Lab Test

pH, Stool

Stool pH, Fecal pH

Test Codes



Barium procedures and laxatives should be avoided for one week prior to collection of the specimen.

Specimen Collection Criteria

Collect: Random stool specimen in a sterile collection cup.

  • Stool must be liquid in consistency. Formed (solid) stool will NOT be accepted.
  • Refrigerate the specimen immediately after collection. 

Physician Office/Draw Specimen Preparation

Refrigerate (2-8°C or 36-46°F) the specimen immediately after collection. Freeze (-20°C/-4°F or below) specimens that will not be received in the Laboratory within one hour of collection.

Preparation for Courier Transport

Transport: Stool specimen, frozen (-20°C/-4°F or below).

Rejection Criteria

Formed (solid) stool specimens.

Specimens not collected and processed as indicated.

In-Lab Processing

The specimen should be frozen (-20°C/-4°F or below) if not analyzed within one hour of collection.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 1 hour
Frozen (-20°C/-4°F or below): Undetermined

Specimen Storage in Department Prior to Disposal:

Specimens are disposed within 48 hours of testing.


Royal Oak Automated Chemistry Laboratory


Sunday – Saturday, 24 hours a day.
Results available within 24 hours.

Reference Range

0-30 Days (Newborns): 5.0 - 7.0.
Older than 30 Days: 7.0 - 7.5.

Test Methodology

Manual pH test strip.


  • Decreased stool pH may be due to intestinal lactase deficiency, high lactose intake or decreased absorption of fat or carbohydrates.
  • Increased stool pH may be seen in secretory diarrhea without food intake, colitis, villous adenoma or increased protein breakdown.

Clinical Utility

Stool pH may be used as a screening test for carbohydrate and fat malabsorption. It may also aid in the evaluation of small intestinal disaccharidase deficiencies.

CPT Codes



Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.