pH Probe Study


A pH probe study is a test that is done to find out if acid from the stomach is coming up into the esophagus (the tube that leads from the mouth to the stomach). This backward movement of food and acid is called gastroesophageal reflux.

What happens during the pH probe?

A GI nurse will check the child’s height to determine where to place the tube. A small flexible tube will then be inserted through the child’s nose and into the stomach. Infants and small children may be bundled in blankets to make them more comfortable, older children may elect to be sitting up while the tube is placed. The passing of the tube may cause the child to cough or gag, this feeling goes away after the tube is in place. A chest x-ray will be done to check that the tube is in the right place. You will be asked to write down certain things your child is doing while the tube is in place such as eating, drinking, coughing, and sneezing. The nurse will give specific directions when the study begins. After 18-24 hours of recording, the tube will be removed.


Your child must have an empty stomach for a pH probe study. Please do not allow your child to eat breakfast. You will be on the children’s unit for the duration of the study. Certain medications should be stopped 72 hours prior to the pH probe study. These include omeprazole (Prilosec), cimetidine (Tagamet), ranitidine (Zantac), metoclopramide (Reglan) Axid, Prevacid, Pepcid, Antacids such as Tums, Maalox, Gelusil.

Checking in at the hospital

Unless otherwise instructed, you will receive a phone call with specific instructions about where and when to arrive at UF Health Shands Hospital for the test. When you arrive on the children’s floor, a GI nurse will greet you and explain the procedure again. Any questions you have will be answered at this time.


Results are usually available about 1 week after the procedure. Please call (352) 273-8381 at this time for the results.