Learning Center
New In Coagulation
Thursday, July 10, 2008
Ask the Experts about Emergency Medicine Management
What Is the Value of "Baseline Coagulation" Studies in Patients Starting Low-Molecular-Weight Heparin and Warfarin Therapy?
Robert D. Glatter, MD, FAAEM
Medscape Emergency Medicine. 2008; ©2008 Medscape
http://www.medscape.com/viewarticle/575254
Critical pathways exist in many hospitals for treating patients with a suspected or confirmed diagnosis of venous thromboembolism (VTE). Some pathways call for “baseline laboratory studies,â€Â including prothrombin time (PT), activated partial thromboplastin time (aPTT), and International Normalized Ratio (INR). However, based on the mechanism of newer medications such as LMWH, the clinical value of these baseline laboratory studies prior to initiating outpatient anticoagulation for VTE has been called into question.
LMWH has a greater bioavailability and longer half-life than unfractionated heparin; and has a more predictable anticoagulant allowing LMWH to be given once or twice daily and eliminate the need for laboratory monitoring. This is excreted renally.
In otherwise well-appearing patients without a history of renal insufficiency, increased bleeding tendency, or recent anticoagulation, routine baseline testing (PT/INR and PTT) is not indicated in patients with documented VTE who are treated with LMWH and warfarin, and discharged from the ED. The potential cost savings from a reduction in laboratory testing should serve as motivation for implementation of such a practice pattern.
Donna Castellone
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