Kidney
Creatinine
LOINC 2160-0 · mg/dL
What it is
Creatinine is a waste product from normal muscle activity that the kidneys filter out of the blood. It is a core measure of kidney function.
Why it matters
Because healthy kidneys keep creatinine low, the level is a key window into how well your kidneys are filtering.
What high values can mean
A higher value can indicate reduced kidney function, dehydration or, in some cases, high muscle mass.
What low values can mean
A lower value can relate to low muscle mass and is usually not a concern.
How to improve it
Staying well hydrated and managing blood pressure and blood sugar protect kidney function over time.
Food & lifestyle
Adequate fluids and a balanced diet support the kidneys; very high protein intake is best discussed with a clinician if kidney function is reduced.
Preparing for the test
A blood test, often with a metabolic panel; fasting is not specifically required — follow your lab.
When to talk to a doctor
Discuss a rising or high creatinine with a doctor, who will look at eGFR and your overall picture.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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