Serum or plasma concentration of **creatinine** (mass concentration)

What Does This Test Measure?

Creatinine is a byproduct of muscle breakdown and is normally filtered out by your kidneys. Elevated levels may indicate reduced kidney function or other health concerns. This test is often used alongside other kidney function tests, such as blood urea nitrogen (BUN), to evaluate kidney health.

Why Might You Need This Test?

Your healthcare provider may order a creatinine test to monitor kidney disease, diagnose conditions like kidney failure, or evaluate symptoms such as swelling, fatigue, or changes in urine output. It can also be used before surgeries or treatments that may affect kidney function.

How Is the Test Performed?

For a blood test, a small sample of blood is drawn from a vein, usually in your arm. For a urine test, you may collect a sample over a 24-hour period or provide a single random sample. The sample is then sent to a lab for analysis.

What Are Common Results?

Results are typically reported in units of milligrams per deciliter (mg/dL) for blood or milligrams per gram (mg/g) for urine. While reference ranges vary by lab, higher than expected levels may signal kidney issues, while lower levels could indicate dehydration or muscle loss.