Over 1,000 injuries, 35% accuracy, and still for sale: FDA questioned over INRatio blood-testing device

For the second time in less than six months, the Food and Drug Administration (FDA) is being questioned on its ability to regulate the safety of medical devices. Many are asking why the agency has allowed the INRatio monitor, a blood-testing device, to remain on the market after thousands of malfunctions and injuries reports.

INRatio and its updated model INRatio2, came on the market in 2002 as a quick, on-the-spot way to test patients’ blood clotting ability. Specifically, the device is used for patients prescribed warfarin to determine the proper dosage of the drug. Warfarin is a blood-thinner and a wrong dosage poses severe risks. Too little and a blood clot can block an artery to the brain and cause a stroke. Too much and a patient can bleed to death.

Since INRatio came on the market, there have been 9,469 reports of malfunctions sent to the FDA and 1,445 injury reports. Issues with the device were noticed as early as 2005 and 2006, with the FDA issuing two warning letters claiming the device manufacturers had failed to respond to complaints about device errors.

In 2007, a study done in London found that INRatio results only matched with the results of conventional testing 54.2% of the time. INRatio’s numbers have only grown worse, according to a study done by the European Medicines Agency (EMA) on a warfarin alternative, Xarelto. An EMA study released in February discovered serious issues in using INRatio, stating that, “discrepancies of potential clinical relevance were rather frequently observed (approximately in 35% of the estimations).”

Meanwhile, leading competitor CoaguChek was shown to be accurate 74% of the time during the 2007 study, and has only received 95 injury reports since 2002.

Neither the FDA or manufacturer Alere have publicly stated that INRatio malfunctions.  Nor has there been a product recall, with INRatio still being sold on the market as of writing. Several have criticized the FDA for slow action and improper monitoring of medical devices after they’ve been first approved.

Alere says they are working to improve its device, and the FDA is holding a public workshop on March 18 to discuss the accuracy of INRatio and similar devices.