[5] LESSON 10: FECALYSIS Flashcards
1
Q
Clinical Significance of Fecal Analysis
A
Early detection of GIT bleeding
Liver and biliary duct disorders
Maldigestion and malabsorption syndromes
Inflammation
Causes of diarrhea and steatorrhea
2
Q
DIARRHEA
Increase in daily stool weight above [?] (↑liquidity; frequency > 3x/day)
A
200 g
3
Q
DIARRHEA
Classification based on
A
(1) duration of illness, (2) mechanism, (3) severity and (4) stool characteristics
4
Q
DIARRHEA
Laboratory tests performed:
A
(1) fecal electrolytes, (2) fecal osmolality and (3) stool pH.
5
Q
Osmotic Gap
A
290 - [2 (fecal sodium + fecal potassium)]
6
Q
Increased secretion of water and electrolytes
A
Secretory
7
Q
Enterotoxin-producing bacteria
A
Secretory
8
Q
> 50 mOsm/kg
A
Secretory
9
Q
Incomplete breakdown or reabsorption of food
A
Osmotic
10
Q
Lactose intolerance, celiac sprue, poorly absorbed sugars, amebiasis
A
Osmotic
11
Q
< 50 mOsm/kg pH < 5.6
A
Osmotic
12
Q
Useful for the diagnosis of pancreatic insufficiency and small bowel disorders that cause malabsorption
A
STEATORRHEA
13
Q
Increase in stool fat (>6g/day)
A
STEATORRHEA
14
Q
Stool appears pale, greasy, bulky, spongy or pasty
A
STEATORRHEA
15
Q
: used to differentiate malabsorption from maldigestion
A
D-xylose Test
16
Q
: malabsorption
A
Low D-xylose
17
Q
: maldigestion (pancreatic insufficiency)
A
Normal D-xylose
18
Q
: suitable for qualitative testing for blood, and microscopic examination of leukocytes, muscle fibers and fecal fats
A
Random
19
Q
: for quantitative testing
A
3-Day Collection
20
Q
MACROSCOPIC SCREENING
A
COLOR
APPEARANCE
21
Q
Upper gastrointestinal bleeding
A
Black
22
Q
Lower gastrointestinal bleeding
A
Red
23
Q
Bile duct obstruction
A
Pale yellow, white, gray
24
Q
oral antibiotics
A
Green
25
Bile-duct obstruction
Bulky/frothy
26
Intestinal constriction
Ribbon-like
27
Colitis
Mucus/blood-streaked mucus
28
Dysentery
Mucus/blood-streaked mucus
29
Malignancy
Mucus/blood-streaked mucus
30
Constipation
Mucus/blood-streaked mucus
31
Pancreatic disorders
Bulky/frothy
32
Green vegetables
Green
33
Barium sulfate
Pale yellow, white, gray
34
Beets and food coloring
Red
35
Rifampin
Red
36
Iron therapy
Black
37
Charcoal
Black
38
Bismuth
Black
39
Fecal smears are examined for the presence of leukocytes (?), undigested muscle fibers and fats (?)
microbial diarrhea
steatorrhea
40
Neutrophils in feces indicates irritation of the intestinal mucosa in ulcerative colitis and bacterial dysentery
Fecal Leukocytes
41
Fecal Leukocytes
diarrhea is caused by invasive bacteria
PRESENCE
42
All smears or slide preparations must be performed on fresh specimens
Fecal Leukocytes
43
Fecal Leukocytes
faster to prepare, but more difficult to interpret
Wet Smears
44
Fecal Leukocytes
provide permanent slides for evaluation
Dry Smears
45
Fecal Leukocytes
Positive result:
3 neutrophils/HPF or any neutrophil/OIF
46
Fecal Leukocytes
stained with either Wright’s or Gram stain
Dry Smears
47
Fecal Leukocytes
stained with methylene blue
Wet Smears
48
Fecal Leukocytes
diarrhea is caused by toxin-producing bacteria
ABSENCE
49
Used in the diagnosis and monitoring of patients with pancreatic insufficiency, biliary obstruction and gastrocolic fistulas
Muscle Fiber
50
Patient Preparation: include red meat in their diet prior to collection
Muscle Fiber
51
Specimens should be examined within 24 hours of collection
Muscle Fiber
52
Muscle Fiber
Procedure: stool is emulsified in [?]
examine for [?]
10% alc. eosin
5 min
53
Muscle Fiber
Count number of [?] with well-preserved striations
red-stained fibers
54
: with visible striations (vertical and horizontal)
Undigested fibers
55
: with striations in one direction
Partially digested fibers
56
: no striations
Digested fibers
57
undigested fibers Significant Result:
>10 undigested fibers
58
Screening test for the presence of excess fecal fat
Qualitative Fecal Fat
59
Monitoring of patients undergoing treatment for malabsorption disorders
Qualitative Fecal Fat
60
Qualitative Fecal Fat
Makes use of lipid dyes:
(1) Sudan III, (2) Sudan IV and (3) Oil Red O
61
—readily stained by Sudan III and appear as large orange-red droplets
Neutral Fats/Triglycerides
62
[?]—steatorrhea
>60 droplets/hpf
63
—do not stain directly with Sudan III
Fatty Acid Salts and Fatty Acids
64
specimen must be mixed with HAc and heated
Fatty Acid Salts and Fatty Acids
65
size and number of fat droplets are noted
Fatty Acid Salts and Fatty Acids
66
Normal: [?] small fat droplets, [?] in size per hpf
100
<4um
67
Slightly Increased: [?] droplets, [?] in size per hpf
100
1 to 8 um
68
Increased: [?] droplets, [?] in size per hpf
100
6 to 75 um
69
—stained by Sudan III after heating and crystallizes during cooling
Cholesterol
70
Most frequently performed chemical screening test
Occult Blood
71
Occult Blood
Bleeding in excess of [?] stool is pathologically significant
2.5ml/150g
72
Used as a mass screening procedure for the early detection of colorectal cancer
Occult Blood
73
Occult Blood
Principle:
pseudoperoxidase activity of hemoglobin
74
Occult Blood Indicator Chromogens
Benzidine—most sensitive
Ortho-toluidine
Gum Guaiac—least sensitive; preferred for routine testing
75
Indicator Chromogens
Benzidine—most sensitive
Ortho-toluidine
Gum Guaiac—least sensitive; preferred for routine testing
76
—most sensitive
Benzidine
77
—least sensitive; preferred for routine testing
Gum Guaiac
78
Used as a confirmatory test for steatorrhea
Quantitative Fecal Fat
79
Patient preparation: regulated intake of fat (100g/dl)
Quantitative Fecal Fat
80
Quantitative Fecal Fat
Specimen required:
refrigerated 3-day specimen
81
Quantitative Fecal Fat
Normal values: [?] coefficient of fat retention
1 to 6 g/dl or at least 85%
82
Quantitative Fecal Fat Methods for Quantitation
Van De Kamer Titration
Gravimetric Method
83
—gold standard for fecal fat
Van De Kamer Titration
84
Distinguishes between fetal blood or maternal blood
APT Test
85
Sample: infant’s stool or vomitus
86
Control: cord blood and adult blood
87
Procedure
Sample emulsified in water to [?] centrifuged
[?] is added to the pink Hb containing supernatant
free Hb
1% NaOH
88
Fetal Hb—solution remains [?];
pink
89
Maternal Hb—
yellow-brown
90
Fecal Enzymes
Clinical significance
Pancreatic insufficiency
Steatorrhea
91
X-ray paper is exposed to the stool sample emulsified in water
Trypsin
92
—digestion of gelatin on the x-ray paper = clear area
Trypsin Presence
93
—inability to digest gelatin = no change
Trypsin Absence
94
Insensitive procedure and only detects severe cases
Trypsin
95
Trypsin
: proteolytic activity of bacterial enzymes
False (+)
96
Trypsin
: intestinal degradation of trypsin; inhibitors in feces
False (-)
97
More sensitive indicator of less severe cases of pancreatic insufficiency
Chymotrypsin
98
More resistant to intestinal degradation
Chymotrypsin
99
Remains stable in fecal samples for up to 10 days at room temp
Chymotrypsin
100
Measured spectrophotometrically
Chymotrypsin
101
Pancreas specific and a very sensitive indicator of exocrine pancreatic insufficiency
Elastase I
102
Easy to perform and requires only a single stool sample
Elastase I
103
Measured by immunoassay using the ELISA kit
Elastase I
104
Inability to reabsorb carbohydrates
(Celiac disease)
105
Lack of digestive enzymes
(lactose intolerance)
106
Detects congenital disaccharidase deficiency and enzyme deficiencies due to nonspecific mucosal injury
Copper Reduction Test (Clinitest)
107
Most valuable in assessing cases of infant diarrhea and may be accompanied by a pH determination
Copper Reduction Test (Clinitest)
108
normal stool pH: 7 to 8
Copper Reduction Test (Clinitest)
109
carbohydrate disorders = pH < 5.5
Copper Reduction Test (Clinitest)
110
Procedure: Clinitest tablet + emulsified sttol
Copper Reduction Test (Clinitest)
111
Copper Reduction Test (Clinitest) Result of 0.5g/dl =
carbohydrate intolerance
112
Performed after a positive fecal Clinitest
Serum carbohydrate intolerance test
113
—for malabsorption
Serum carbohydrate intolerance test
D-xylose
114
Lactose tolerance test—for maldigestion
Serum carbohydrate intolerance test
115
Microscopic count of neutrophils in smear stained with methylene blue, Gram or Wright’s stain
Examination of neutrophils
116
#/HPF indicates condition affecting intestinal wall
Examination of neutrophils
117
Microscopic examination of direct smear stained with Sudan III
60 large orange-red droplets indicates malabsorption
118
Microscopic examination of smear heated with HAc and Sudan III
100 orange-red droplets measuring 6 to 75 um indicates malabsorption
119
Pseudoperoxidase activity of Hb liberates O2 from H2O2 to oxidize Guaiac reagent
Occult blood
120
Blue color indicates gastrointestinal bleeding
Occult blood
121
Addition of H2O2 to Hb containing emulsion determines presence of maternal or fetal blood
APT test
122
Pink color indicates presence of fetal blood
APT test
123
Emulsified specimen placed on x-ray paper determines ability to digest gelatin
Trypsin
124
Inability to digest gelatin indicates lack of trypsin
Trypsin
125
Addition of Clinitest tablet to emulsified stool detects presence of reducing substances
Clinitest
126
Reaction of 0.5g/dl reducing substances suggests carbohydrate intolerance
Clinitest
127
shape of Type 2 stool
128
hidden blood
129
pale, greasy, bulky stool
130
detected by Dxylose
131
blood that appears pink
132
used for fecal carbohydrates
133
stain used for dry smears
134
muscle fiber counted microscopically
135
Stool color indicating upper GIT bleeding
136
very sensitive indicator of pancreatic insufficiency
137
testing that uses a 3day stool sample
138
type of diarrhea with osmotic gap > 50 mOsm/kg
139
fecal leukocyte examined microscopically
140
detected by lactose intolerance test
141
lipid readily stained in Sudan III
