How is a creatinine blood test performed?

A creatinine test is a simple blood test. A healthcare professional will draw a small sample of blood, typically from a vein in your arm. The sample is then sent to a laboratory for analysis. In some cases, your doctor might request a creatinine clearance test, which also involves a 24-hour urine collection to compare blood and urine creatinine levels. Both tests help evaluate how efficiently your kidneys are filtering creatinine and other waste products from your body.