Creatinine is a waste product your kidneys filter out of your blood, so its level is a common way to check how well your kidneys are working. Here is how to read yours.
Creatinine is a waste product made by your muscles during normal activity. Healthy kidneys filter it out of your blood and remove it in urine, so the amount left in your blood reflects how well your kidneys are filtering. It is measured in mg/dL, usually as part of a metabolic panel.
Creatinine levels are affected by muscle mass, age, and sex, so the normal range varies from person to person and lab to lab. A higher creatinine can suggest the kidneys are filtering less effectively. It is often reported alongside eGFR, an estimate of kidney filtration calculated from your creatinine. Your clinician reads them together.
A higher creatinine can point toward reduced kidney function, but it can also be influenced by dehydration, certain medicines, and having more muscle. A single result is a starting point. Your clinician may repeat the test, look at eGFR, and consider your history before drawing conclusions.
Upload your metabolic panel and Mednex reads creatinine and eGFR together in plain language, and tracks them over time.
Decode my labsContent last reviewed 9 July 2026. Reference ranges vary by laboratory; always read your results against the range printed on your own report.
This page explains a common lab marker in general terms using public information from the U.S. National Library of Medicine and other NIH sources. It is educational and is not a diagnosis or medical advice. Reference ranges differ between laboratories and the meaning of a result depends on your age, sex, medications, and overall health. Always discuss your own results with the clinician who ordered them.