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Synonyms
- Fecal pH
- Stool pH
Expected Turnaround Time
2 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Documents
Specimen Requirements
Specimen
Stool (fresh random)
Volume
1 g
Minimum Volume
0.5 g
Container
Clean container
Storage Instructions
Room temperature
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Patient Preparation
Barium procedures and laxatives should be avoided for one week prior to collection of the specimen.
Causes for Rejection
Specimen contaminated with urine; specimen on outside of container
Test Details
Use
Detect carbohydrate and fat malabsorption; evaluate small intestinal disaccharidase deficiencies
Limitations
This test was developed, and its performance characteristics determined, by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Aqueous stool suspension measured with pH paper
Reference Interval
pH: 0 to 6 months: 4.5–5.5
>6 months: 7.0–7.5
Additional Information
Stool pH is dependent in part on fermentation of sugars. Colonic fermentation of normal amounts of carbohydrate sugars and production of fatty acids accounts for the normally slightly acidic pH. If disaccharide intolerance is suspect, simple tests may be performed. Slightly alkaline pH may occur in cases of secretory diarrhea without food intake, colitis, villous adenoma, and possibly with antibiotic usage (with resultant impaired colonic fermentation). A stool pH of <6 (measured by pH paper) is suggestive evidence of sugar malabsorption. Children and some adults notice that their stools have a sickly sweet smell as the result of volatile fatty acids and the presence of undigested lactose. Low stool pH also contributes to the excoriation of perianal skin which frequently accompanies the diarrhea.1
High fecal pH may be a risk factor for colorectal cancer.2-6 Intake of oat bran (75−100 g/day over a 14-day period) has been shown capable of reducing fecal pH by 0.4 units.2 There is evidence, however, that high fecal pH may be secondarily rather than primarily related to cancer risk.3
Footnotes
1. Cooper BT. Lactose deficiency and lactose malabsorption. Dig Dis. 1986; 4(2):72-82 (review). 3102130
2. Kashtan H, Stern HS, Jenkins DJA, et al. Manipulation of fecal pH by dietary means. Prev Med. 1990 Nov; 19(6):607-613. 2263571
3. Kashtan H, Gregoire RC, Bruce WR, Hay K, Stern HS. Effects of sodium sulfate on fecal pH and proliferation of colonic mucosa in patients at high risk for colon cancer. J Natl Cancer Inst. 1990 Jun 6; 82(11):950-952. 2342129
4. Thornton JR. High colonic pH promotes colorectal cancer. Lancet. 1981 May 16; 1(8229):1081-1083. 6112450
5. Malhotra SL. Faecal urobilinogen levels and pH of stools in population groups with different incidence of cancer of the colon, and their possible role in its aetiology. J R Soc Med. 1982 Sep; 75(9):709-714. 7120255
6. Walker AR, Walker BF, Walker AJ. Faecal pH, dietary fibre intake, and proneness to colon cancer in four South African populations. Br J Cancer. 1986 Apr; 53(4):489-495. 3011051
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 010991 | pH, Stool | 2755-7 | 010991 | pH, Stool | 2755-7 |