Reference range for creatinine using the Jaffe method in males?

• A. 0.9-1.3 mg/dL
• B. 0.6-1.1 mg/dL
• C. 0.5-0.8 mg/dL
• D. 1.0-1.5 mg/dL

Answer: (A)

Creatinine is produced at a relatively constant rate from muscle and is cleared by the kidneys, so the reference interval reflects normal renal function in adults. When the traditional Jaffe colorimetric assay is used, the commonly cited reference range for adult males is about 0.9–1.3 mg/dL. This range accounts for typical muscle mass and renal clearance in healthy men, acknowledging that the Jaffe method can be influenced by substances that slightly alter the measurement. Values outside this range may suggest altered kidney function or other factors affecting creatinine production or excretion. For context, females typically have a lower range, around 0.6–1.1 mg/dL, due to generally lower muscle mass.