Elevated creatinine serum what is critical?

Diagnosis needed. Serum creatinine is affected by protein intake, gender, age, race, muscular build, and renal function. A rising creatinine is always of concern. "normal" on lab tests is generally less than 1.2 mg/dl. Renal function can be estimated with a more complex formula or measured with a 24 h urine collection. See your internist for further evaluation.