What It Is
A microalbumin-to-creatinine ratio urine test involves measuring the amount of
a protein called albumin in the urine (pee). The amount of urine albumin is compared
with the quantity of a waste product in the urine called creatinine.
The body normally filters out creatinine in the urine at a steady rate, so comparing
the ratio of urine albumin with creatinine in the same urine specimen helps determine
if the body is excreting albumin at an increased rate. If this is happening, it may
be the result of kidney disease.
In most healthy people, the kidneys prevent albumin and other proteins from entering
the urine. However, if kidneys are damaged and start to allow proteins to pass from
the blood into the urine, the first type of protein to appear in the urine is albumin.
This is because albumin molecules are smaller than most other protein molecules.
The consistent presence of small amounts of albumin in the urine is called microalbuminuria
and is associated with early-stage kidney disease. Once there are larger amounts of
albumin in the urine it is called macroalbuminuria and it could indicate more severe
kidney disease.
Why It's Done
The microalbumin-to-creatinine ratio test is most commonly used to screen for kidney
problems in teens with diabetes. It also might be done on a more regular basis, like
once a year, in teens with diabetes to help in early identification of kidney disease.
It also can be used to monitor kidney function in kids and teens already diagnosed
with kidney disease or taking medications that can affect the kidneys. The test can
also help detect kidney complications from hypertension and autoimmune diseases.
Preparation
Your child might need to temporarily stop taking specific drugs that could interfere
with test results. Be sure to review all your child's medications with your doctor.
The Procedure
Your child will be asked to urinate (pee) into a clean sample cup in the doctor's
office or at home. Collecting the specimen should only take a few minutes. If your
child isn't potty trained and can't urinate into a cup, a catheter (a narrow, soft
tube) may need to be inserted into the bladder to obtain the urine specimen.
A urine collection bag with adhesive tape on one end might instead be used to collect
a sample from an infant. If you're doing the collection at home, you'll clean your
baby's genital area and then attach the bag around the urinary opening. Once the bag
is in place, you'll secure it with the attached tape. You can put a diaper on your
baby once you've attached the bag. Remove the collection bag after your baby has urinated
into it, usually within an hour. Deliver this specimen to your lab.
Sometimes, a doctor will want to test urine collected over a period of time ranging
from 4 to 24 hours. After each urination, you or your child will pour the specimen
from the sample cup into a larger container. Be careful not to touch the inside of
the container. During the testing period, all the urine should be collected, even
if it is just a small amount.
For specimens collected at home, follow any storage and transportation instructions
the lab gives you. At the lab, the technician will determine the quantity of albumin
in the urine and compare it with the amount of creatinine in the urine.
What to Expect
Because the test involves normal urination, there shouldn't be any discomfort as
long as your child can provide a urine specimen. It's important to keep the area around
the urinary opening clean before the test.
Getting the Results
The results of the microalbumin-to-creatinine test will be available in 1-3 days.
It's important to know that children sometimes pass albumin in their urine even though
they have no kidney damage.
If the test shows abnormal results, further tests will be ordered to determine
if there's an illness and, if so, help diagnose it. Talk to your doctor about the
meaning of the specific test results.
Risks
Collecting a urine sample for the urine microalbumin-to-creatinine ratio test is
usually painless and without risk. Infants may occasionally experience skin irritation
from the adhesive tape on the collection bag. If a catheterized specimen is required
it may cause temporary discomfort.
You can discuss any questions you have about this procedure with your doctor.
Helping Your Child
Explaining in simple terms how the test will be conducted and why it's being done,
can help ease any fear. Make sure your child understands that there should be no foreign
matter, such as toilet paper or hair, in the sample. And all the urine should be collected
during the designated period for the test to be accurate.
If You Have Questions
If you have questions about the microalbumin-to-creatinine ratio test, speak with
your doctor.
