The manufacturer of the Alere INRatio and INRatio2 PT/INR Monitor system warns this system should not be used to test certain medical conditions. In certain cases an INRatio and INRatio2 PT/INR Monitor system may provide an international normalized ratio (INR) result that is clinically significantly lower than a result obtained using a reference INR system (laboratory method). This issue can arise if the patient has certain medical conditions or can occur if the instructions for performing the test are not followed.
Significant discrepancy in INR results may lead to a delay in an urgent medical decision to reverse an above-therapeutic INR level following the established guidelines for monitoring warfarin therapy. Such discrepancies are of particular concern when the erroneous INR result is within the therapeutic range, but the actual value exceeds the therapeutic, i.e., when the actual INR value is 6 or greater. There may be a serious risk of bleeding.
The Alere INRatio and INRatio2 PT/INR Professional Monitoring System, consisting of the Alere INRatio and INRatio2 PT/INR Monitor and the Alere INRatio Test Strip, is intended for use by health care professionals to quantitatively determine the INR of fresh capillary whole blood to monitor the effect of warfarin, a blood thinner, on clotting time.
The INRatio and INRatio2 PT/INR Monitor system should not be used on patients with anemia of any type with hematocrit less than 30%; any bleeding or unusual bruising, clinically observed or reported by the patient; or with any condition associated with elevated fibrinogen levels. Conditions associated with elevated fibrinogen levels include:
- Acute inflammatory conditions (examples may include acute viral or bacterial infections such as pneumonia or influenza);
- Chronic inflammatory conditions (examples may include rheumatoid arthritis, Crohn’s disease, ulcerative colitis, infectious liver diseases such as hepatitis, or inflammatory kidney diseases such as diabetic nephropathy and glomerulonephritis);
- Severe infection (e.g., sepsis);
- Chronically elevated fibrinogen for any reason;
- Hospitalized or advanced stage cancer or end stage renal disease patients requiring hemodialysis.
Patients with any of the conditions listed above should immediately be transitioned to a laboratory INR method for monitoring their INR and warfarin therapy.
Alere also recommends that all patients have periodic verification of their INR using a laboratory INR method. Any patient having a significantly discrepant low result on the INRatio and INRatio2 monitor system as compared to the plasma-based laboratory INR method should immediately be transitioned to an alternative method for monitoring their INR and warfarin therapy.
Alere also recommends that patients be tested to verify that their hematocrit falls within the range of 30% to 55%. Patients with hematocrit outside this range should be immediately transitioned to a plasma-based laboratory INR monitoring method.
See the Recall
See also Medical Law Perspectives, March 2014 Report: Blood Draws, Testing, Transfusions: Venipuncture Injury, Inaccurate Results, Tainted Blood - The Liability Risks
See also Medical Law Perspectives, December 2013 Report: Thicker Than Water: Liability When Blood Clots Cause Injury or Death
See also Medical Law Perspectives, May 2013 Report: Drugs, Dosage, and Damage: Physician Liability for Prescribing or Administering Medication