Understanding Your Diagnostic Test: Purpose, Preparation, and What to Expect
A 24-hour stool chloride test measures the amount of chloride in your stool to help diagnose certain digestive conditions.
{"Measures chloride levels in a 24-hour stool collection","Mainly used to screen for cystic fibrosis in infants and children","Abnormally high levels may indicate pancreatic or intestinal problems","Involves collecting all stool over a 24-hour period","Results help doctors evaluate digestive enzyme function"}
Key facts at a glance
- LOINC
- 55837-9
- Short code
- STCL24
- Synonyms
- Chloride 24h Stl-sCnc
- Category
- electrolyte
- Sample
- stool
- Container
- Clean, dry, wide-mouthed plastic container with tight-fitting lid; special 24-hour stool collection container may be used
- Units
- not specified
- Ref low
- 0
- Ref high
- 20
- Critical range
- — – 90 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Ion-selective electrode (ISE) or titrimetric method
- CPT
- 82436
- SNOMED
- 270271006
- Specimen volume
- Entire 24-hour stool collection; minimum 5-10g if aliquot required
- Stability
- Refrigerate at 2-8°C if delay in transport >2 hours; stable up to 72 hours refrigerated. Do not freeze.
- TAT
- 24–72 hours
- Order
- routine
What is this test? This test is a diagnostic procedure used to collect information about your health, evaluate symptoms, and help your clinician make decisions about treatment or follow-up care.
The stool chloride test measures the concentration of chloride, an electrolyte, in your stool. You will collect all stool produced over a 24-hour period in a special container provided by your healthcare provider. The laboratory then analyzes the sample to determine the chloride content.
Why do I need this test? Your clinician may recommend this test to investigate symptoms, monitor a known condition, check how treatment is working, or identify changes that may require additional evaluation or care.
This test is most commonly used to screen for and monitor cystic fibrosis, a genetic condition that affects the lungs and digestive system. In cystic fibrosis, the pancreas does not produce enough digestive enzymes, leading to abnormal chloride levels in stool. The test may also be used to evaluate pancreatic insufficiency or other digestive disorders.
How do I prepare for the test? Follow all instructions from your clinician or testing center, including guidance about food, drinks, medicines, activity, clothing, and arrival time, and ask questions if anything is unclear.
Your healthcare provider will give you specific instructions. Generally, you should continue your normal diet and activities. You will receive a special collection container and may need to avoid certain medications or supplements. It is important to collect ALL stool during the 24-hour period for accurate results.
What happens after the test? After the test, your care team will provide any immediate instructions, explain when results may be available, and discuss next steps if additional evaluation or treatment is needed.
Once you have completed the 24-hour collection, return the container to your healthcare provider or laboratory as instructed. Results are typically available within a few days. Your healthcare provider will discuss what the results mean for your health.
Reference range
0-20 mmol/Lnot specified
Complete 24-hour stool collection; refrigerate specimen during collection period. Avoid laxatives and enemas.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated stool chloride levels are most commonly associated with cystic fibrosis. In this condition, the high chloride concentration occurs because the pancreas cannot properly secrete digestive enzymes, leading to malabsorption. In infants with cystic fibrosis, stool chloride levels are typically significantly higher than normal. This test is particularly useful as a screening tool because it is non-invasive and can provide early detection.
Abnormal results may also indicate pancreatic insufficiency, where the pancreas fails to produce enough digestive enzymes. This can occur in conditions such as chronic pancreatitis or pancreatic cancer. In some cases, certain intestinal disorders may also affect stool chloride levels. Your healthcare provider will interpret your results in the context of your symptoms and other test findings.
Frequently asked questions
Is the 24-hour stool collection painful?
Can I take my regular medications during the collection period?
What if I miss a bowel movement during the 24-hour period?
How long will I need to do this test?
Sources
- 1
- 2
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 10, 2026. · Read our editorial policy