A nurse is reviewing laboratory findings of a client admitted to the unit. The nurse recognizes that which of the following results indicates acute kidney injury?

A. Hemoglobin 16 g/dL: This value is within the normal range—approximately 13.5 to 17.5 g/dL for males and 12 to 16 g/dL for females. It reflects adequate oxygen-carrying capacity and does not suggest acute kidney injury. B. Serum creatinine 6 mg/dL: The normal range for serum creatinine is about 0.6 to 1.2 mg/dL. A level of 6 mg/dL is significantly elevated and indicates reduced glomerular filtration, which is a key diagnostic marker for acute kidney injury. C. BUN 15 mg/dL: Blood urea nitrogen (BUN) typically ranges from 7 to 20 mg/dL. This value is normal and does not indicate renal dysfunction on its own, though it may be elevated in AKI when paired with high creatinine. D. Serum potassium 4.5 mEq/L: Normal potassium levels range from 3.5 to 5.0 mEq/L. This value is within normal limits and does not reflect the electrolyte disturbances commonly seen in acute kidney injury.