Gastric Acid Concentration (Qualitative, Manual pH Probe)
This test measures the acidity level in your stomach fluid using a manual pH probe. It helps assess whether your stomach produces enough acid or too little.
["Determines stomach acid levels to check for conditions like hyperchlorhydria or hypochlorhydria."]
Key facts at a glance
- LOINC
- 14372-7
- Short code
- RBC # Gast Manual
- Synonyms
- RBC # Gast Manual
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- manual-count
- CPT
- 84484
- SNOMED
- 302774002
- 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 This Test Measures
The test involves swallowing a small, flexible tube with a probe at its tip. The probe measures the acidity (pH) of your stomach fluid. Results are qualitative, meaning they indicate whether acid levels are normal, too high, or too low rather than providing a specific numeric value.
How the Test Is Performed
You’ll be asked to swallow the tube, which is guided to the stomach. The probe collects fluid for pH measurement. The test is quick but may cause mild discomfort or gagging. No special preparation is needed, but fasting may be advised by your doctor.
Preparation and Risks
No fasting is typically required, but your doctor may instruct you to avoid certain foods or medications beforehand. Rarely, the tube may cause mild nausea or discomfort. If you have a swallowing disorder or severe gag reflex, your doctor may choose an alternative test.
Why It Matters
Abnormal acid levels can signal conditions like gastroesophageal reflux disease (GERD), ulcers, or digestive disorders. High acid levels may indicate hyperchlorhydria, while low levels may suggest hypochlorhydria or other stomach issues.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is often used to diagnose or monitor conditions affecting stomach acid production. It helps guide treatment for symptoms like heartburn, indigestion, or unexplained nausea. Results may inform decisions about medication adjustments or further testing.
Short name
Gastric pH (Qualitative)
Frequently asked questions
What causes stomach acid levels to be abnormal?
How long does it take to get results from this test?
Can I eat or drink anything before this test?
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 17, 2026. · Read our editorial policy