Plasma or Serum Creatinine Concentration (Mass 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 builds up in your blood. This test helps doctors monitor kidney health, especially in people with diabetes, high blood pressure, or other conditions that may affect the kidneys.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood draw (from a vein) or a urine sample (if testing urine creatinine). If you’re on certain medications or have recent kidney-related symptoms, let your healthcare provider know before the test.

What the Results Mean

Results are typically reported in units like milligrams per deciliter (mg/dL) or micromoles per liter (µmol/L). While reference ranges vary by lab, higher than expected levels may signal kidney problems, while very low levels could indicate muscle loss or other conditions. Your doctor will interpret results in the context of your overall health.

Common Causes of Abnormal Results

High creatinine levels may be due to kidney disease, dehydration, or conditions that reduce blood flow to the kidneys. Low levels might occur with severe muscle wasting, liver disease, or certain medications. Other factors, like recent exercise or diet, can temporarily affect results.