A nurse is reviewing the laboratory results of a client who is receiving gentamicin for staphylococcus. Which of the following findings should the nurse report to the provider immediately?

The correct answer is D: Creatinine 1.8 mg/dL. Elevated creatinine levels indicate potential kidney damage, a known side effect of gentamicin. The nurse should report this immediately to prevent further renal impairment. A: Fasting blood glucose of 130 mg/dL is slightly elevated but not a priority over kidney function. B: WBC 11,000/mm┬│ is within normal range and not directly related to gentamicin therapy. C: Potassium 4.5 mEq/L is also within normal limits and not a concerning finding in this context.