What Is a Creatinine Blood Test?

Creatinine is a waste product from muscle that your kidneys filter. It is the key marker of kidney function.

Normal Range

• Men: 0.7–1.3 mg/dL
• Women: 0.6–1.1 mg/dL

High Creatinine

• Chronic kidney disease
• Dehydration
• NSAIDs
• High muscle mass (not kidney disease)
• Urinary obstruction

Low Creatinine

• Low muscle mass
• Pregnancy
• Liver disease

Relationship to eGFR

• eGFR is calculated from creatinine + age + sex
• Always interpret creatinine with eGFR
• A creatinine of 1.2 may be normal for a bodybuilder but abnormal for an elderly woman