Phstl
A stool pH test measures the acidity or alkalinity of your stool to evaluate digestive health and nutrient absorption.
{"Stool pH test evaluates intestinal health and nutrient absorption","Normal stool pH ranges from 6.5 to 7.5","Abnormal pH may indicate lactose intolerance, malabsorption, or bacterial imbalances","The test uses a small stool sample collected at home","Results help doctors diagnose digestive disorders"}
Key facts at a glance
- LOINC
- 2755-7
- Short code
- STOOLPH
- Synonyms
- pH Stl
- Category
- chemistry
- Sample
- serum
- Container
- Clean, dry wide-mouthed stool container
- Units
- not specified
- Ref low
- 7
- Ref high
- 8
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Potentiometry using pH electrode
- CPT
- 83903
- SNOMED
- 187389003
- Specimen volume
- Approximately 5-10 grams of stool
- Stability
- Analyze within 2 hours of collection; if delay, refrigerate at 2-8°C for up to 24 hours
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 1–4 hours
- Order
- routine
What is a Stool pH Test?
A stool pH test is a simple laboratory test that measures the acidity level in your stool. The pH scale ranges from 0 to 14, with 7 being neutral. Your stool's pH value can provide important information about how well your digestive system is working and whether your intestines are absorbing nutrients properly.
How is the Test Performed?
For this test, you will need to collect a small sample of fresh stool. Your healthcare provider will give you a special collection container. It is important to collect the sample before mixing with toilet water. The sample should be delivered to the laboratory as soon as possible, preferably within a few hours of collection. No special preparation or fasting is typically required, but you should follow your doctor's specific instructions.
What Do the Results Mean?
Normal stool pH typically ranges from 6.5 to 7.5. A pH value below 6.5 indicates acidic stool, which may suggest carbohydrate malabsorption, lactose intolerance, or bacterial overgrowth in the intestines. A pH value above 7.5 indicates alkaline stool, which may be associated with protein malabsorption, pancreatic insufficiency, or certain bacterial infections. Your doctor will interpret your results based on your symptoms and medical history.
Reference range
7.0-8.0not specified
No special preparation or fasting required; collect fresh random stool specimen, avoid urine contamination
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Does the stool pH test hurt?
Do I need to fast before the test?
How long does it take to get results?
What should I do if my results are abnormal?
Sources
- 1
- 2
- 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