Creatinine

Understanding the marker

Creatinine is produced during normal muscle activity and removed from the blood by the kidneys. Its level helps estimate kidney filtering, with muscle mass and other factors taken into account.

Creatinine is used to estimate kidney filtration with an age- and sex-dependent equation. Muscle mass, meat intake, creatine supplements and some medicines can affect it. Interpret the laboratory-reported eGFR when available; assessment for chronic kidney disease also includes urine albumin and persistence over time.

What does high Creatinine mean?

A high creatinine result may reflect reduced kidney filtering, but muscle-related factors and some medicines can also affect it. The estimated filtration rate, called eGFR, and changes over time help determine its meaning.

What does low Creatinine mean?

A low creatinine level can reflect lower production from muscle. Muscle mass, nutrition and previous results help explain it. The value alone is not a complete measure of kidney function.