G
CDSA2.0
A S T R O I N T E S T I N A L
A
S S E S S M E N T S
pH
What are the key factors that
determine stool pH?
What clinical conditions are
associated with high stool pH?
The major factors that determine stool pH are amount and types of fiber entering the
large bowel, bacterial fermentation of the fiber, short-chain fatty acid levels, and stool
transit time.
Excessive protein consumption, slow transit time/constipation, and inadequate
dietary fiber may all contribute to an alkaline (> 7.2) stool pH.1
Acidity of the stool is often related to diarrhea or carbohydrate malabsorption.
Additionally, use of osmotic laxative agents, herbal or chemical, could cause an
acidic pH.
How does one modify
an abnormal stool pH?
If stool pH is high (alkaline), a key strategy is to correct constipation, address dietary
protein excess, improve transit time, and ensure adequate quantities of soluble and
insoluble fiber intake. Oat bran and cellulose/hemi-cellulose from vegetables are
good sources. If pH is too low (acidic), address the cause of diarrheal syndromes:
viral infection, possible malabsorption, or osmotic diarrhea2 from food,3 medications,
or bacterial toxins.
What is pH?
Fecal pH indicates the relative acidity
or alkalinity of the colonic environment.
Factors that have an impact on stool
pH include fiber and food constituent
intake, fermentive processes,
bacterial populations, antibiotics,
and stool transit time.
Turn-around Time 14 days
© 2004 Genova Diagnostics
S
U P P O R T
G
U I D E
1
CDSA 2.0 Support Guide_pH
How do I order this test?
For CDSA 2.0 test kits, Interpretive Guidelines or information, please
call a GSDL Accounts Receivable representative at 888-201-8333 or
use our secure web contact center at www.gsdl.com/billing.
References
1 Newmark HL, Lupton JR. Determinants and consequences of colonic
luminal pH: implications for colon cancer. Nutr Cancer 1990;14:161-73.
2 Payne ML, Craig Wj, Williams AC. Sorbitol is a possible risk factor for
diarrhea in young children. J Am Diet Assoc 1997 May;97(5):532-4.
3 Ament ME. Malabsorption of apple juice and pear nectar in infants
and children: clinical implications.
J Am Coll Nutr 1996 Oct;15(5 Suppl):26S-29S.
63 Zillicoa Street
Asheville, NC 28801
800.522.4762
www.gsdl.com
This information is for the sole use of a licensed health care practitioner and is for educational
purposes only. It is not meant for use as diagnostic information. All claims submitted to
Medicare/Medicaid for GSDL laboratory services must be for tests that are medically necessary.
“Medically necessary” is defined as a test or procedure that is reasonable and necessary for the
diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member.
Consequently, tests performed for screening purposes will not be reimbursed by the Medicare program.
© 2004 Genova Diagnostics
g,sg,cdsa2_pH,082404
2