Esophageal acid measurement is the measurement of the frequency and duration of stomach acid refluxing into the esophagus. It is the standard diagnostic test for acid reflux disease, as well as an assessment of the effectiveness of medication in controlling acid reflux in patients. So, who should undergo this test… or what symptoms are warning signs for patients? Here is the answer!
When is esophageal acid measurement performed?
- When confirmation of diagnosis is needed in patients with unclear or non-typical symptoms of acid reflux disease, such as chest pain not caused by heart disease, chronic cough, chronic hoarseness, etc.
- When evaluating treatment effectiveness, especially in patients whose symptoms have not improved after medication.
- When confirming diagnosis before surgery to treat acid reflux disease.
How to prepare before undergoing esophageal acid measurement?
- Do not eat or drink after midnight before the test.
- Stop antacid and acid reflux medications 1 week before the test (unless the doctor instructs to continue taking them to evaluate whether the medication adequately controls acid reflux; in that case, take the medication as usual, including on the morning of the test).
- If you have any questions about medication intake, consult your doctor.
- Perform your daily activities as usual before the test.
Procedure for esophageal acid measurement
There are two types of esophageal acid measurement depending on the patient’s suitability and medical indications. Both types measure acid reflux from the stomach into the esophagus as follows…
- Esophageal acid measurement by nasal catheter insertion
In this method, the patient undergoes esophageal motility testing to find the correct position of the lower esophageal sphincter before inserting the acid measurement catheter and to diagnose esophageal motility disorders often associated with acid reflux disease. Then, the acid measurement catheter is inserted. A local anesthetic is applied to the nose. A small plastic tube about 1 millimeter in diameter is inserted through the nostril, passed behind the oral cavity, and down into the esophagus during swallowing. The tip of the catheter has an acid level sensor, positioned in the lower esophagus. The catheter insertion takes about 10 minutes.
The catheter is connected to a small recording device that the patient carries for 24 hours. After insertion, the patient can go home and perform normal activities such as eating, working, and sleeping. During this time, if symptoms occur, the patient should record the details and press a button on the device to log the event for correlation with acid reflux. The patient returns the next morning to have the device removed and waits for the test results.
This method carries very low risk and may cause slight throat discomfort. Most patients do not experience problems with swallowing, sleeping, or daily activities.
- Esophageal acid measurement by capsule method
This method measures esophageal acid using a capsule about the size of a pencil eraser. Before capsule placement, the patient undergoes upper gastrointestinal endoscopy. The capsule is inserted into the esophagus through the nose or mouth and attached to the esophageal wall with a clip. The insertion tube is then removed. The capsule measures acid levels in the esophagus and transmits data to a recorder worn on the patient’s belt or waist.
With this method, the patient does not have a nasal tube, making it more convenient. The patient can perform normal activities, including meal times and sleeping. During symptomatic periods, the patient should record symptoms and press a button to log events. Data recording lasts 48 hours, after which the patient returns to have the device removed. The capsule attached to the esophageal wall usually detaches on its own within 5-7 days and is passed out with stool. The downside of this method is possible mild throat irritation when swallowing saliva and the need to avoid MRI scans for 30 days after the test.
Certain patients cannot undergo this method, such as those with implanted pacemakers, implantable defibrillators, a history of easy bleeding, severe esophageal stricture or inflammation, esophageal varices, or those who have had esophageal surgery.
Note Esophageal motility testing (Esophageal manometry) to locate the position for catheter insertion can be performed on the same day.
