Serum Creatinine (Substance Concentration)

Why This Test Matters

Creatinine is a byproduct of muscle metabolism that your kidneys filter out of your blood. High levels may indicate kidney problems, while low levels could suggest dehydration or muscle loss. This test is often used alongside other kidney function tests to monitor overall kidney health, especially in people with diabetes, high blood pressure, or a 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 to draw blood. If you’re dehydrated, your doctor might advise drinking extra fluids the day before. Avoiding certain medications (like NSAIDs) for a few days before testing may also be recommended, depending on your health.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL) or micromoles per liter (µmol/L). While reference ranges vary by lab, higher than expected levels may signal kidney issues, while very low levels might raise concerns about hydration or muscle metabolism. Your doctor will interpret results in the context of your overall health.

Common Causes of Abnormal Results

High creatinine levels can result from kidney disease, dehydration, severe muscle injury, or conditions like heart failure or diabetes. Low levels may occur with dehydration, low muscle mass, or certain liver or heart conditions. Other factors, such as certain medications or diet, can also influence results.