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 build up in your blood. This test is often used to monitor kidney health, especially in people with risk factors like high blood pressure, diabetes, or a family history of kidney disease.

What to Expect During the Test

You’ll typically have a small needle inserted into your arm or vein to draw blood. The test is quick and usually done in a lab setting. If you’re tested for creatinine in urine, you may need to collect a sample over a 24-hour period or provide a random urine sample.

Factors That Can Affect Results

Several factors can influence creatinine levels, including muscle mass (higher muscle mass can lead to higher levels), dehydration, certain medications, or recent exercise. If you’ve had recent surgery, trauma, or changes in diet (like eating more meat), let your healthcare provider know so they can interpret your results accurately.

Common Uses of This Test

Doctors use creatinine tests to diagnose and monitor kidney disease, track how well dialysis is working, evaluate kidney function before surgeries or procedures, and check for conditions like chronic kidney disease (CKD) or acute kidney injury (AKI).