Osmolality, Fecal
Also known as: FEC OSMO
Use
The Fecal Osmolality test is used to measure the concentration of osmotically active particles in liquid stool. It helps in assessing patients with chronic diarrhea for malabsorption disorders, bacterial overgrowth, or other gastrointestinal conditions that result in an osmotic diarrhea. It is also useful in detecting contamination of stool specimens by hypotonic fluids such as water or urine, which may occur in some sample collections.
Special Instructions
The test requires collection of liquid stool without the addition of saline or water to liquefy the sample. Specific ARUP-supplied transport vials are used for specimen submission. The collection and handling instructions must be followed precisely to avoid sample rejection.
Limitations
The test cannot be performed on formed stools, and samples containing media or preservatives will be rejected. The result is not suitable for determining the specific osmotic agents causing diarrhea but rather provides a general osmolality measurement. Incorrect sample handling, such as contamination with urine or water, can lead to inaccurate results due to dilution.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 2693-0
- 2693-0
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Stool
Volume
5 mL
Minimum Volume
0.5 mL
Container
Unpreserved stool transport vial (ARUP Supply #40910)
Collection Instructions
Do not add saline or water to liquefy sample. Transfer to an unpreserved stool transport vial.
Storage Instructions
Keep frozen until testing.
Causes for Rejection
Formed stool, specimens in media or preservatives.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 1 week |
| Frozen | 1 month |