Serum Creatinine (Creatinine Level)

Why This Test Matters

Creatinine is a byproduct of muscle breakdown and is normally filtered out of your blood by your kidneys. High levels can indicate poor kidney function, while low levels may suggest dehydration or other conditions. This test is often used alongside other kidney function tests to diagnose or monitor kidney disease.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on a low-protein diet or have recently exercised heavily, your doctor may advise timing your test around it to get the most accurate results.

Common Causes of Abnormal Results

High creatinine levels may signal kidney problems, such as chronic kidney disease, acute kidney injury, or conditions that reduce blood flow to the kidneys (e.g., severe dehydration, heart failure). Low levels might indicate dehydration, overhydration, or conditions affecting muscle mass (e.g., malnutrition). Other factors, like recent muscle damage or certain medications, can also influence results.

When This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like fatigue, swelling, frequent urination, or changes in urine appearance. It’s also used during pregnancy, before surgeries, or to monitor chronic conditions like diabetes or heart disease.