Esophagus tests measure muscle pressure and
movement, coordination, and strength of the tube that connects the throat to
the stomach (esophagus). They test how well the ring of muscles
(sphincters) at the top and bottom of the esophagus work. Esophagus tests also measure the movement and volume of gas, liquid, and solid through the esophagus and its pH (acid or non-acid). See a picture of the
The most common esophagus
(esophageal acidity test), which measures the acid content (pH) in the esophagus. A low pH for long periods
may mean 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
Weak muscle contractions during
swallowing that slow the rate at which food or stomach acid is cleared from the
Abnormally strong contractions (spasms) that can cause
chest pain or the sensation that food is stuck after swallowing (dysphagia).
Either pH or manometry testing can be combined with a test that measures the movement and volume of gas, liquid, and solid through the esophagus (multichannel intraluminal impedance testing, or MII). When MII is combined with manometry (MII-EM), it can show how the muscles of the esophagus are contracting when there is food or liquid in the esophagus. When MII is combined with pH testing (MII-pH), it can detect reflux from the stomach into the esophagus and measure both the volume and the acidity.
Why It Is Done
Tests on the esophagus are done
Help find the cause of chest pain that is not caused by heart problems (called noncardiac chest pain).
Help determine the cause of GERD symptoms for a person who has
not been helped by medicine and whose esophagus looks normal during an
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.
To evaluate how the esophagus works before surgery for GERD.
Esophagus tests are usually not done in people with GERD if their symptoms are well controlled with medicine.
How To Prepare
To prepare for an esophagus test:
Do not take antacids (such as Tums or Rolaids)
for 24 hours before
Follow your doctors instructions for using other acid reducers or blockers, such as famotidine (Pepcid) or omeprazole (Prilosec), before the test.
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
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 be seated. 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
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.
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 wireless pH monitoring, a capsule
containing a pH-sensitive transmitter is placed in your esophagus during an
endoscopy procedure. You carry a small pager-sized receiver in your pocket or
wear it around your waist. During the monitoring period, you will need to
use a diary to keep track of your activities and any symptoms you develop. 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.
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
You may be asked to swallow several times or to
drink liquids while pressure measurements are taken.
You may be asked to swallow, not swallow, and hold your breath during the test.
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.
If you have multichannel intraluminal impedance (MII) testing done with either pH or manometry, it will be done in very much the same ways as described above. The catheters used to do MII with pH or manometry testing will include instruments that measure volume of food and liquid in the esophagus as well as pH or pressure.
How It Feels
The local anesthetic sprayed into your nose and throat usually tastes slightly bitter and will make your tongue and throat feel numb and swollen.
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
If you have the wireless pH monitoring, you may be able to feel the capsule in your esophagus. You will not feel the capsule when it detaches and passes through your intestines and out of your body in your stool.
After the test is over, your nose and 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 get a nosebleed.
You may have irregular heartbeats (arrhythmias).
tube may go down the windpipe (trachea) instead of the esophagus as it is being
You may vomit material from your stomach and then breathe
it into your lungs (aspiration).
The tube may make a hole in the
Esophagus tests measure muscle pressure
and movement, coordination, and strength of the tube that connects the throat
to the stomach (esophagus). They test how well the ring of muscles
(sphincters) at the top and bottom of the esophagus work. Esophagus tests also measure the movement and volume of gas, liquid, and solid through the esophagus and its pH (acid or nonacid). Results are usually
available within a few days.
The pH of the esophagus is not acidic.
If acid is placed in the stomach, the pH of the esophagus does not go down.
The pH of the lower esophagus is
If acid is placed in the stomach, the pH of the lower esophagus goes down.
The pressure of the muscle contractions
that move food down the esophagus is normal.
contractions follow a normal pattern down the esophagus.
Contractions along the esophagus are
weak or uncoordinated.
The LES pressure is low.
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:
Taking certain medicines. Many medicines can affect the results of pH testing or esophageal manometry. Make sure you follow your doctor's instructions about which medicines to stop or to take before and during testing.
Smoking or drinking alcohol
within 24 hours of the test.
Eating or drinking within 8 hours of
the test, unless you are having prolonged pH monitoring at home. If you are having prolonged pH monitoring, try to eat normally and do your normal activities.
Detachment of the wireless pH capsule before the end of the recording time (usually 24 or 48 hours).
Movement of the catheter when you swallow.
What To Think About
Occasionally, samples of stomach secretions may
be taken during the pH monitoring test.
Combining multichannel intraluminal impedance testing with pH (MII-pH) can record reflux, even if it's not acidic. pH testing by itself will only record acidic reflux events.
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Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.
Hirano I, et al. (2007). ACG practice guidelines: Esophageal reflux testing. American Journal of Gastroenterology, 102(3): 668–685.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Primary Medical Reviewer
Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer
Jerome B. Simon, MD, FRCPC, FACP - Gastroenterology
How this information was developed to help you make better health decisions.