Creatinine is a chemical waste molecule that is generated from normal muscle metabolism. Measurement of this is an indicator of the levels of other waste products in the body. Creatinine is also an accurate marker of kidney function, and may help in diagnosing kidney disease.
What might a low result mean?
Low creatinine can be found in individuals with a low protein diet or reduced muscle mass.
It may also simply indicate that the kidneys are functioning efficiently.
What might a high result mean?
Elevated creatinine can suggest that the kidneys are not functioning properly, and so are not excreting sufficient amounts of creatinine. This may occur in conditions such as glomerulonephritis or bacterial kidney infections. Additionally, dehydration and atherosclerosis can reduce the blood flow to the kidneys and cause this to happen.
For most people the estimated glomerular filtration rate (eGFR) will give a better estimate of kidney function.
Elevated levels may also be found in individuals taking creatinine supplements and engaging in vigorous exercise.