A nurse is reviewing the pre-procedure instructions for a patient undergoing an elective angiogram to evaluate their coronary arteries. It is essential for the nurse to ensure that the patient has followed the necessary preparation steps to minimize risks and complications associated with the procedure. One critical aspect of the preparation involves ensuring that the patient's serum creatinine levels are within an acceptable range, as elevated serum creatinine levels can indicate impaired renal function. The nurse must verify that the patient's serum creatinine level is no higher than ________ mg/dL before proceeding with the angiogram.