What it is
This test measures how well your kidneys are working. Creatinine is a protein that is removed from the blood by the kidneys. Measuring the speed at which that happens (the clearance rate) gives the doctor a good idea of how well your kidneys are functioning. To perform the test, your urine will be collected in a container for 24 hours. Then, the creatinine will be measured in both the urine and blood, and the creatinine clearance calculated using a mathematical formula. The urine must be stored in a dark bottle or covered with a dark cloth, and be kept either in the refrigerator or on ice.
Getting ready
- This test does not hurt.
- Remember to collect all of your urine for 24 hours.
- You should always feel free to ask any questions about what is going to happen before any procedure. Knowing what will happen will help you feel more comfortable, and less anxious.