Serum or Plasma Creatinine Concentration (Mass Concentration)

Why This Test Matters

Creatinine is a byproduct of muscle activity 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 helps doctors determine if your kidneys are functioning properly or if there may be a problem that needs attention.

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. Your blood will be drawn from a vein, usually in your arm, by a phlebotomist. The process is quick and typically painless.

What the Results Mean

Results are compared to a reference range that varies by age, sex, and overall health. Higher than expected levels may indicate kidney problems, while lower levels could suggest dehydration or muscle loss. Your healthcare provider will discuss your specific results with you.

Common Causes of Abnormal Results

Creatinine levels can be affected by factors such as dehydration, muscle mass, certain medications, or kidney disease. High levels may signal kidney damage, while very low levels might suggest conditions like severe dehydration or muscle wasting.