Creatinine clearance test

Creatinine clearance test is a medical procedure used to measure the kidney's efficiency in removing creatinine from the blood. Creatinine is a waste product produced by the normal wear and tear of muscle tissue. The test is often used to diagnose and monitor kidney disease.

Overview

The creatinine clearance test measures the rate at which creatinine is cleared from the blood by the kidneys. This is done by comparing the concentration of creatinine in the urine with the concentration of creatinine in the blood. The test is often used to estimate the Glomerular filtration rate (GFR), which is a measure of how well the kidneys are filtering wastes from the blood.

Procedure

The creatinine clearance test usually involves collecting urine over a 24-hour period. The patient is instructed to urinate into a special container, which is kept refrigerated between collections. At the end of the 24-hour period, a blood sample is also taken to measure the amount of creatinine in the blood.

Interpretation

The results of the creatinine clearance test are usually reported in milliliters per minute (mL/min). A normal creatinine clearance for healthy women is 88-128 mL/min, and for healthy men, it is 97-137 mL/min. Lower than normal creatinine clearance may indicate that the kidneys are not working properly. Other conditions such as kidney failure, chronic kidney disease, and urinary tract obstruction can also cause low creatinine clearance.

Limitations

While the creatinine clearance test is a useful tool in diagnosing kidney disease, it has some limitations. For example, it can be influenced by factors such as diet and muscle mass. In addition, the test requires a 24-hour urine collection, which can be inconvenient for the patient.

See also

• Kidney function test
• Renal physiology
• Chronic kidney disease