Serum or Plasma Creatinine Concentration (Standard Method)

Why This Test Matters

Your kidneys normally filter waste products, including creatinine, from your blood. High levels of creatinine can indicate poor kidney function or damage, while low levels might suggest overhydration or other conditions. This test is often used alongside other measures to monitor kidney health, especially in people with risk factors like diabetes, high blood pressure, or a family history of kidney disease.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into your arm or vein to draw blood. If you’re on a low-protein diet or have recently had contrast dye for imaging, your doctor may advise adjustments. Drinking plenty of water the day before can help dilute creatinine levels if needed.

Common Causes of Abnormal Results

High creatinine levels may signal reduced kidney function, dehydration, or conditions like kidney disease, heart failure, or severe muscle breakdown. Low levels could suggest overhydration, certain medications, or errors in measurement. Your doctor will consider your overall health and other test results to interpret results accurately.

When You Might Need This Test

Doctors order creatinine tests to evaluate kidney function before surgeries, during pregnancy, or if you have symptoms like fatigue, swelling, or frequent urination. It’s also part of routine check-ups for people with chronic conditions like diabetes or high blood pressure.