We celebrate the centennial of the discovery of heparin this year. Even after 100 years, heparin is still one of the most prescribed anticoagulants.  The clinical laboratory plays a central role in the management of patients receiving heparin.  During this webinar, the differences between unfractionated heparin (UFH) and low-molecular-weight-heparin (LMWH) will be described as well as the impact these differences may have relative to monitoring. The traditional surrogate marker(s) used as a means of monitoring and measuring efficacy and safety of UFH and LMWH will be detailed and advantages and disadvantages will be identified with a focus upon reference range and limitations of the aPTT, and the benefit of anti-Xa monitoring of UFH and LMWH. Management strategies for appropriate use of anti-Xa heparin level determinations will be discussed.

• Describe the differences between unfractionated and low molecular weight heparins along with the impact of the formulation differences on monitoring tests.
• Describe details and limitations of monitoring tests to measure safety and efficacy of unfractionated and low molecular weight heparins.
• Discuss advantages of the use of the anti-Xa assay to monitor unfractionated and low molecular weight heparins.