Creatinine Levels: What Your Result Means

Creatinine is a waste product from normal muscle activity that healthy kidneys filter out of the blood. A creatinine blood test (serum creatinine) is one of the most common ways doctors check kidney function, often alongside calculating your eGFR.

Normal creatinine level ranges

Typical reference ranges (these vary by lab):

• Adult men: approximately 0.7–1.3 mg/dL
• Adult women: approximately 0.6–1.1 mg/dL

Muscle mass, age, sex, hydration, and diet all affect creatinine, so always compare your result against the reference range printed on your own lab report, not a generic chart. A muscular person can have a higher baseline creatinine without any kidney problem.

What does a high creatinine level mean?

A creatinine level above your lab's normal range can suggest reduced kidney filtration, but it can also be temporarily raised by dehydration, intense exercise, certain medications, or a high-protein meal shortly before testing. A single high result is usually followed up with a repeat test and an eGFR calculation, not treated as a definitive diagnosis on its own.

What actually affects creatinine (and what to ask about)

There's no single food or supplement that reliably "prevents" or "lowers" creatinine on its own, and reducing protein intake without medical guidance can cause other nutritional problems. Any dietary change aimed at your creatinine or kidney results should be planned with a renal dietitian or your doctor, based on your actual test results rather than the number alone. Things that can genuinely affect a creatinine result include:

• Hydration status at the time of the test
• Recent intense exercise or muscle breakdown
• Certain medications (ask your doctor or pharmacist about yours specifically)
• Underlying kidney function itself

Creatinine and eGFR

Creatinine is one input used to calculate eGFR, which is the number doctors actually use for CKD staging. Use our free GFR calculator to see what your creatinine result translates to, and read our CKD stages guide for what that number means.