What is the Creatinine Clearance Test?
The creatinine clearance test measures how well your kidneys are filtering waste products from your blood. It assesses kidney function by comparing the amount of creatinine in your blood and urine.
The test involves a two-part process:
- 24-Hour Urine Collection: You'll collect all your urine over a 24-hour period in a special container. This provides a complete picture of your creatinine excretion.
- Blood Sample: A blood sample is drawn to measure your blood creatinine level. This shows the amount of creatinine circulating in your system.
Your healthcare provider uses both the urine and blood samples to calculate your creatinine clearance rate. This rate indicates how efficiently your kidneys are removing creatinine, a waste product created during muscle metabolism. A lower creatinine clearance indicates potentially impaired kidney function. Multiple sources confirm the use of both urine and blood samples for this test. Cleveland Clinic, Mount Sinai, Mayo Clinic, and many others detail this process.
Why is the Test Performed?
Doctors order creatinine clearance tests to:
- Assess kidney function.
- Monitor kidney disease progression.
- Evaluate the effectiveness of kidney treatments.
- Determine the appropriate dosage of medications that are processed by the kidneys.
Interpreting Results
The results are expressed as the volume of blood cleared of creatinine per minute or per 24 hours. A lower than normal creatinine clearance indicates that your kidneys may not be functioning properly. It is crucial to discuss your results with your healthcare provider for proper interpretation and to understand what they mean for your overall health. The interpretation requires clinical judgment and cannot be easily summarized here.
