CREATININE CLEARANCE TEST

The creatinine clearance test is done to determine how well your kidneys are functioning. It compares the level of creatinine, a waste product produced by your muscles, in your blood and urine. This allows the doctor to determine the filtering ability of your kidneys, the glomerular filtration rate (GFR). The test is valuable for identifying early signs of kidney disease and monitoring its progress, or determining how to adjust medications processed by the kidneys.

Process

• The creatinine clearance test is a two-part test that involves a 24-hour urine collection and a single blood draw. 
• You will collect a 24-hour urine sample in a special container.
• You will also need to provide a blood sample either during or immediately after the urine collection. 
• The lab technician will then measure how much creatinine is being cleared from your body.

When to Get Tested

You may need this test if you have any signs of kidney problems, the presence of other disease states (e.g. diabetes or hypertension), or if you need to monitor changes in known kidney disease. The test may also be done to determine if there are potential risks associated with starting new medications.

Sample Type

A 24-hour urine (first passed urine does not need to be collected) sample is required as well as a single blood sample.

Test Preparation

There is no need to fast. However, you should avoid eating any high-protein foods, like red meat, before and during the examination.  You should also tell your doctor any medication you are currently taking. 

Understanding Your Results

Normal values will vary according to age and size of body.  Generally low clearance will mean lesser kidney function. Results should be reviewed with your doctor and they will advise you if any further tests or treatments are necessary.