The INRatio device by Alere Inc. is at the heart of the litigation over the highly contested blood thinner, Xarelto. The device is now the subject of its own lawsuit, alleging the device is defective in design and manufacture.

The INRatio is a blood monitoring device used in conjunction with the traditional blood thinner Warfarin. The INRatio measures a patient’s prothrombin time (PT), or the time it takes for a patient’s blood to clot. Patients taking Warfarin need to stay within a certain range to ensure they are minimizing their risk of blood clots without exposing themselves to a higher risk of uncontrollable bleeding.

In 2014, Alere recalled the INRatio after it was discovered the device was giving false readings up to 30% of the time. The company worked hard to improve the device, but this past summer the FDA advised the company to recall the second generation of the device, the INRatio 2, because the device was still providing inaccurate readings.

Because erroneous readings could have disastrous and potentially fatal consequences for patients, lawsuits are being filed around the country against Alere claiming the company put patients at extreme risk with its device.

But the INRatio is also in hot water for the part it played in the clinical trials eventually leading to Xarelto’s approval. Xarelto manufacturer Janssen Pharmaceuticals used the INRatio in its clinical trials to compare Xarelto’s effectiveness to Warfarin. Plaintiffs believe the faulty device compromised the clinical trial data and that Xarelto should be recalled from the market while more conclusive trials are conducted.

The first cases in the Xarelto litigation are set to go to trial in early 2017, and the INRatio will be at the center of these lawsuits. The outcome of the Xarelto trials could make Alere decide to settle its own cases rather than take them to court.