The INRatio Monitor is a handheld device that is used by patients on warfarin, a blood-thinning drug that prevents blood clots.
Patients must frequently check blood-clotting times so they can adjust the dose. Accuracy is extremely important. Patients could have a stroke if they take too little warfarin, or bleed to death if they take too much.
Problems with inaccurately low readings have been known for over a decade. In 2005 and 2006, the FDA issued warnings to the device’s manufacturer for failing to act on complaints about erroneous results.
Yet it was not until December 2014 that Alere issued a Class I recall for INRatio Test Strips, reporting three deaths and nearly 19,000 complaints since 2013. The entire system — including INRatio and INRatio2 Monitors — were recalled in July 2016.
INRatio has now been linked to over 1,451 injury reports since it was approved in 2002. False readings were also linked to 18 deaths in 2014 and 2015.
Adding to the controversy, INRatio Monitors were used in a major clinical trial comparing warfarin to the new blood-thinner Xarelto. Critics say false readings may have skewed results against warfarin.
Earlier this year, FDA investigators concluded that the faulty devices had a “minimal” impact. The Xarelto trial was led by Dr. Robert M. Califf, now head of the FDA.
Source: FDA