Serum Creatinine (Creatinine)

Why This Test Matters

Creatinine levels can indicate how well your kidneys are working. High levels may suggest kidney problems, while low levels might raise concerns about muscle breakdown or fluid overload. Your doctor may order this test to monitor kidney health, especially if you have conditions like diabetes, high blood pressure, or a history of kidney disease.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader metabolic panel. Bring any medications you’re currently taking, as some (like NSAIDs or certain diuretics) can affect results.

How the Test Works

A blood sample is drawn from a vein, typically in your arm. The sample is sent to a lab where creatinine levels are measured using a method like enzymatic analysis or spectrophotometry to detect waste products in your blood.

What the Results Mean

Results are compared to a reference range that varies by age, sex, and muscle mass. Abnormally high levels may signal kidney dysfunction, while very low levels could indicate dehydration, muscle loss, or other conditions. Your doctor will interpret results in the context of your overall health.