pH, Feces
Test Summary
This test may help evaluate carbohydrate malabsorption as the cause of osmotic diarrhea [1].
Osmotic diarrhea is caused by the osmotic effect of a substance that retains water in the intestine lumen. Conditions associated with osmotic diarrhea include ingesting poorly absorbed solutes (eg, sorbitol, mannitol, laxatives containing magnesium) and enzyme dysfunction (eg, lactose intolerance) [1]. In patients with osmotic diarrhea, a stool pH <5.5 may suggest carbohydrate malabsorption when chloridorrhea is excluded, while PH>5.5 is most likely due to other osmotic causes but does not rule out carbohydrate malabsorption [2].
Disruption of the acid-base balance has been observed in patients with various conditions, such as severe systemic inflammatory response syndrome, multiple organ failure, sepsis, and colorectal cancer. Abnormal stool pH has been correlated with higher mortality in patients treated in the intensive care unit [3].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Block DR, et al. Body fluids. In: Rifai R, et al, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier Inc; 2022.
2. Caspary WF. Clin Gastroenterol. 1986;15(3):631-655.
3. Osuka A, et al. Crit Care. 2012;16(4):R119.
Aliases
- N/A
Specimen Collection
Special Instructions
Preferred Specimen
Minimum Volume
Instructions
Adult and older children patients can collect the specimen by passing feces into plastic wrap stretched loosely over the toilet bowl. Then transfer 5 g of the stool specimen into the plastic container. With young children and infants wearing diapers, the diaper should be lined with clean plastic wrap to prevent absorption. A pediatric urine bag can be attached to the child to ensure that the stool specimen is not contaminated with urine. Then transfer 5 g of the stool specimen from the plastic lined diaper to the plastic container. Do not submit the diaper itself. Freeze and transport frozen.
Patient Preparation
Storage
Transport Temperature
Specimen Stability
- Room temperature: 4 hours
- Refrigerated: 24 hours
- Frozen: 60 days
Limitations
Other Acceptable Specimens
Unacceptable Specimens
Order Code
EPIC (Premier) Code
Includes
CPT Code
- 83986
Billing Code
- 650036
CPT Statement
Methodology
FDA Status
Physician Attestation of Informed Consent
Testing Laboratory
14225 Newbrook Drive
Chantilly VA, 20153
Department
Reference Range
| Newborns (Neonates) Birth through 28 days | 5.0-7.0 pH units |
| Infants >1 month through 2 years | |
| Bottle Fed; Neutral or slightly alkaline | ≥7.0 pH units |
| Breast fed; slightly acidic | <7.0 pH units |
| >2 Years | 7.0-7.5 pH units |
Setup Schedule / Expected Turnaround Time
Specimen Collection
Special Instructions
Preferred Specimen
Minimum Volume
Instructions
Adult and older children patients can collect the specimen by passing feces into plastic wrap stretched loosely over the toilet bowl. Then transfer 5 g of the stool specimen into the plastic container. With young children and infants wearing diapers, the diaper should be lined with clean plastic wrap to prevent absorption. A pediatric urine bag can be attached to the child to ensure that the stool specimen is not contaminated with urine. Then transfer 5 g of the stool specimen from the plastic lined diaper to the plastic container. Do not submit the diaper itself. Freeze and transport frozen.
Patient Preparation
Storage
Transport Temperature
Specimen Stability
- Room temperature: 4 hours
- Refrigerated: 24 hours
- Frozen: 60 days
Limitations
Other Acceptable Specimens
Unacceptable Specimens
Result Information
Methodology
Testing Laboratory
Reference Range
| Newborns (Neonates) Birth through 28 days | 5.0-7.0 pH units |
| Infants >1 month through 2 years | |
| Bottle Fed; Neutral or slightly alkaline | ≥7.0 pH units |
| Breast fed; slightly acidic | <7.0 pH units |
| >2 Years | 7.0-7.5 pH units |