Intramucosal pH, stomach
This test measures the acidity (pH) at the surface of the stomach lining, usually during an upper endoscopy. It can help assess acid exposure and the condition of the stomach mucosa.
["The result provides information about stomach acidity and may help evaluate reflux-related irritation, inflammation, ulcers, or other mucosal abnormalities."]
Key facts at a glance
- LOINC
- 76280-7
- Short code
- Intramucosal pH Stom
- Synonyms
- Intramucosal pH Stom
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 44
- Ref high
- 147
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84075
- SNOMED
- 27550007
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What the test measures
Stomach acid has a low pH. Measuring pH directly at the stomach lining shows how acidic the environment is where acid contacts the mucosa.
How the test is performed
During an upper endoscopy, a small probe is placed through the mouth and positioned in the stomach. The probe measures pH at selected locations in the stomach lining.
Why it may be ordered
Clinicians may order this measurement when evaluating persistent indigestion, upper abdominal discomfort, suspected reflux-related injury, gastritis, or ulcers, particularly when standard stomach-acid testing does not provide enough information.
Factors that can affect the result
Recent meals, medications such as acid-reducing drugs, prior endoscopy procedures, and the exact area sampled can influence the measurement. Preparation instructions should therefore be followed carefully.
Reference range
Adult: 44-147 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An abnormal intramucosal pH may indicate excessive or prolonged acid exposure or impaired protective mechanisms in the stomach. Results should be interpreted with symptoms, medication history, endoscopic findings, and other tests because a single measurement cannot establish a diagnosis by itself.
Short name
Stomach intramucosal pH
Frequently asked questions
Does this test require fasting?
Is stomach intramucosal pH the same as a stomach-acid aspiration test?
Does a low pH always mean that medication is needed?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy