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Urine Test: Creatinine

What Is a Urine Test?

Testing a urine sample can help doctors find out what's going on when someone has an infection or other problem in kidneys, bladder, or other parts of the urinary tract.

To help your child get ready for a urine test, find out if they need to avoid any specific foods or activity before the test, or should stop taking any medicines.

Urine tests are painless. To help ease any fears, explain in simple terms how the test is done and why it's needed. Make sure your child understands that the urinary opening (urethra) must be cleaned as instructed and the pee must be collected midstream. Things like toilet paper or hair must not get in the sample.

What Is a Urine Creatinine Test?

Creatinine (kree-AT-eh-neen) is a waste product our muscles make at a steady rate during normal daily activity. The bloodstream carries creatinine to the kidneys, which filter it out of the blood. Then, creatinine passes out of the body in urine (pee). A urine creatinine test measures the amount of creatinine in the urine.

Why Are Urine Creatinine Tests Done?

Healthy kidneys filter the blood to rid it of waste products that the body can't use. Low levels of creatinine in the urine may point to a kidney disease or another condition affecting the kidneys or urinary tract.

A urine creatinine test might be done on a single urine sample or by measuring creatinine in a 24-hour collection of urine. Doctors often do the test along with a blood test to measure the creatinine level in the blood to get information about how well the kidneys are working.

How Is the Test Done?

For a 24-hour creatinine test, you'll collect all the pee your child passes over 24 hours. To do this at home, you’ll get a special container from the lab in which to collect the urine, plus instructions.

If your child isn't potty trained and can't pee into a cup, you might use urine collection bags with adhesive tape on one end to collect the samples. Clean the skin around the urinary opening (the urethra), then place the bag around it and secure with the attached tape. Your child can wear a diaper over the bag. Change the bags often to collect all the pee, and empty the bags into the special container.

Sometimes, doctors might insert a catheter (a narrow, soft tube) into the child’s bladder and leave it there for 24 hours to get a urine collection.

If you collect the sample at home, follow any storage and transportation instructions the lab gives you.

What if I Have Questions?

If you have questions about the urine creatinine test, talk to your doctor.