What is a creatinine test?

Creatinine is a waste product produced by your muscles during daily activities. Normally, your kidneys filter creatinine from your blood and excrete it naturally from your body. If there are kidney problems, creatinine can accumulate in the blood and be excreted to a lesser extent in the urine. If the level is not normal, it may be a sign of kidney disease.

With a creatinine test, you can check if your kidneys are working properly. It is often ordered along with another kidney test called blood urea nitrogen (BUN) or as part of a comprehensive metabolic panel (CMP). CMP is a group of tests that provide information about various organs and systems of the body.

You may need this test if you have symptoms of kidney disease such as:

- Fatigue

- Swelling around the eyes

- Swelling of the legs and/or ankles

- Decreased appetite

- Frequent and painful urination

This test should also be done if you have certain risk factors for kidney disease, including type 1 or type 2 diabetes, high blood pressure, and a family history of kidney disease.