Gastric pH and Carbon Dioxide Content (Serum/Plasma)
This test measures the pH level and carbon dioxide content in your stomach fluid, often used to assess acidity and digestive function.
["Helps diagnose acid-related digestive issues or evaluate stomach function."]
Key facts at a glance
- LOINC
- 60819-0
- Short code
- Gastric pCO2
- Synonyms
- Gastric pCO2
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- gastric-tonometry
- 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
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like heartburn, frequent stomach pain, nausea, or unexplained weight loss. It may also be used to check for conditions like gastroesophageal reflux disease (GERD), ulcers, or other stomach disorders that affect acid production or digestion.
What to Expect Before the Test
You may be asked to fast for a few hours before the test, depending on your doctor’s instructions. Avoid eating or drinking anything except water. If you’re taking certain medications (like acid reducers), your provider may ask you to stop them temporarily.
How the Test Is Performed
A small sample of your stomach fluid is collected using a thin tube inserted through your nose into your stomach. The fluid is then sent to a lab for analysis of pH and carbon dioxide levels. The procedure is usually quick and painless but may cause mild discomfort.
What the Results Mean
Results help determine if your stomach produces too much or too little acid, which can indicate conditions like hyperchlorhydria (excess stomach acid) or hypochlorhydria (low stomach acid). Your doctor will interpret the results in relation to your symptoms and medical history.
Reference range
Adult: 10-40 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.
◆Associated findings1
Short name
Gastric pCO₂ Profile
Frequently asked questions
How does this test help doctors diagnose conditions?
What are the typical reference ranges for 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