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. If your kidneys aren’t working well, creatinine levels can build up in your blood. This test is often used alongside other blood tests to evaluate kidney health, especially if you have symptoms like swelling, fatigue, or changes in urine output.

What to Expect During the Test

You’ll have a small needle inserted into your arm or vein to draw blood. The test is quick and usually done in a lab setting. No special preparation is needed unless your doctor instructs otherwise.

How the Results Are Used

Your doctor will compare your creatinine level to a reference range to see if it’s within normal limits. Elevated levels may suggest kidney problems, while lower levels could indicate muscle loss or other conditions. Creatinine is often used in combination with other tests, like blood urea nitrogen (BUN), to assess kidney function more accurately.

Common Causes of Abnormal Results

Creatinine levels can be affected by factors like dehydration, muscle mass, certain medications, or kidney disease. High levels may indicate poor kidney function, while very low levels might suggest dehydration or conditions that reduce muscle mass.