Stool color
Normal value: Brown Clinical implication: 1. Yellow to yellow-green : severe diarrhea 2. Green : severe diarrhea Black: resulting from bleeding into the upper gastrointestinal tract (>100 ml blood) 3. Tan or Clay colored : blockage of the common bile duct. 4. Pale greasy acholic (no bile secretion) stool found in pancreatic insufficiency.
Chemical examination Water pH Occult blood Urobilinogen Porphyrins Nitrogen Normal values Up to 75 % 6.5-7.5 Negative 50-300 g/24hr Coporphyrins:400-1200g/24hr Uroporphyrins:10-40 mg/24hr <2.5 g/24hr
Clinical Implications
C. ”Pasty” stool is associated with a high fat content in the stool:
1. A significant increase of fat is usually detected on gross examination
2. With common bile duct obstruction, the fat gives the stool a putty- like appearance.
3. In cystic fibrosis, the increase of neutral fat gives a greasy, “butter stool” appearance.
Consistency Size and shape Gross blood,Mucous,Pus, Parasites
Normal values in stool analysis
Microscopic examination
Fat (Colorless, neutral fat (18%) and fatty acid crystals and soaps)
2. Bile pigments and salts 3. Intestinal secretions, including mucus
4. Leukocytes that migrate from the bloodstream 5. Epithelial cells that have been shade 6. Bacteria and Inorganic material(10-20%) chiefly calcium and phosphates. Undigested and unabsorbed food.
Stool pH
Normal value: Neutral to acid or alkaline Clinical implication 1. Increased pH ( alkaline) a. protein break down b. Villous adenoma c.Colitis d.Antibiotic use 2. Decreased pH ( acid) a. Carbohydrate malabsorption b. Fat malabsorption c. Disaccharidase deficiency
Random Collection
1. 2. 3. 4. 5. Universal precaution Collect stool in a dry,clean container uncontaminated with urine or other body secretions, such as menstrual blood Collect the stool with a clean tongue blade or similar object. Deliver immediately after collection
Interfering factors
1. Patients receiving tetracyclines, anti-diarrheal drugs, barium, bismuth, oil, iron , or magnesium may not yield accurate results. 2. Bismuth found in toilet tissue interferes with the results. 3. Do not collect stool from the toilet bowl.A clean, dry bedpan is the best. 4. Lifestyle, personal habbits, environments may interfere with proper sample procurement.
Normal values in stool Analysis
Macroscopic examination
Amount Colour Odour
Normal value
100-200 g / day Brown Varies with pH of stool and depend on bacterial fermentation Plastic, not unusual to see fiber, vegetable skins. Formed None
Ova and parasites collection
1. Warm stools are best for detecting ova or parasites. Do not refrigerate specimen for ova or parasites. 2. If the stool should be collect in 10 % formalin or PVA fixative, storage temperature is not critical. 3. Because of the cyclic life cycle of parasites, three separate random stool specimens are recommended.
Normal values
Undigested food
Meat fibers, Starch, Trypsin Eggs and segments of parasites Yeasts Leukocytes
None to small amount
None None None None
Normal values in stool analysis
Chemical examination
Chloride Potassium Lipids ( fatty acid)
Normal values
2.5-3.9 mEq / 24 hr 15.7-20.7 mEq /24 hr 0-6 g / 24 hr
Clinical Implications
1.Fecal consistency may be altered in various disease states
present in greater amounts in normal children. Osmolarity used 200-250 mOsm with serum osmolarity to calculate osmotic gap Sodium 5.8-9.8 mEq / 24hr
Normal values in stool Analysis
Stool Odor
Normal value: Varies with pH of stool and diet. Indole and sketole are the substances that produce normal odor formed by intestinal bacteria putrefaction and fermentation. Clinical implication A foul odor is caused by degradation of undigested protein. A foul odor is produced by excessive carbohydrate ingestion. A sickly sweet odor is produced by volatile fatty acids and undigested lactose
Enteric pathogen collection
1. Some coliform bacilli produce antibiotic substances that destroy enteric pathogen. Refrigerate specimen immediately. 2.A diarrheal stool will usually give accurate results. 3.A freshly passed stool is the specimen of choice. 4. Stool specimen should be collected before antibiotic therapy, or as early in the course of the disease. 5. If blood or mucous is present, it should be included in the specimen