FECALYSIS Flashcards
•An end product of body metabolism
Feces
•Produced by the intestines after reabsorption of necessary substances
Feces
Clinical Significance of Fecal Analysis
•Early detection of [?]
•[?] disorders
•[?] syndromes
•Inflammation
•Causes of[?]
GIT bleeding
Liver and biliary duct
Maldigestion and malabsorption
diarrhea and steatorrhea
•Increase in daily stool weight above 200 g
DIARRHEA
: less than 4 weeks
•Acute DIARRHEA
: >4 weeks
•Chronic DIARRHEA
↑liquidity; frequency > 3x/day
DIARRHEA
Incompletebreakdown or reabsorption of food
Osmotic Diarrhea
> Lactose intolerance
Osmotic Diarrhea
> Celiac sprue
Osmotic Diarrhea
> Malabsorptionof sugar
Osmotic Diarrhea
> Amebiasis
Osmotic Diarrhea
> Antibiotic administration
Osmotic Diarrhea
> 50 mOsm/kg
Osmotic Diarrhea
<60 mmol/L
Osmotic Diarrhea
<5.3
Osmotic Diarrhea
Increased secretion of water and electrolytes
Secretory Diarrhea
> Enterotoxinproducing bacteria
Secretory Diarrhea
> Drugs,laxatives
Secretory Diarrhea
> Inflammatory bowel disease
Secretory Diarrhea
> Endocrine disorders
Secretory Diarrhea
<50 mOsm/kg
Secretory Diarrhea
> 90 mmol/L
Secretory Diarrhea
> 5.6
Secretory Diarrhea
•Increase in stool fat (>6g/day)
STEATORRHEA
•Useful for the diagnosis of pancreatic insufficiency and small bowel disorders that cause malabsorption
STEATORRHEA
•Stool appears pale, greasy, bulky, spongy or pasty
STEATORRHEA
: used to differentiate malabsorptionfrom maldigestion
•D-xylose Test
Low D-xylose:
malabsorption
Normal D-xylose:
maldigestion(pancreatitis)
: suitable for qualitative testing for blood, and microscopic examination of leukocytes, muscle fibers and fecal fats
Random
: for quantitative testing
3-Day Collection
•Specimen Containers
•Type and Amount Collected
•Contaminants to Avoid
•Gas Formation
Upper gastrointestinal bleeding
Black
Ingestion of iron,charcoal,bismuth
Black
Lower gastrointestinal bleeding
Red
Beets and foodcoloring
Red
Rifampin
Red
Bile duct obstruction
Pale yellow,white, gray
Diagnostic procedures that use barium sulfate
Pale yellow,white, gray
Biliverdin/oral antibiotics
Green
Green vegetables
Green
Separate hard lumps, like nuts (hard to pass)
Type 1
Sausage-shaped, but lumpy
Type 2
Sausage-shaped, but with cracks on surface
Type 3
Sausage or snake like, smooth and soft
Type 4
Soft blobs with clear-cut edges (easy to pass)
Type 5
Fluffy pieces with ragged edges, mushy
Type 6
Watery, no solid pieces (entirely liquid)
Type 7
Fecal smears are examined for the presence of leukocytes (?), undigested muscle fibers and fats (?)
microbial diarrhea
steatorrhea
indicates irritation of the intestinal mucosa in ulcerative colitis and bacterial dysentery
Neutrophils in feces
PRESENCE : diarrhea is caused by
invasive bacteria
ABSENCE: diarrhea is caused by
toxin-producing bacteria
All smears or slide preparations must be performed on
fresh specimens
Types of Smears
Wet Smears
Dry Smears
faster to prepare, but more difficult to interpret; stained with methylene blue
Wet Smears
provide permanent slides for evaluation; stained with either Wright’s or Gram stain
Dry Smears
Fecal Leukocytes Positive result:
3 neutrophils/HPF or any neutrophil/OIF
Used in the diagnosis and monitoring of patients with pancreatic insufficiency, biliary obstruction and gastro colic fistulas
Muscle Fiber
Patient Preparation: include red meat in their diet prior to collection
Muscle Fiber
Specimens should be examined within
24 hours of collection
Procedure:
1.Stool is emulsified in [?] —> examine for [?]
2.Count number of [?] with well-preserved striations
10% alcoholic eosin
5 min
red-stained fibers
: with visible striations (vertical and horizontal)
-Undigested fibers
: with striations in one direction
-Partially digested fibers
: no striations
-Digested fibers
Muscle Fiber Significant Result:
> 10 undigested fibers
•Screening test for the presence of excess fecal fat
Qualitative Fecal Fat
•Monitoring of patients undergoing treatment for malabsorptiondisorders
Qualitative Fecal Fat
Qualitative Fecal Fat makes use of lipid dyes:
(1) Sudan III, (2) Sudan IV and (3) Oil Red O
—readily stained by Sudan III and appear as large orange-red droplets
Neutral Fats/Triglycerides
Neutral Fats/Triglycerides —steatorrhea
> 60 droplets/hpf
—do not stain directly with Sudan III
Fatty Acid Salts and Fatty Acids
—stained by Sudan III after heating and crystallizes during cooling
Cholesterol
-Specimen must be mixed with HAcand heated
Fatty Acid Salts and Fatty Acids
-Size and number of fat droplets are noted
Fatty Acid Salts and Fatty Acids
Fatty Acid Salts and Fatty Acids Normal:
100 small fat droplets, <4um in size per hpf
Fatty Acid Salts and Fatty Acids Slightly Increased:
100 droplets, 1 to 8 um in size per hpf
Fatty Acid Salts and Fatty Acids Increased:
100 droplets, 6 to 75 um in size per hpf
CHEMICAL EXAMINATION TESTS
1.Fecal Occult Blood Test
2.Quantitative Fecal Fat
3.Alkali Denaturation Test
4.Fecal Enzymes
5.Carbohydrates
•Most frequently performed chemical screening test
Fecal Occult Blood Test
In Fecal Occult Blood Test, bleeding in excess of [?] stool is pathologically significant
2.5ml/150g
Used as a mass screening procedure for the early detection of colorectal cancer
Fecal Occult Blood Test
Fecal Occult Blood Test Principle:
pseudoperoxidase activity of hemoglobin
Fecal Occult Blood Test Indicator Chromogens:
Benzidine
Ortho-toluidine
Gum Guaiac
: most sensitive
Benzidine
: least sensitive
Gum Guaiac
; preferred for routine testing
Gum Guaiac
False positive: Guaiac-Based Fecal Occult Blood Tests
Turnips, cauliflower, fish, meat, bananas, apples, aspirin
False negative: Guaiac-Based Fecal Occult Blood Tests
Ascorbic acid
•Used as a confirmatory test for steatorrhea
Quantitative Fecal Fat
Quantitative Fecal Fat
•Patient preparation: regulated intake of fat (?)
100g/dl
Quantitative Fecal Fat
•Specimen required:
refrigerated 3-day specimen
Quantitative Fecal Fat
•Normal values: [?] or at least [?] coefficient of fat retention
1 to 6 g/dl
85%
Methods for Quantitation
1.Van De KamerTitration
2.Gravimetric Method
—gold standard for fecal fat
1.Van De KamerTitration—
•Distinguishes between fetal blood or maternal blood
APT Test (Fetal Hemoglobin)
APT Test (Fetal Hemoglobin) Sample:
infant’s stool or vomitus
APT Test (Fetal Hemoglobin) Control:
cord blood and adult blood
APT Test (Fetal Hemoglobin) Procedure
-Sample emulsified in water to [?] —> centrifuge
-[?] is added to the pink Hbcontaining supernatant
free hb
1% NaOH
APT Test (Fetal Hemoglobin) Result:
—solution remains pink
— yellow-brown
Fetal Hb
Maternal Hb
—solution remains pink
— yellow-brown
Fetal Hb
Maternal Hb
Fecal Enzymes Clinical significance
•Pancreatic insufficiency: Chronic pancreatitis, cystic fibrosis
•Steatorrhea
-X-ray paper is exposed to the stool sample emulsified in water
- Trypsin/GELATIN TEST
-Insensitive procedure and only detects severe cases
- Trypsin/GELATIN TEST
Trypsin/GELATIN TEST
Presence—digestion of gelatin on the x-ray paper =
clear area
Trypsin/GELATIN TEST
Absence—inability to digest gelatin =
no change
Fecal Enzymes False (+):
proteolyticactivity of bacterial enzymes
Fecal Enzymes False (-):
intestinal degradation of trypsin; inhibitors in feces
-More sensitive indicator of less severe cases of pancreatic insufficiency
Chymotrypsin
-More resistant to intestinal degradation
Chymotrypsin
-Remains stable in fecal samples for up to 10 days at room temp
Chymotrypsin
-Measured spectrophotometrically
Chymotrypsin
-Pancreas specific and a very sensitive indicator of exocrine pancreatic insufficiency
Elastase I
-Easy to perform and requires only a single stool sample
Elastase I
-Measured by immunoassay using the ELISA kit
ElastaseI
•Valuable assessment of infantile diarrhea
Carbohydrates
•Accompanied by pH determination
Carbohydrates
Carbohydrates
-Normal:
7-8
Carbohydrates
-Increased fermentation:
5.5
-Detects congenital disaccharidase deficiency
Copper reduction Test
Copper reduction Test
[?] —> Carbohydrate intolerance
-0.5g/dl
Serum carbohydrate intolerance test
a. [?]: for malabsorption
b. [?]: for maldigestion
D-xylose
Lactose tolerance
