Esophagus Tests

Test Overview

Esophagus tests measure muscle pressure and movement, coordination, and strength of the tube that connects the throat to the stomach (esophagus). It tests how well the ring of muscles (sphincters) at the top and bottom of the esophagus work. See a picture of the esophagus.

The most common esophagus tests include:

  • pH monitoring (esophageal acidity test), which measures the acid content (pH) in the esophagus. A low pH for long periods indicates frequent abnormal backflow (reflux) of stomach acid into the esophagus (gastroesophageal reflux disease, or GERD).
  • Esophageal manometry, which measures the strength and pattern of muscle contractions in the esophagus. This test can detect:
    • Weakness in the lower esophageal sphincter (LES), which allows acid to reflux into the esophagus.
    • Weak muscle contractions during swallowing that slow the rate at which food or stomach acid is cleared from the esophagus.
    • Abnormally strong contractions (spasms) that can cause chest pain or the sensation that food is stuck after swallowing (dysphagia).

Why It Is Done

Tests on the esophagus are done to:

  • Help determine whether chest pains may be caused by GERD.
  • Help determine the cause of GERD symptoms for a person who has not been helped by medicine and whose esophagus looks normal during an endoscopy test.
  • Monitor the effectiveness of treatment for GERD.
  • Detect spasms of the esophagus, which can cause chest pain, and problems with the ability of the esophagus to move food down to the stomach (motility problems).
  • Determine whether the esophagus is working normally.

How To Prepare

To prepare for an esophagus test:

  • Do not take antacids (such as Tums or Rolaids) or acid reducers (such as Axid, Pepcid, Tagamet, or Zantac) for 24 hours before the test unless the test is being done to evaluate the effectiveness of these medicines.
  • Stop taking other medicines—such as the proton pump inhibitors lansoprazole (Prevacid), omeprazole (Prilosec), pantoprazole (Protonix), esomeprazole (Nexium), or rabeprazole (Aciphex)—before testing. Your doctor will give you specific instructions.
  • Do not drink alcohol or smoke for 24 hours before the test.
  • Do not eat or drink for 8 to 12 hours before testing.
  • Tell your doctor if you have any other problems, such as enlarged esophageal blood vessels (esophageal varices), heart failure, or other heart conditions.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?) .

How It Is Done

You will lie on a table with your head on a pillow. You may be given a spray medicine that numbs your nose and throat. For each esophagus test, a thin, flexible tube will be passed through your nose or mouth to your lower esophagus and stomach. This may make you feel like you have to gag. To help overcome this feeling, concentrate on breathing slowly. Your pulse and blood pressure may be monitored while the tube is being inserted.

pH monitoring

  • A probe that measures pH will be passed through your nose or mouth into your lower esophagus. The probe monitors the pH in your esophagus so your doctor can tell whether the pH drops because of liquid from your stomach backing up into your esophagus.
  • For prolonged pH monitoring, the pH probe is attached to a small recorder. You carry the recorder by a strap around your waist or over your shoulder. The probe measures the pH of your esophagus for up to 24 hours while you go about your routine daily activities. During the monitoring period, you will need to use a diary to keep track of your activities and any symptoms you develop. You may be asked to avoid high-acid foods such as fruit, fruit juice, and tomatoes during the testing period. You will not be able to take a bath, except for a careful sponge bath, or do anything else that might get the monitor wet during the recording period.
  • For Bravo wireless pH monitoring, a capsule containing a pH-sensitive transmitter is placed in your stomach during an endoscopy procedure. You carry a small pager-sized receiver in your pocket or wear it around your waist. You will be instructed to press the symptom button when you have heartburn, chest pain, or regurgitation. You can bathe during the monitoring period. When the testing period is over, return the receiver and your diary to your doctor for evaluation. The transmitter capsule will pass out of your body in a bowel movement, usually within a few days. This type of testing may not be recommended if you have a history of a bowel obstruction.

Esophageal manometry

  • You will swallow a small tube attached to instruments (transducers) that measure pressure. The tube has holes in it that sense pressure along the esophagus. It will be positioned in different areas of your esophagus.
  • You may be asked to swallow several times or to drink water while pressure measurements are taken.
  • The results of the manometry test are displayed as a graph with a wave pattern that can be interpreted to determine if the esophagus is functioning normally.

How It Feels

When the tube goes through your nose or mouth into your esophagus, you may feel like coughing or gagging. The test may be easier if you try to take slow, deep breaths. You may not like the taste of the lubricant on the tube.

If you have a test that involves adding acid to your stomach, you may have heartburn pain and other symptoms of acid reflux.

After the test is over, your throat may feel sore. But this should improve within a day or so.


The chances that you will have problems from an esophagus test are rare.

  • You may have irregular heartbeats (arrhythmias).
  • The tube may go down the windpipe (trachea) instead of the esophagus as it is being inserted.
  • You may vomit material from your stomach and then breathe it into your lungs (aspiration).
  • The tube may make a hole in the esophagus (perforation).


Esophagus tests measure muscle pressure and movement, coordination, and strength of the tube that connects the throat to the stomach (esophagus). It also tests how well the ring of muscles (sphincters) at the top and bottom of the esophagus work. Results are usually available in 2 to 3 hours.

pH monitoring
  • The pH of the esophagus is between 4 and 6.
  • The pH of the lower esophagus is frequently below 4.
  • If acid is placed in the stomach, it lowers the pH of the lower esophagus.


Esophageal manometry
  • The pressure of the muscle contractions that move food down the esophagus is normal.
  • The muscle contractions follow a normal pattern down the esophagus.
  • Normal pressure of the lower esophageal sphincter (LES) is about 15 millimeters of mercury (mm Hg). The pressure is less than 10 mm Hg when the LES relaxes to let food pass into the stomach.
  • Muscle spasms are present in the esophagus.
  • Contractions along the esophagus are weak.
  • The LES pressure is less than 10 mm Hg.
  • The LES pressure is high and fails to relax after swallowing.


Many conditions can change the results of esophagus tests. Your doctor will discuss any significant abnormal results with you in relation to your symptoms and past health.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Medicines used to treat gastroesophageal reflux disease (GERD), such as antacids (Tums or Rolaids), acid reducers (Axid, Pepcid, Tagamet, or Zantac), or proton pump inhibitors (Prevacid, Prilosec, Nexium).
  • Medicines used to treat asthma and emphysema, especially theophylline.
  • Medicines used to treat Parkinson's disease, muscle spasms in the bladder and intestines, and some eye problems.
  • Corticosteroids , such as prednisone.
  • Heart and blood pressure medicines, such as calcium channel blockers, alpha-blockers, and beta-blockers.
  • Medicines that act on the nervous system, such as antianxiety medicines, anesthetics, and narcotics.
  • Smoking or drinking alcohol within 24 hours of the test.
  • Eating or drinking within 8 hours of the test.

What To Think About

  • Occasionally, samples of stomach secretions may be taken during the pH monitoring test.
  • Other tests may be done to help diagnose problems with the esophagus, including upper gastrointestinal (UGI) endoscopy, barium swallow, or upper gastrointestinal studies (upper GI series). For more information, see the medical tests Upper Gastrointestinal (UGI) Series and Upper Gastrointestinal Endoscopy.


Other Works Consulted

  • Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
  • Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.
  • Pagana KD, Pagana TJ (2006). Mosby’s Manual of Diagnostic and Laboratory Tests, 3rd ed. St. Louis: Mosby.


Author Monica Rhodes
Editor Maria Essig
Associate Editor Tracy Landauer
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
Last Updated April 30, 2009

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