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Gastric Acid Concentration (24-Hour Urinary Excretion)

Published: August 9, 2026Updated: August 17, 2026

This test measures how much acid your stomach produces over 24 hours by analyzing urine for markers related to gastric acidity.

Quick summary

["Helps diagnose conditions like Zollinger-Ellison syndrome or excessive stomach acid."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
11892-7
Short code
GA from AC.Hadlock84
Synonyms
GA from AC.Hadlock84
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-ac-hadlock
CPT
82553
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

Your urine is collected over 24 hours to detect metabolites linked to gastric acid secretion. The test indirectly assesses acid production by the stomach lining.

Why It Matters for Your Health

High or low acid levels can cause symptoms like heartburn, ulcers, or digestive issues. This test helps identify if your stomach is producing too much or too little acid.

Common Conditions Monitored

Used to diagnose conditions like Zollinger-Ellison syndrome (a rare tumor causing excess stomach acid) or evaluate symptoms of acid-related disorders.

Sample Collection Process

You’ll collect all urine for 24 hours in a special container. The test measures urinary markers that reflect your stomach’s acid output.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urinary pH/Ammonia Test (Gastric Acid)

Frequently asked questions

What does an abnormal result mean?
Abnormal results may indicate conditions like excessive stomach acid production (hyperchlorhydria), which can lead to ulcers or other gastrointestinal issues. Your doctor will discuss findings with you.
How often is this test recommended?
This test is typically ordered if you have symptoms like frequent heartburn, unexplained ulcers, or digestive discomfort. Your doctor may recommend it as part of a diagnostic evaluation.
What should I do if I miss urine collection?
If you miss any urine during the 24-hour period, start collecting again immediately. Discard any urine collected before the start time and continue from the new start.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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