A nurse on a medical unit is reviewing the laboratory reports for a client. Which of the following laboratory values is the priority to report to the provider?

A. A potassium level of 3 mEq/L indicates hypokalemia, as the normal serum potassium range is approximately 3.5–5 mEq/L. Potassium is critical for cardiac, neuromuscular, and muscular function, and low levels can lead to life-threatening cardiac arrhythmias, including ventricular tachycardia or fibrillation. Additional manifestations may include muscle weakness, cramping, fatigue, and in severe cases, respiratory muscle impairment. Because hypokalemia has immediate potential for severe complications, it is the priority value to report to the provider to initiate timely interventions such as potassium supplementation or adjustment of medications that may be causing potassium loss (e.g., diuretics). B. A creatinine value below the normal range (0.6–1.3 mg/dL) is usually not acutely dangerous. Low creatinine can occur due to decreased muscle mass, malnutrition, or overhydration. While it may require monitoring or consideration in medication dosing, it does not pose an immediate life-threatening risk. C. A sodium level of 135 mEq/L is at the lower end of the normal range (135–145 mEq/L) and typically does not require urgent action. Mild hyponatremia can be monitored and addressed as needed, but it is not as critical as hypokalemia. D. This value is within the normal range (7–20 mg/dL) and does not indicate acute kidney dysfunction or pose an immediate health risk.