ANTICOAGULANT-THERAPY MONITORING WITH INTERNATIONAL NORMALIZED RATIO AT US ACADEMIC HEALTH CENTERS

OBJECTIVE: To assess the extend of incorporation of international norm alized ratio (INR) reporting in US academic hospitals. DESIGN: Survey of academic hospital clinical laboratories in January 1995. SETTING/PA RTICIPANTS: Fifty-eight academic hospitals clinical laboratories at in stitutions that are members of the University HealthSystem Consortium. MAIN OUTCOME MEASURES: The methods for monitoring oral anticoagulant therapy at the surveyed laboratories were determined. The extent of re porting of prothrombin time (PT), PT ratio, INR, and INR therapeutic r ange was determined. RESULTS: All 58 of the responding hospital clinic al laboratories reported INR in patients receiving oral anticoagulatio n. The median length of time that hospitals had been reporting INR was 24 months (range 3-108). A majority of hospitals continued to report PT values (95%) and PT reference ranges (93%) in addition to INR. Ther apeutic INR ranges were reported by only 25 of the laboratories (43%). Of those that report INR ranges, many follow the published recommenda tions by the American College of Chest Physicians and the Food and Dru g Administration. A majority of the hospitals (79%) do not confirm the accuracy of the international sensitivity index (ISI) for their own a nalyzers. CONCLUSIONS: Contrary to previous reports, academic hospital clinical laboratories have now adopted the more accurate system of re porting INR values in addition to PT values in patients receiving oral anticoagulation. However, better reporting of INR ranges, use of more sensitive thromboplastins, and confirmation of the accuracy of the IS I for local analyses would further improve the monitoring of oral anti coagulation.