Esophageal pH (acid) Test

The esophageal pH (acid) test is an outpatient (ambulatory) procedure used to measure the pH (amount of acid) flowing into the esophagus from the stomach during a 24-hour period. The test is most often used to identify the cause of symptoms, including:

  • Heartburn in patients whose medical treatment failed
  • Chest Pain
  • Chronic Cough
  • Asthma
  • Throat Symptoms (including hoarseness)

These symptoms can be the result of chronic acid reflux, also known as gastroesophageal reflux disease (GERD). The test may also be used in patients to determine the effectiveness of current heartburn or reflux treatments.

What Happens During an Esophageal pH (acid) Test?
For the Esophageal pH (acid) Test, a small probe is inserted through the patient’s nostril and placed near the lower esophagus. The probe sends a signal remotely or directly with a tube placed down the nose to a monitor worn by the patient. If the remote option is used, a disposable capsule is used and placed utilizing an endoscope.

The patient will be given instructions by a nurse on how to use the monitor to record:

  • When symptoms occur
  • When you start eating
  • When you finish eating
  • When you start lying down
  • When you finish lying down

The patient should try and follow as close to a normal routine as possible, only lying down at times when would be typical for a normal day and eating regular meals. Do not change your habits while you are being monitored as these changes will make it difficult for your physician to get a clear picture of what is happening to cause your symptoms.

Preparing for Esophageal pH (acid) Test
Patients undergoing an esophageal pH (acid) test should not eat or drink six hours before the test (your doctor’s instruction may vary).

Because medications like PPIs, also known as proton pump inhibitors (Prilosec, Aciphex, Nexium, etc.), H2 blockers (Axid, Pepcid, Tagamet, Zantac, etc.), antacids (Alka-Seltzer, Tums, Maalox, etc.), Calcium channel blockers (Calan, Adalat, Isoptin, etc.) and Nitrates (Isordil, Isosorbide, Nitrobid) may affect the results of an esophageal pH (acid) test, patients should talk to their doctor about all medications they are taking and whether or not these need to be discontinued before the test. Do not discontinue use of medications without speaking with your doctor first. Medications, like the ones mentioned, could take a week before they are sufficiently out of your system.