microINR System

The microINR System is a handheld point-of-care device that measures prothrombin time (PT) expressed as International Normalized Ratio (INR) to monitor warfarin therapy. It uses fresh capillary blood from a fingerstick applied to disposable test chips and is intended for both patient self-testing and healthcare professional use in patients 18 years or older who are stable on warfarin for at least 6 weeks.

The device maintains unchanged hardware design and fundamental microfluidic technology with machine vision detection compared to predicates K243543 and K180780. Only software changes were implemented to expand the INR measurement range from 4.5 to 8.0 and remove the exclusion limitation for LVAD patients. All other system components—chip design, reagent composition, calibration method, and quality control mechanisms—remain identical.

Not stated in this summary. The document references no specific ISO, IEC, or ASTM consensus standards. It notes that calibration traces to World Health Organization International Reference Thromboplastin but does not cite formally designated test standards.

The device is substantially equivalent because it uses the identical microfluidic test principle, hardware design, and reagent chemistry as the predicate devices with only software modifications to expand measurable range. Performance data demonstrates maintained accuracy (Pearson r=0.97 vs. laboratory reference, slope 1.00) and precision (CV 4.6–5.0%) across the extended INR range up to 8.0, including in untrained self-testers with high values. Since the technological characteristics, intended use, and test principle remain fundamentally unchanged and performance is validated across the new patient populations, no new safety or effectiveness questions are introduced.