Help & Hope for Kids with Digestive Disorders

Skip to Content

Sublevel Navigation

Connect with Facebook

Our Partners

  • NASPGHAN North American Society for Pediatric Gastroenterology, Hepatology and Nutrition
  • NASPGHAN Foundation North American Society for Pediatric Gastroenterology, Hepatology and Nutrition Foundation
  • APGNN The Association of Pediatric Gastroenterology and Nutrition Nurses
  • Print

pH Probe Study

A pH probe study is a test that measures if acid is coming up from the stomach into the esophagus. The test is used when the doctor suspects the patient has gastroesophageal reflux (GERD) or to determine how effective the treatment is. To learn more about when pH probe study is used and what to expect before and after the test, download the GIKids Fact Sheet on pH Probe Study.

Fact Sheets




What is a pH probe study?

Measuring the pH in the esophagus helps determine whether or not acid is coming up from the stomach.

A pH probe study is usually done in patients where gastroesophageal refulx (GER) is suspected. It is also used to find out how effective treatment is while receiving antacids. In other cases, the study might help explain night time cough, hoarseness or other complaints.

How is the test performed?

A thin, plastic tube with a sensor at the tip is placed into one nostril and advanced into the esophagus. At the time of the placement, this may cause the child to gag, sneeze or make their eyes tear.

A chest x-ray will confirm the position of the tip of teh probe. A wire is connected to a portable recorder that the child can carry around for the duration of the study. The test lasts 18-24 hours.

What is allowed during the test?

The child should continue with usual activities. A diary of symptoms (crying, coughing, chest pain or refusing to eat) helps determine whether acidity in the esophagus is responsible for the child's complaints. Carbonated drinks should be avoided. The recorder should be disconnected if a bath or shower is taken.

What happens after the test?

After 18-24 hours, the tube is removed and the information stored in the recorder is analyzed.

Every downward turn of the curve reflects the presence of acid in the esophagus. A score can be calculated to help determine how abnormal the pH probe study is.

For more information or to locate a pediatric gastroentrologist in your area, please visit the NASPGHAN website.

IMPORTANT REMINDER: This information from the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) is intended only to provide general information and not as a definitive basis for diagnosis or treatment in any particular case. It is very important that you consult your doctor about your specific condition.