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Regulatory Focus™ > News Articles > 11 > Warfarin Monitors: FDA Warns of Inaccurate Results

Warfarin Monitors: FDA Warns of Inaccurate Results

Posted 02 November 2018 | By Zachary Brennan 

Warfarin Monitors: FDA Warns of Inaccurate Results

The US Food and Drug Administration on Friday announced a Class I recall, the most serious type of recall, for Roche medical devices that monitor levels of the blood thinner warfarin. FDA is warning that certain test strips used with the devices may provide inaccurate results and should not be relied on to adjust the drug dosage.

Roche Diagnostics issued a voluntary recall of 1.1 million packages of CoaguChek XS PT Test Strip (list of test strip lots). The recall involves packages distributed nationwide from 12 January 2018 to 29 October 2018.

CoaguChek XS PT Test Strips are used with Roche INR Test Meters to monitor patient response to warfarin, and according to FDA, “The test strip is inserted into the test meter, and then a medical pricking needle (a lancet) is used to obtain blood which is applied to the test strip. The meter reads the test strip, measures how long it takes the blood to clot, and provides the result based on a standardized calculation in the form of the International Normalized Ratio, or INR. The INR is used by patients and physicians to determine if warfarin dosing is appropriate.”

Roche Diagnostics attributes the cause of the problem to a recent recalibration of the test strips to a different international standard that occurred earlier this year.

The company also plans to provide new batches of recalibrated test strips, based on the previous international standard, to their customers by the end of November. FDA said it reviewed validation data submitted by the company. The test strips are used with the CoaguChek XS plus, CoaguChek XS Pro, CoaguChek XS professional, CoaguChek XS PST and CoaguChek Vantus test meter devices.

FDA is warning patients and health care professionals that they should not rely on these test meter devices to monitor warfarin levels if they’re using test strips affected by the recall. Instead, they should have blood drawn from a vein and have their levels measured by a laboratory test or use an alternative meter device.

The agency is encouraging all health care providers, patients and caregivers to voluntarily report INR test meter problems through MedWatch, FDA’s voluntary reporting program. “Problems should be reported whenever one suspects that there may be an issue with an INR test meter such as a malfunction or incorrect result, or that the meter caused or contributed to a serious injury or death,” FDA said.

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