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Creatinine tests measure the level of the waste product creatinine (say "kree-AT-uh-neen") in your blood and urine. These tests show how well your kidneys are working. Blood creatinine level can also be used to calculate the estimated Glomerular Filtration Rate (eGFR).
When the kidneys are not working well, they can't filter creatinine from the blood. So the level of creatinine in the blood goes up. The creatinine clearance (a test that measures how well your kidneys remove creatinine) goes down.
A blood creatinine level or a creatinine clearance test is done to:
You may be asked to:
If you are asked to collect urine, your doctor will give you a large container that holds about 4 L (1 gal). You will use the container to collect your urine for 24 hours.
Tell your doctor ALL the medicines and natural health products you take. Some may affect the results of the test. Your doctor will tell you if you should stop taking any of them before the test and how soon to do it.
For the urine tests
You collect your urine for a period of time, such as over 4 or 24 hours. Your doctor will give you a large container that holds about 4 L (1 gal). You will use the container to collect your urine.
But don't save this urine. Write down the time you began.
Each time you urinate during this time period, collect your urine in a small, clean container. Then pour the urine into the large container. Don't touch the inside of either container with your fingers.
Add this urine to the large container. Then write down the time.
For the blood test A health professional takes a sample of your blood.
The urine test will take 24 hours. The blood test will take a few minutes.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.
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Adaptation Date: 5/5/2021
Adapted By: Alberta Health Services
Adaptation Reviewed By: Alberta Health Services
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