What is the normal adult male serum creatinine range?

• A. 0.15–0.5 mg/dL
• B. 2.05–3.0 mg/dL
• C. 0.65–1.2 mg/dL
• D. 1.55–2.5 mg/dL

Answer: (C)

Creatinine comes from muscle metabolism at a fairly constant rate and is cleared by the kidneys; its serum level therefore reflects kidney filtration in people with normal muscle mass. In a healthy adult male, the typical range is about 0.6 to 1.2 mg/dL, reflecting the usual higher muscle mass in men compared with smaller ranges in women or individuals with less muscle. Values much lower than this are uncommon in adults and may occur with very low muscle mass or lab variation, while values above this range suggest reduced kidney function or increased production relative to clearance.