Table 1.

UFH monitoring techniques.

Test	Advantages	Disadvantages
ACT	• Inexpensive • POC • Whole blood test	• Measures end point of the clotting cascade, but does not solely tell you about UFH effect
aPTT	• Accepted means of titrating anticoagulation therapy for both UFH and DTI • POC now available	• High degree of intra- and interpatient variability especially in infants • Less reliable in critical illness
Anti-Xa	• Specific measure of UFH effect based on the ability of UFH to catalyze AT’s inhibition of factor Xa • Better association with UFH dose	• Elevated plasma-free hemoglobin and hyperbilirubinemia will underestimate UFH activity by anti-Xa
TEG/ROTEM	• POC • Whole blood test • Provides information about both clot strength and fibrinolysis	• Limited availability

UFH, unfractionated heparin; POC, point-of-care; AT, antithrombin; DTI, direct thrombin inhibitor; TEG, thromboelastography; ROTEM, rotational thromboelastometry.