Collecting a urine sample by puncture from a child

What is it about ?

To diagnose a urinary tract infection, bacteria that can cause an infection (pathogenic bacteria) are cultivated in the laboratory from a fresh urine sample. To do this, the laboratory needs a good quality urine sample. That is, a sample that is not contaminated with bacteria from the skin and / or genitals.

Adults are therefore asked to take a urine sample at mid-stream: the person first urinates a little in the toilet bowl, then a little in the urine container, then again in the toilet bowl.

It is impossible to ask this of a little child. To collect urine from a small child, a urine bag is used. However, this method carries a high risk of contamination of the sample with bacteria from the skin, and even stool. If it is necessary to exclude a urinary tract infection In a small child, the doctor must take a urine sample directly from the bladder, using a needle that he pushes through the wall of the belly (abdominal wall). In Belgium, this puncture is always performed in hospital.

What does the doctor ?

The doctor prepares all the equipment in advance and puts the child’s skin to sleep (anesthesia) with an anesthetic ointment or gel which must act for half an hour.

To be able to puncture the child’s bladder safely, it is important that it is full. The doctor tries to feel it and sometimes uses aultrasound to locate the bladder accurately. The child should continue to drink while waiting. Usually, it is enough to wait half an hour after the last pee.

If the child begins to urinate spontaneously when the doctor presses on his tummy, the doctor can collect this sample “on the fly”. This sample is also generally of good quality.

If the doctor still has to prick through the abdominal wall, the child is held on his back, legs outstretched, by a calm adult. The doctor disinfects the skin and stings just above the pubis, in the bladder. He only needs to draw 10-15 ml of urine into the syringe.

After removing the needle, the doctor covers the puncture site with a bandage. If the doctor has not been able to take a urine sample, he or she may try again after 30 minutes.

The doctor then sends the urine to the laboratory for testing. culture.

Want to know more?

• Distract my child during a treatment, an examination – Plaster

Source

Foreign clinical practice guide ‘urine sampling by bladder puncture in children’ (2000), updated on 03.01.2017 and adapted to the Belgian context on 23.11.2019 – ebpracticenet