Esophageal pH Test Test
An esophageal pH test measures how often and how long stomach acid enters your esophagus. It helps diagnose acid reflux or GERD and can check if treatment is working.
What this test measures
An esophageal pH test measures how often stomach acid enters your esophagus and how long it stays there. It uses a thin tube or a pH probe placed in the esophagus to measure acid levels over 24 to 96 hours.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
High acid levels may be a sign of acid reflux, GERD, esophagitis (swelling or inflammation of the esophagus), stricture (narrowing of the esophagus), or Barrett's esophagus (damage to the esophageal lining that raises cancer risk).
Frequently asked questions
What is an esophageal pH test?
It measures how often and how long stomach acid enters your esophagus using a thin tube or pH probe placed in the esophagus.
Why is this test done?
It is most often used to diagnose acid reflux or GERD, and to see if treatment for GERD is effective.
How long does the test take?
The test measures acid levels for 24 to 96 hours.
What does a high acid level mean?
It may indicate acid reflux, GERD, esophagitis, stricture, or Barrett's esophagus.
What happens if GERD is not treated?
Untreated GERD can damage the esophagus and lead to more serious health problems like esophagitis, strictures, or Barrett's esophagus.
Related lab tests
Sources
- MedlinePlus: Esophageal pH Test — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.