Esophageal pH Test
Reviewed
Also called: esophageal pH monitoring, 24-hour esophageal pH test, esophageal reflux monitoring, esophageal acidity test, pH monitoring, pH probe study
An esophageal pH test measures how often stomach acid enters your esophagus (the muscular tube that carries food and liquids from your mouth to your stomach).
Specimen: Not applicable (esophageal pH measurement via catheter or wireless probe)
Why this test may be ordered
- To diagnose acid reflux or GERD
- To see if treatment for GERD is effective
Preparation and collection
You should not eat or drink (fast) for four to six hours before the procedure. You may be asked to stop taking certain medicines, such as antacids, for 24 hours or for as long as two weeks before your test. Your provider will let you know which medicines to avoid and for how long. Tell your provider if you have a pacemaker or an implantable heart defibrillator. Tell your provider if you have had problems with your esophagus before or if you have a history of bleeding problems.
An esophageal pH test may be done using a thin tube called a catheter or with a wireless pH probe (a small, capsule-like device). The monitor will measure your acid levels for 24 hours. You will keep a diary of your symptoms and the food you eat during these 24 hours. The probe will measure acid levels for 48 to 96 hours.
During a catheter test, you may feel some mild discomfort in your nose and throat, but it usually doesn't last long. You may also feel like gagging when the tube is inserted. Rarely, the test can cause a nosebleed. During a wireless test, you may have a sore throat from the endoscope. In very rare cases, the test may cause a tear in the lining of the esophagus.
Understanding results
If your results show high acid levels, it may be a sign of one of the following conditions: Acid reflux, GERD.
- High acid levels: If your results show high acid levels, it may be a sign of one of the following conditions: Acid reflux, GERD, Esophagitis, a condition that cause swelling and/or inflammation of the esophagus. It can cause difficulty swallowing. Stricture, a narrowing of the esophagus that can make it hard to swallow and cause breathing problems, Barrett's esophagus, a condition in which the lining of the esophagus is damaged by stomach acid. It can raise the risk of developing cancer of the esophagus. Limitation: Esophagitis, strictures, and Barrett's esophagus can happen if GERD is left untreated or if treatment is not effective. Next step: If your symptoms don't improve or are more serious, your provider may recommend treatments to reduce or block acid production.
- Acid reflux or GERD diagnosed: Also, if not treated, GERD can damage the esophagus and lead to more serious health problems. Limitation: While acid reflux and GERD are not life-threatening, the symptoms can be very uncomfortable and affect your quality of life. Next step: If you've been diagnosed with acid reflux or GERD, you may be able to reduce or eliminate your symptoms with diet and lifestyle changes.
- Procedure may cause mild discomfort or rare complications such as nosebleed or esophageal tear.
- Results may be affected by recent use of acid-reducing medications or by eating patterns during the test.
What to do next
If you have questions about your results, talk to your provider.
- How should I prepare for the esophageal pH test?
- What are the risks of the catheter and wireless probe methods?
- What do my results mean for my treatment plan?
- Can I eat normally during the monitoring period?
- When will I get my results and discuss next steps?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.