Serum Creatinine (Creatinine)

Why This Test Matters: This test gives your healthcare provider important information about your health, helping to detect problems early, guide treatment decisions, and monitor how well your current care plan is working over time.

Creatinine levels can indicate how well your kidneys are working. High levels may suggest kidney damage or disease, while low levels could indicate muscle loss or other conditions. This test is often used alongside other kidney function tests to monitor overall kidney health.

What to Expect Before the Test: Your healthcare team will explain how to prepare, including whether you need to fast, adjust or stop certain medications, and whether you should arrange for someone to drive you home afterward.

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on a low-protein diet or have recently exercised, your results might be affected, so it’s best to discuss this with your healthcare provider.

How the Test Works: During the test, a trained healthcare professional will perform a carefully controlled procedure that usually takes only a short time, and the information or samples collected will be analyzed to create accurate results for your provider.

Creatinine is produced when your muscles break down proteins. Your kidneys filter this waste from your blood. If your kidneys aren’t working well, creatinine builds up in your blood at higher levels. This test measures the concentration of creatinine in your serum.

Common Reasons for Testing: Your provider may order this test to check for signs of illness, confirm or rule out a diagnosis, evaluate symptoms you have been experiencing, or track an existing condition to see how it is changing over time.

Doctors may order a creatinine test if you have symptoms like swelling, fatigue, or changes in urine output. It’s also used to monitor kidney function in people with diabetes, high blood pressure, or a history of kidney problems.