Plasma or Serum Creatinine Concentration (Substance Concentration)

Why This Test Matters

Creatinine is a byproduct of muscle breakdown and is filtered out of your blood by your kidneys. If your kidneys aren’t working properly, creatinine builds up in your blood. This test helps doctors monitor kidney health, especially in people with conditions like diabetes, high blood pressure, or those taking certain medications that can affect kidney function.

What to Expect Before the Test

You may be asked to fast for a few hours before the test, but this isn’t always required. A healthcare provider will draw blood from a vein in your arm. The process is quick and usually painless. If you’re on dialysis, your doctor may schedule this test during your treatment.

What the Results Mean

Results are compared to a reference range that varies by lab and age. Higher levels may indicate kidney problems, while lower levels could suggest muscle loss or other conditions. Your doctor will interpret the results in the context of your overall health.

Common Causes of Abnormal Results

High creatinine levels can be caused by kidney disease, dehydration, severe muscle damage, or conditions that reduce blood flow to the kidneys. Low levels may be linked to muscle atrophy, liver disease, or certain medications.