International normalized ratio (INR) is a system for reporting:

• A. Blood coagulation or clotting
• B. Blood glucose levels
• C. White blood cell count
• D. Renal function

Answer: (A)

INR measures how quickly blood clots. It’s used to standardize prothrombin time so clinicians can reliably monitor and adjust anticoagulant therapy, like warfarin, across different labs. Different labs use different reagents, which can make PT results vary; the INR incorporates the International Sensitivity Index to convert those results into a single, comparable value. This focus on coagulation distinguishes it from tests of glucose, white blood cells, or renal function, which are measured by other specific tests.