The nurse reviews the laboratory results for 4 assigned clients. Which result is most important for the nurse to report to the primary health care provider?
1. Client with atrial fibrillation receiving warfarin for 7 days with an International Normalized Ratio (INR) of 1.3
2. Client with chronic bronchitis who has a hematocrit of 56% [0.56] and hemoglobin of 19 g/dL (190 g/L)
3. Client with Clostridium difficile infection who has a white blood cell count of 15,000/mm3 (15 × 109/L)
4. Client with sepsis receiving gentamycin who has a creatinine of 0.6 mg/dL (53 µmol/L)