Serum or Plasma Creatinine Concentration (Mass Concentration)

Why This Test Matters

Creatinine is a byproduct of muscle breakdown and is normally filtered out of your blood by your kidneys. If your kidneys aren’t working well, creatinine levels can rise. This test is often used to monitor kidney health, especially in people with 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 may affect results. Avoid strenuous activity the day before.

What Happens During the Test

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but the procedure takes only a few minutes. The sample is then sent to a lab for analysis.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). Higher than expected levels may indicate kidney problems, while lower levels could suggest muscle breakdown or other conditions. Your doctor will interpret results in the context of your overall health.