Urine Tests

Doctors order urine tests for kids to make sure that the kidneys and certain other organs are working as they should, or when they think that a child might have an infection in the kidneys, bladder, or other parts of the urinary tract.

The kidneys make urine (pee) as they filter wastes from the bloodstream, while leaving substances in the blood that the body needs, like protein and glucose. So when urine contains glucose, too much protein, or has other irregularities, it can be a sign of a health problem.

Urinalysis

A urinalysis is usually ordered when a doctor suspects that a child has a urinary tract infection (UTI) or a health problem that can cause an abnormality in the urine. This test can measure:

• the presence of red and white blood cells
• the presence of bacteria or other organisms
• the presence of substances, such as glucose, that usually shouldn’t be found in the urine
• the pH, which shows how acidic or basic the urine is
• the concentration of the urine

Sometimes, when the urine contains white blood cells or protein, or the test results seem abnormal for another reason, it’s because of how or when the urine was collected. For example, a dehydrated child may have concentrated (darker) urine or a small amount of protein in the urine. But that might not mean that there’s a health problem. Once the child is rehydrated, these “abnormal” results may disappear. Depending on the amount of protein or other cells in the urine, the doctor may repeat the urine test at another time, just to make sure that everything is back to normal.

How a Urinalysis Is Done

In most cases, urine is collected in a clean container, then a small plastic strip that has patches of chemicals on it (the dipstick) is placed in the urine. The patches change color to indicate things like the presence of white blood cells or glucose.

Next, the doctor or laboratory technologist also usually examines the same urine sample under a microscope to check for other substances that indicate different conditions.

If the dipstick test or the microscopic test shows white blood cells, red blood cells, or bacteria (possible signs of a kidney or bladder infection), the doctor may send the urine to a lab for a urine culture to identify the bacteria that may be causing the infection.

Getting a urine sample. It can be difficult to get urine samples from kids to test for a possible infection. That’s because the skin around the urinary opening (urethra) normally is home to some of the same bacteria that cause UTIs. If these bacteria contaminate the urine, the doctors might not be able to use the sample to tell if there is a true infection or not.

To avoid this, the skin surrounding the urinary opening has to be cleaned and rinsed immediately before the urine is collected. In this “clean-catch” method, the patient (or parent) cleans the skin, the child then urinates, stops momentarily (if the child is old enough to cooperate), then urinates again into the collection container. Catching the urine in “midstream” is the goal.

In some cases (for instance, if a child is not toilet trained), the doctor or nurse will insert a catheter (a narrow, soft tube) through the urinary tract opening into the bladder to get the urine sample. In certain situations, a sterile bag can be placed around a baby’s diaper area to collect a urine sample.

If you have any questions about urine tests, talk with your doctor.