24-hour pH-Impedance Testing

A process called 24-hour pH impedance testing measures the amount of acid reflux in the esophagus over the course of 24 hours.


One technique your doctor can employ to assess acid and non-acid reflux from your stomach into your oesophagus (the tube that connects your mouth and stomach) during the course of a day is 24-hour pH impedance testing.


Your nose will be punctured, and a thin, flexible catheter (tube) will be inserted and directed into the stomach's hole. Along its whole length, the catheter is able to detect variations in acidity. The catheter transmits data about your acid reflux activities to a computer that you wear on your belt and is roughly the size of a smartphone.


While you eat, drink, sleep, and go about your daily activities, the tube remains in place for the full 24 hours. Your esophagus's other functions and acid levels can be monitored by the doctor during the course of a day.

GERD Diagnosis and 24-hour pH Impedance Testing

Twenty-four-hour pH impedance testing can be used to check for gastroesophageal reflux disease (GERD), a problem with stomach acid backing up into your esophagus. GERD can cause symptoms such as:

  • Heartburn
  • Difficulty swallowing
  • Hoarseness or voice changes
  • Persistent cough or throat-clearing

The test is one of several ways your doctor can test you for GERD and other health problems affecting your esophagus or stomach.


There are several ways GERD can be treated. Diet and lifestyle changes are often sufficient. However, sometimes medications and even surgery are necessary. It is safer and more cost effective to test patients early, provide the right therapy and avoid unnecessary treatment and side effects. Twenty-four-hour pH impedance testing is a tool that can help do that.

How do I prepare?

Your doctor will discuss your medications with you and let you know if and when you should stop taking any of them before your test.


You will be asked to stop eating and drinking four hours before your test is scheduled. Once the catheter is in place, you can eat and drink as you normally would.


The procedure takes between 10 and 30 minutes. It does not require any anesthesia or sedation, so you will be able to return to your regular activities right away.


Twenty-four-hour pH impedance testing is safe and easy for most people. Some people may not be able to tolerate the test due to a sensitive gag reflex. You may also experience mild irritation at the back of the throat from the catheter. In extremely rare events, the esophagus can be torn or otherwise damaged by the procedure.

Alternatives to 24-hour pH Impedance Testing

Other options for assessing the esophagus include an endoscopy procedure called an esophagogastroduodenoscopy, or EGD, which is more comprehensive. It examines the esophagus, stomach and duodenum (the part of the small intestine that is closest to the stomach). An EGD requires sedating medication.

24-hour pH Impedance Testing: What happens?

  1. You will not need any anesthesia or sedation, so you will be awake and alert throughout the procedure.
  2. The doctor sprays some numbing medication into your nose and throat so you are comfortable during insertion of the catheter.
  3. Your procedure starts by measuring the distance from your nose to the opening of your stomach using a manometry catheter.
  4. The doctor puts the end of the testing catheter into your nose. As you swallow with sips of water, he or she guides the catheter down to the opening of your stomach.
  5. Once the catheter is in place, the doctor secures the other end to your face with tape, and loops the catheter over your ear.
  6. You wear a small computer on a belt. The computer is about the size of a smartphone. It picks up information from the acid-sensitive tip of the catheter inside your body.
  7. You can leave the office and go about your day, eating and drinking as you normally would. The catheter should not bother you you will be able to breathe, eat, drink and talk with it in place.
  8. Your doctor may ask you to keep a diary of your meals and activities, and any symptoms you experience.
  9. The catheter records levels of acid refluxing into your esophagus. It transmits this information to the computer and correlates it to your symptoms.
  10. You return to the doctor's office the next day. The doctor removes the catheter, downloads the data from the computer and uses it to see changes in acid levels throughout the 24-hour period.
  11. If the data from the test shows that you have GERD or another problem, your doctor will discuss treatment options with you.
How can I help you?