Low-molecular-weight heparin may alter point-of-care assay for international normalized ratio.

Study Objective: To compare the international normalized ratio (INR) measured by a point-of-care testing device with that measured by a reference laboratory method for patients receiving either warfarin only or warfarin plus low-molecular-weight heparin (LMWH).

Design: Retrospective study.

Setting: Outpatient anticoagulation clinic.