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Falsely elevated international normalized ratio values in patients undergoing anticoagulation therapy: a descriptive
Thomas Delate1, Daniel M Witt2, Jared R Jones2
1Clinical Pharmacy Research Team, Kaiser Permanente Colorado, Aurora, CO.
Chest
|March 16, 2007
Summary
Falsely elevated international normalized ratio (INR) values occur infrequently but pose challenges. Patients on hemodialysis are most at risk for falsely high INR results, requiring careful monitoring.
Area of Science:
- Clinical Chemistry
- Pharmacology
- Hematology
Background:
- Elevated international normalized ratio (INR) values are associated with bleeding risks.
- Physiologic INR elevations are not always the cause; falsely elevated INRs can occur.
- Understanding the prevalence and predictors of falsely elevated INRs is crucial for patient safety.
Purpose of the Study:
- To determine the rate of falsely elevated INR values.
- To identify patient characteristics that predict falsely elevated INRs.
- To improve the management of anticoagulation therapy.
Main Methods:
- A cross-sectional study analyzed INR values from adult patients on anticoagulation therapy (2000-2004).
- Prevalence rates of elevated, falsely elevated, and truly elevated INRs were calculated.
- Multivariate logistic regression identified predictors of falsely elevated INRs.
Main Results:
- Falsely elevated INRs occurred in 0.01% of all INR measurements.
- Patients undergoing hemodialysis had a significantly higher risk of falsely elevated INRs (aOR, 9.60).
- A low target INR was another independent predictor of falsely elevated INR values.
Conclusions:
- Infrequent, falsely elevated INR values (> /= 10.0) present a clinical challenge.
- Anticoagulation providers must be vigilant for falsely elevated INRs, especially in hemodialysis patients.
- Awareness of predictors can aid in accurate INR interpretation and patient management.
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