Prospective Genotyping For Total Hip or Knee Replacement Patients Receiving Warfarin (Coumadin)

Exclusion Criteria

• •Blood transfusion in previous two weeks
• •Participant is already taking warfarin
• •Pre-operative INR \> 4.0
• •Pre-operative bilirubin \> 2.4 mg/dL
• •Current active cancer diagnosis with ongoing treatment
• •Concomitant medications known to exert a major interaction with warfarin such as septra, metronidazole, tramadol, amiodarone, ciprofloxacin, or cimetidine.