Serum or Plasma Creatinine Concentration (Mass Concentration)

Why This Test Matters

Creatinine is a natural byproduct of muscle breakdown and is filtered out of your blood by your kidneys. High levels can indicate poor kidney function, while low levels might suggest dehydration or other conditions. This test is often used alongside other measures, like blood urea nitrogen (BUN), to evaluate kidney health.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications or foods for a short time before testing. If you’re on a low-protein diet or have kidney-related questions, discuss this with your healthcare provider. You’ll typically have a small blood sample drawn from your arm.

What the Results Mean

Results are compared to a reference range based on your age, sex, and overall health. While creatinine levels can vary slightly due to factors like muscle mass or hydration status, consistently high or low levels may signal underlying health concerns that need further investigation.

Common Causes of Abnormal Results

High creatinine levels may be due to kidney disease, dehydration, or conditions affecting muscle metabolism. Low levels can occur with dehydration, overhydration, or certain medications. Your doctor will consider your full medical history and other test results to determine the cause.