Serum/plasma mass concentration of creatinine (Creatinine Clearance Rate via Serum Creatinine and Urine Volume)

Why This Test Is Done

Your doctor may order this test if you have symptoms like fatigue, swelling, or frequent urination, or if you have a history of kidney disease, diabetes, or high blood pressure. It’s also used before kidney transplants to evaluate baseline kidney function or monitor transplant recipients for complications.

What to Expect Before the Test

You’ll typically provide a 24-hour urine collection (starting and ending at the same time) and a blood sample. Follow your doctor’s instructions carefully to ensure accurate results. Avoid certain medications that may affect kidney function during this period.

How the Test Works

Your urine is collected over 24 hours, and your blood is drawn once. Creatinine levels in your serum and urine are measured to calculate how much waste your kidneys filter daily. This rate helps assess kidney health and identify issues like reduced filtering capacity.

What the Results Mean

Lower than expected clearance may indicate kidney damage or disease, while higher values could suggest dehydration or overhydration. Your doctor will interpret results in relation to your medical history and other tests.