagulants influence all global clot-based tests. Prothrombin 
time and partial thromboplastin time measured before and after treatment are 
considered as qualitative tests since they are not specific. Specific anti-Xa 
and anti-IIa assays are available and results can be expressed in nanogram per 
milliliter of plasma using calibrated plasmas containing well-established 
amounts of drug. The fact that there is no specific antidote to reverse the 
anticoagulant action of the new anticoagulants can impair management of 
hemorrhagic complications; clinical experience is still limited. Pro-hemostatic 
treatment with non-activated or activated prothrombin complexes (FEIBA(®)), or 
as a last recourse with FVIIa concentrates (NovoSeven(®)), has been used with 
variable results. Some suggestions for the management of patients with bleeding 
have been published but there is still little clinical evidence for these 
interventions.