pH, Feces [1304]

Message

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

Test Code

PHFECL

Alias/See Also

1304

CPT Codes
83986

Preferred Specimen

5 grams liquid stool collected in a plastic screw-cap container

Minimum Volume

1 gram

Other Acceptable Specimens

Random stool collected in a plastic screw-cap container

Instructions

Random liquid or soft stool specimen collected in sterile plastic container or stool specimen container with spork (warehouse #77000).
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.

Transport Temperature

Frozen

Specimen Stability

Room temperature: 4 hours
Refrigerated: 24 hours
Frozen: 60 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Received thawed • Fecal specimens received in paint can

Methodology
Potentiometry

Setup Schedule

Set up: Sun-Fri; Report available: 2-4 days

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

Clinical Significance

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.

Performing Laboratory

Quest Diagnostics Nichols Institute

14225 Newbrook Drive

Chantilly, VA 20153

Last Updated: December 6, 2021

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.