Serum/plasma mass concentration of creatinine

Why This Test Matters

Creatinine levels can indicate how efficiently your kidneys are working. High levels may suggest kidney damage or disease, while low levels might indicate dehydration or other conditions. This test is often used alongside other measures to evaluate kidney health, especially in people with symptoms like fatigue, swelling, or frequent urination.

What to Expect Before the Test

No special preparation is needed for this test. You may have a blood draw from a vein in your arm, or if a urine sample is collected, you’ll likely be asked to provide a midstream urine sample. If your doctor orders a 24-hour urine creatinine test, you’ll need to collect all urine for a full day.

What the Results Mean

Results are typically reported as a mass concentration (e.g., in milligrams per deciliter or micromoles per liter). While reference ranges vary by lab, higher than expected levels may signal impaired kidney function, while lower levels could indicate dehydration or other metabolic issues. Your doctor will interpret results in the context of your overall health and symptoms.

Common Causes of Abnormal Results

High creatinine levels may be linked to kidney disease, dehydration, heart failure, or muscle disorders. Low levels might result from dehydration, overhydration, or certain medications. Other factors, like recent exercise or muscle breakdown, can temporarily affect results.