Heparin Monitoring and Patient Safety: A College of American Pathologists Q-Probes Study of 3431 Patients at 140 Institutions

CONTEXT: Appropriate laboratory monitoring of unfractionated heparin therapy promotes effective anticoagulation while minimizing hemorrhagic complications. OBJECTIVES: To measure heparin therapy monitoring in a "real-world" setting and to assess the degree of anticoagulation achieved. DESIGN: One hundred forty institutions abstracted laboratory and pharmacy data from up to 30 inpatients receiving standard-dose unfractionated heparin therapy for 72 hours. Institutions also reported their therapeutic ranges and described heparin prescribing and monitoring policies. RESULTS: Activated partial thromboplastin times or anti-factor Xa levels were measured at least once within the first 12 hours of administration for 95% of 3431 heparinized inpatients. Eighty-seven percent of patients had a platelet count performed within 72 hours of heparin administration. Seventy-eight percent of heparinized inpatients achieved therapeutic anticoagulation within 24 hours, but more than one third of patients entered the supratherapeutic range on at least 2 occasions during the first 72 hours. We found moderate variation in performance among the 140 institutions participating in the study, with more consistency in monitoring patients but less consistency in achieving therapeutic levels of anticoagulation. In one fourth of hospitals, more than half of the heparinized patients entered the supratherapeutic range on 2 or more occasions during the first 72 hours of therapy. None of 20 institutional practices we examined were meaningfully associated with more thorough monitoring of patients or with a higher percentage of patients achieving therapeutic anticoagulation. There was moderately wide variation in therapeutic ranges among the 140 sites. CONCLUSIONS: The prevention of heparin over-anticoagulation represents an important opportunity for improving patient safety in a significant number of institutions.