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Use of coagulometers by home health nurses could reduce costs of monitoring the homebound elderly taking warfarin

Use of portable coagulometers for monitoring the blood of homebound elderly patients taking the anticoagulant warfarin could save money and potentially improve quality of care, concludes a study supported by the Agency for Healthcare Research and Quality (HS10133). Warfarin is often used to treat elderly patients who have suffered a stroke, heart attack, or atrial fibrillation (fast, irregular heartbeat that can lead to stroke). Monitoring patients on warfarin is needed to ensure that their blood does not become so thin that it precipitates internal bleeding or so thick that it causes a stroke or other blood clot.

Portable coagulometers can be used to measure the prothrombin time (time required for clot formation) and calculate the international normalized ratio (INR, ideal blood thickness; target INR in this study was 2.0-3.0) from a drop of whole blood.

Home health nurses traditionally draw blood samples from homebound patients and take the specimens to a central laboratory or a designated drop-box for INR determinations. Principal investigator Brian F. Gage, M.D., M.Sc., of the Washington University School of Medicine, St. Louis, and colleagues compared the cost of this approach with the cost of using a point-of-care coagulometer for 35 elderly patients receiving cardiac home health care and long-term oral anticoagulation.

The researchers totaled the costs for materials, procedures, transportation, and labor for both methods. The cost of INR determination by the portable coagulometer was significantly less than the traditional method ($6.86 vs. $17.30). A plot of 180 paired INR values obtained by the coagulometer and traditional INR showed close agreement below an INR value of 3.5 but increasing scatter for higher values. The authors conclude that the cost savings and potential improvement in quality of care argue for equipping home health nurses with portable coagulometers.

See "Cost-savings analysis of using a portable coagulometer for monitoring homebound elderly patients taking warfarin," by Dorothy S. Cheung, M.D., Diane Heizer, R.N., Janice Wilson, R.N., and Dr. Gage, in the September-October 2003 American Journal of Geriatric Cardiology 12(5), pp. 283-287.

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