Serum or Plasma Creatinine Concentration (Substance Concentration)

Why This Test Matters

Creatinine is a byproduct of muscle breakdown and is normally filtered out by your kidneys. High levels may indicate kidney problems, while low levels could suggest dehydration or muscle loss. This test is often used alongside other kidney function tests to monitor overall kidney health.

What to Expect Before the Test

No special preparation is needed for this test. You may drink water before the test, but avoid excessive fluids unless instructed otherwise. If you’re on a low-protein diet, follow your doctor’s advice, as protein intake can affect creatinine levels.

How the Test Is Performed

A blood sample is drawn from a vein, usually in your arm, using a small needle. You may feel a slight pinch, but it usually doesn’t cause discomfort. The sample is then sent to a lab for analysis.

Possible Results and Interpretation

Results are compared to a reference range that varies by lab and individual factors like age, sex, and muscle mass. Elevated creatinine levels may signal impaired kidney function, while persistently low levels could warrant further investigation for conditions like malnutrition or dehydration.