Osmolality, Fecal
Also known as: Fecal Osmolality
Use
Distinction of osmotic from nonosmotic secretory diarrhea. A large deficit (>50 mOsm/kg) in the calculated osmolality (twice the sum of the stool sodium and stool potassium) from the measured stool osmolality indicates osmotic diarrhea.
Special Instructions
Ensure that the stool sample is collected without the addition of water to avoid compromising the test results. Use only a small plastic container and do not use a large paint can.
Limitations
The reference range for this test has not been established, which may affect the interpretation of results. Additionally, this test may require additional time for confirmatory or reflex tests based on initial findings. Improper sample handling, such as contamination with urine or non-frozen storage, can lead to sample rejection.
Methodology
Other
Biomarkers
LOINC Codes
- 2693-0
- 2693-0
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Stool
Volume
15 mL
Minimum Volume
Not provided
Container
Small plastic container
Collection Instructions
Stool sample must be collected without addition of water.
Storage Instructions
Freeze
Causes for Rejection
Stool not liquid; stool contaminated with urine; paint can submitted; non-frozen stool
Other tests from different labs that may be relevant