2. DEFINITION
Stool examination by Dr. Priyanka
Buragohain
2
• Human feces is called as stool.
• faeces / feces is plural of latin term faex
meaning RESIDUE.
• It is the waste residue of indigestible materials
of an animal’s digestive tract expelled through
the anus during defecation.
• Meconium is newborn’s first feces.
• SCATOLGY or CAPROLOGY is the study of
feces.
3. COMPOSITION
Stool examination by Dr. Priyanka
Buragohain
3
• ¾ water, ¼ solid
• Undigested and unabsorbed food
• Intestinal secretions, mucous
• Bile pigments and salts
• Decomposed products
• Bacteria and inorganic material
• Epithelial cells, leukocytes.
4. PRECAUTION BEFORE COLLECTION
Stool examination by Dr. Priyanka
Buragohain
4
• Patient should avoid the following things for at
least 48 hours before collection of stool:
• Mineral oils, bismuth, non absorbable anti
diarrhoeal drugs, antimalarial drugs, antibiotics,
etc
• Pt. Should not have barium swallow examination
before stool R/E
• Avoid iron containing drugs, meat, fish etc for
atleast 48 hours before stool for occult blood.
• In constipated patients use only non residual
purgative
5. COLLECTION
Stool examination by Dr. Priyanka
Buragohain
5
• Universal precautions
• Pt. is asked to pass stool in a clean container.
• Stool should be collected in a steralized, wide mouthed container.
• Loose/last/portion containing mucus, blood etc is to be collected
in a wide mouthed bottle.
• Should be uncontaminated with urine or any other body
secretions.
• >2gm is required.
• Properly named and always a fresh sample should be tested.
• Liquid stool to be examined within ½ hour
• Solid stool to be examined within 1 hour.
• If delayed store in a refrigerator.
6. COLLECTION CONTD...
Stool examination by Dr. Priyanka
Buragohain
6
• 3 samples of stool within 10 days to exclude
false negatives.
• 2 samples to be examined on alternate days
after normal defaecation and 1 sample after a
purgative for certain worms.
• Formalin is the best preservative. It kills the
bacteria but ptreserves the protozoa and
helminthes.
• For culture no preservatives to be used
10. MACROSCOPIC EXAMINATION
Stool examination by Dr. Priyanka
Buragohain
10
AMOUNT
• Normal is 150 g to 200 g/day
• Increased in steatorrhoea, diarrhoea, indigestion
of carbohydrate.
11. CONSISTENCY OR FORM
Stool examination by Dr. Priyanka
Buragohain
11
• Normal is soft but formed
• Excessively hard/scybala- habitual constipation
• Flattened or ribbon like-intake of excess of
mineral oil, carcinoma of rectum, stricture of
rectum
• Soft, mushy, liquid and voluminous- diarrhoea,
intake of purgatives
• Small numerous, largely mucus and blood with
small amount of stool- dysenteries
• Rice watery without fecal matter- Cholera
13. Colour
Stool examination by Dr. Priyanka
Buragohain
13
• Dark Grey- excessive cocoa or chocolate
ingestion
• Reddish or blackish brown- large amount of
fruits
• Green – ingestion of green leafy vegetables,
administration of calomel due to biliverdin
• Red – Beat ingestion fresh blood
• Yellow – rhubarb or senna ingestion, normal
stool
14. Stool examination by Dr. Priyanka
Buragohain
14
• Clay – obstructive jaundice, barium meal x-ray
• Tarry black – haemorrhage in stomach/upper
intestine
• Dark brown to bright red – bleeding in rectum
or sigmoid colon
• Red streaks of blood on the surface of faeces-
haemorrhoids, fissures, carcinoma ,ulcerative
colitis
15. Odour
Stool examination by Dr. Priyanka
Buragohain
15
• Normal odour is aromatic due to indole and
skatole
• Increased- excessive protein ingestion
• Sour rancid- fatty acid in milk indigestion (in
children and adults), normal in infants
• Putrid- severe diarrhoea of malignancy,
gangrenous dysentry
16. Reaction
Stool examination by Dr. Priyanka
Buragohain
16
• Normal is neutral
• Ph varies from 6.9 to 7.2
• pH is dependent on bacterial fermentation
and putrefaction in the bowel.
• Alkaline – excess protein ingestion
• Acidic – excess carbohydrate ingestion
17. Mucus
Stool examination by Dr. Priyanka
Buragohain
17
• Small quantity of mucin is normal
• Small quantity – faeces from small gut
• Excessive quantity – infection of intestine
• Entirely mucus with little or no faeces and
streaks of blood- dysentery, ileo colitis,
intussusception
18. Concretion
Stool examination by Dr. Priyanka
Buragohain
18
• In infants whitish curds may be found
• Gall bladder stones may be rarely found
19. Blood
Stool examination by Dr. Priyanka
Buragohain
19
• Absent in normal faeces
• Formed stool with streaks of blood – lesion in
sigmoid colon, rectum or anal canal
• Liquid stool with bright red blood, pus and
mucus- bacillary dysentery, ulcerative colitis
• Semi formed stool with deep tarry black
blood- melena
• Loose stool with deep cherry red blood-
melena
20. Pus
Stool examination by Dr. Priyanka
Buragohain
20
• Normally absent
• Pus with blooded mucus- ulcerative colitis,
bacillary dysentery, ulcerative carcinoma
21. Stool examination by Dr. Priyanka
Buragohain
21
• GROSS FOOD REMNANTS MAY IN NORMAL
STOOL
• UNDIGESTED TABLETS MAY BE FOUND
23. Chemical Examination Of Stool
Stool examination by Dr. Priyanka
Buragohain
23
• Acidity/basicity
• Fats
• Nitrogen
• Stercobilinogen
• Coproporphyrin
• Occult blood
• Reducing substances
• N. B : most commonly used chemical
examination of stool is pH, occult blood and
reducing substances
24. Stercobilinogen
Stool examination by Dr. Priyanka
Buragohain
24
• Normal is 40 to 280 mg/day
• Average is 150 mg/day
• Dependent on amount of bilirubin passing to
intestine(jaundice)
25. Occult blood
Stool examination by Dr. Priyanka
Buragohain
25
• Detect blood which is present in amount or form
not visible macroscopically
• Normally nil
• Abnormal presence in condition of occult
haemorrhage in the GI tract
• BENZIDINE TEST
• GUAIAC TEST
• ORTHOTOLIDINE TEST
• Most commonly used test is benzidine test
26. Stool examination by Dr. Priyanka
Buragohain
26
BENZIDINE TEST
• 4 gm benzidine in 100 ml of glacial acetic acid
• Emulsify pea sized bit of faeces in 5 ml of
water.
• Mix 1 ml emulsion and 1 ml of reagent in test
tube
• Add several drops of 35 H2O2
• Blue colour indicates positive reaction
27. • Trace- faint blue colour after 1
min
• 1+ - definite blue green slowly
• 2+ - green blue rapidly
• 3+ - blue almost immediately
• 4+ - dark blue immediately
Stool examination by Dr. Priyanka
Buragohain
27
28. GUAIAC TEST
• Less sensitive
• With loss of 20 to 30 ml of
blood all test will be positive
• Guaiac reagent consist of 1 gm
Guaiac in 5 ml of 95% ethanol.
• Make a small smear of feces on
a filter paper
• Add 2 to 3 drops of gum guaiac
solution +
2 to 3 drops of glacial acetic acid
+ 2 to 3 drops of 3% H2O2
Stool examination by Dr. Priyanka
Buragohain
28
29. • Trace- faint blue green in 1 min
• 1+ light blue slowly
• 2+ clear blue rapidly
• 3 + deep blue almost immediately
• 4+ deep blue immediately
Stool examination by Dr. Priyanka
Buragohain
29
30. Stool examination by Dr. Priyanka
Buragohain
30
ORTHOTOLIDINE TEST
• Intermediate sinsitivity
• Smear the stool on a filter paper with an
applicator
• Pipette a few drops of the reagent on to the
filter paper(orthotolidine barium peroxide 200
mg+ glacial acetic acid 5 ml)
• After 30 sec examine for a blue colour
• Blue green colour within 30 sec means
positive test
31. Stool examination by Dr. Priyanka
Buragohain
31
Interpretation
• Gastric disease eg chronic ulcer and
malignancy
• Intestinal diseases eg dysentery, typhoid fever,
carcinoma
• Haemorrhoids
• During instrumentation
32. Faecal reducing substance test
Stool examination by Dr. Priyanka
Buragohain
32
• To diagnose lactose intolerance
• Sample of 5 gm stool is needed
• Sample needs to be delivered to the
laboratory as soon as possible, preferably
within 1 hr , cause lactose in the stool will
normally be broken down by chemical
processes within 2-4 hrs after the specimen is
produced.
33. Stool examination by Dr. Priyanka
Buragohain
33
Interpretation
• Negative/ trace- < 0.25 g/dl
• Suspicious(grade 1) – 0.25-0.5 g/dl
• Abnormal(grade 2-4)->0.5 g/dl
• Found in Carbohydrate malabsorption
• Tropical sprue
35. Stool examination by Dr. Priyanka
Buragohain
35
NEED FOR MICROSCOPIC EXAMINATION
• For the diagnosis of microscopic elements.
• Trophozoites and its movements are better seen
in unstained preparation of a fresh material.
• Cystic forms &Nuclear character are better seen
in stained preparation(iodine)
• Gycogen mass- stained with iodine
• Chromatoid bars- unstained preparation
• N.B – Both stained and unstained materials are
to be prepared
37. Stool examination by Dr. Priyanka
Buragohain
37
Need of concentration technique
• To see whether treatment of parasite is
successful
• To find ova of S. Mansoni or Taenia if few or
other ova and cyst are not seen in routine
examination
• To examine stool specimens from patients
who do not come from an area where a
particular parasite is found
39. Stool examination by Dr. Priyanka
Buragohain
39
FLOATATION TECHNIQUE
• Use solutions which have highier specific
gravity(zinc sulphate or Sheather’s sugar) than
the organisms to be floated so that the organisms
rise to the top and the debries sink to the
bottom.
• Advantage – produce a cleaner material than the
sedimentation technique
• Disadvantage – walls of eggs and cyst will often
collapse, hindering identification.
• Some parasite eggs do not float.
40. SEDIMETATION TECHNIQUE
• Use solutions of lower specific
gravity than the parasitic
organisms(formalin ethyl
acetate technique)
• Recommended for general
diagnostic laboratories due to
easy to perform and less prone
to technical error.
Stool examination by Dr. Priyanka
Buragohain
40
41. Sedimentation techniques
Stool examination by Dr. Priyanka
Buragohain
41
• Mix a small piece of stool with 10 ml of water or saline in a tube/ bottle
• Sieve the suspension into a beaker through a strainer with small holes.
• Pour the contents into a centrifuge tube
• Centrifuge at 2000-3000/rpm for 1 min
• Pour off the supernatant part
• Resuspend the deposit in clean water and add enough water to fill the
tube.
• Mix well and recentrifuge
• Pour off the supernatant part
• Resuspend in zinc sulphate solution, fill the tube with the solution
• Centrifuge at high speed for 1 min
• Transfer the contents from the surface of the tube to a slide, using a
bacteriological wire loop
• Add small drops of saline and mix
• Cover with a cover slip
• Examine under 10x and 40x objectives
46. Iodine wet mount
Stool examination by Dr. Priyanka
Buragohain
46
• Iodine kills the organisms, therefore
motility is lost.
• Used mainly to stain nuclei and
glycogen mass if present.
• Flagella becomes recognisable.
• Cyst can usually be specifically
identified in this method.
• Lugol’s iodine solution is used.
47. Stool examination by Dr. Priyanka
Buragohain
47
Lugol’s iodine
• Its very strong
• Must be diluted about 5 times with distilled water
• Stain deteriorates quickly hence to be prepared every 2
weeks
• Contains:
Iodine crystals(powdered): 5 g
Potassium iodide
Distilled water
:10 g
: 10
• Potassium iodide is dissolved in distilled water and
iodine crystals are slowly added. Solution is filtered and
kept in a stoppered bottle of amber colour
48. Buffered methylene blue wet mount
• Stains only trophozoites of
amoeba
• It does not stain amoebic
cyst or trophozoites and cyst
of flagellates.
• Nucleus and the inclusions
such as RBC or yeast cells
stain dark blue
• Cytoplasm stains light blue
Stool examination by Dr. Priyanka
Buragohain
48
49. Eosin wet mount
• Detection of trophozoites
and cyst
• They can be much more
easily detected against
the pink- red background
of eosin preparation
Stool examination by Dr. Priyanka
Buragohain
49
56. Stool examination by Dr. Priyanka
Buragohain
56
microscopic examination findings
• REMNANTS OF FOOD
• vegetable cells
• Muscle fibres
• Starch granules
• Fat globules
• Connective tissue/ elastic
fibres
• Mineral oil or castor oil
globules
• CELLS
• Epithelial cells
• Pus cells
• Macrophages
• Ghost cells
• Pyknotic bodies
• Eosinophills
• RBC
• Crystals
• Yeasts and molds
• Protozoa
• Helminthic parasites
57. Vegetable cell
• Sometimes causes
confusion with ova,
eggs, cyst or cell bodies
• IRREGULAR OUTER
MARGIN
Excess quantity is seen in
excess intake of
vegetables or
indigestion
Stool examination by Dr. Priyanka
Buragohain
57
58. Stool examination by Dr. Priyanka
Buragohain
58
Muscle fibres
• May confuse with Tinea segments
• Excess protein intake or indigestion
• Its excess excretion is called
Creatorrhoea(flesh-flow)
59. Starch granules
• Variable in size, round to
polygonal in shape,
colourless, circular or Y
shaped dot in the centre
• Confused with ova of
helminths
• Found in carbohydrate
dyspepsia
• Better seen in iodine
preparation
Stool examination by Dr. Priyanka
Buragohain
59
60. Fat globules
• Appear similar to parasitic
cyst or cell bodies
• Emulsifying agents are
used to eliminate
confusion
• Confused with ova of
helminths
• Found in fat dyspepsia
Stool examination by Dr. Priyanka
Buragohain
60
61. Stool examination by Dr. Priyanka
Buragohain
61
Connective tissue/elastic fibres
• Confused with tinea
segments
• Signify indigestion
62. Stool examination by Dr. Priyanka
Buragohain
62
Mineral oil/ castor oil globules
• When taken as purgative
• May be confused with ova of helminthes
63. Epithelial cells
• Excess presence due to
inflammatory
conditions of colon,
rectum, anal canal
Stool examination by Dr. Priyanka
Buragohain
63
64. Pus cells
• Commonly found in
normal stool, help to ease
the passage of stool
• Normally not visible to
human eye.
• If visible indicates disease
• Bacillary dysentery, UC,
acute Amoebic dysentery,
malignancy of rectum,
drug induced enterocilitis
Stool examination by Dr. Priyanka
Buragohain
64
65. Macrophages
• Large mononuclear cells
with vesicular nucleus
and ingested materials
including RBC
• Confused with E.
Histolytica cyst or E. Coli
cyst
• Excess in Amoebic or
bacillary dysentery
Stool examination by Dr. Priyanka
Buragohain
65
66. Stool examination by Dr. Priyanka
Buragohain
66
Ghost cells
• Degerative form of
macrophages, epithelial
cells
• Its an enlarged/swollen
eosinophilic epithelial
cell with only
eosinophilic
cytoplasmic outline but
without a nucleus
• Characteristic of
bacillary dysentery
67. Stool examination by Dr. Priyanka
Buragohain
67
Pyknotic bodies
• Nuclear remains of
tissue cells and
leucocytes
• Characteristic of acute
amoebic dysentery
68. Stool examination by Dr. Priyanka
Buragohain
68
Eosinophils
• In intestinal allergy
• Diluting fluid used- Randolph’s diluting
fluid,Pilot’s stain
• Carbol chromotrope technique
• A measured quantity of the deposit is taken and
diluted with the diluting fluid 1:10 or 1: 20
according to the concentration of the residue and
counted in haemocytometer.
• Increased in allergic conditions, parasitic
infestation and drug allergy, ulcerative colitis
69. Stool examination by Dr. Priyanka
Buragohain
69
RBCs
• seen in cases of ulcrative lesions of gut
• in bacillary dysentery – yellowish discrete
• Amoebic dysentery – greenish and in clumps
71. • Charcot Leyden crystal:
• Slender and pointed at both ends,
Hexagonal bipyramidal structures
localised in the primary granues of
cytoplasm of eosinophils and
basophils
• Evidence of parasitic infiltrate eg
amoeba, ascaris, hookworm, fasciola
• diamond shaped or whetstone
shaped crystals
• Normally colourless, stained purplish-
red by trichome
• Vary in size and may be as large as 50
µm in length
• Found in UC, dysentery, malignant
ulcers, schistosomiasis etc
Stool examination by Dr. Priyanka
Buragohain
71
72. • Haematoidin crystals:
• Ironless pigment derived from
haemoglobin and formed within
tissues(reticuloendothelial cells)
but found extracellularly after 5-7
days in foci of previous
haemorrhage.
• Occurs as refractile, yellow- brown
and orange-red granules
• Characteristically as rhomboid
plates arranged in a radial pattern,
so called hematoidin burrs.
Stool examination by Dr. Priyanka
Buragohain
72
73. Yeast and molds
• Yeast are normally
present
• Excess in cases of AIDS
• Molds are rare but may
be seen in
immunodeficiency
conditions
Stool examination by Dr. Priyanka
Buragohain
73
78. Entamoeba histolytica
TROPHOZOITE STAGE
• Identified by motility and
presence of ingested RBC
• Shape : constantly changing
position
• Size :ranges from 18 to 40 µm
,average being 20 to 20 µm
• Cytoplasm :divisible in two
portion
• Nucleus :spherical in shape
Stool examination by Dr. Priyanka
Buragohain
84
79. Stool examination by Dr. Priyanka
Buragohain 85
RBC appear yellowish green inside the
endoplasm
Nucleus is not visible but a faint outline may be
detected
Endoplasm shows bluish or ground glass
appearance
Eccentric nucleus with karyosome (a small dot
at the centre surrounded by a clear halo),
nuclear membrane,
Linen network having a spoke like radial
arrangement
80. PRE CYSTIC STAGE
• Size :small in size,10 to 20
µm
• Shape :round or slightly
ovoid with blunt
pseudopodium
• Free from ingested RBC and
other materials
• Nucleus : large nucleus
• Retains the characteristics
of trophozoite.
Stool examination by Dr. Priyanka
Buragohain
80
81. CYSTIC STAGE
• Size : 6 to 9 µm / 12 to 15
µm
• Shape : round, surrounded
by a highly refractile
membrane called cyst wall
• Nucleus :quadrinucleate
• Clear and hyaline cytoplasm
• Nuclear structure retainning
the character of trophozoite
Stool examination by Dr. Priyanka
Buragohain
81
82. Stool examination
Burago
by Dr. Priyanka
hain
88
Saline mounting
•Chromatid bodies are seen as round
refracile bars
•Cyst wall smooth and thin
•Glycogen bar not visible
•Outlines of nuclei may be visible
•Iodine mounting
•Body of the parasite stains yellow to light
brown
•Nucleus is clearly seen with a karyosome
•Cytoplasm is smooth and hyaline
appearance
•Glycogen mass stains brown
Iron haematoxillin stain
•Chromatid body and nucleus stain jet
black
•Cytoplasm stains bluish or greyish
•Glycogen mass gets dissolved in the
process of stainning and remains as a
vacuole
83. Entamoeba coli
Stool examination by Dr. Priyanka
Buragohain
83
TROPHOZOITE STAGE
• Largest amoeba 20-40 µm in diameter
• Sluggishly motile
• Cytoplasm not clearly defined
• Opaque endoplasm packed with food
vacuoles with bacteria and others but
no RBC
• Nucleus visible in unstainned
preparation
• In stainned prep nucleus shows large
eccentric karyosome surrounded by
broader halo and coarse chromatin
ranules linning nuclear membrane
84. • CYST
• 15- 20 µm in diameter
• Rounded body
• Octanucleate
• Largen glycogen mass in
binucleate stage
• Chromatoid body if present
are in slender filaments or
pointed threads
• Glycogen mass and
chromatoid bodies are absent
in mature cyst
Stool examination by Dr. Priyanka
Buragohain
84
85. Endolimax nana
• Commensal in large intestine of
man
• Trophozoites are smaller in
size(8-9 µm in diameter)
• Sluggish in motility
• Cytoplasmic inclusions contain
bacteria and food particles but
no RBC
• Nucleus has irregular karyosome,
eccentric and in contact with
nuclear membrane
Stool examination by Dr. Priyanka
Buragohain
85
86. CYST
• Cyst are oval
• Same size as the
trophozoites
• Number nuclei are 1-4
• Mature cyst are
quadrinucleate
• Chromatoid bodies and
glycpgen mass are not seen
Stool examination by Dr. Priyanka
Buragohain
86
89. Stool examination by Dr. Priyanka
Buragohain
95
OTHER NON PATHOGENIC AMOEBIDA SPECIES
Trophozoite of E. hartmani
Trophozoite of Iodamoeba butschlii
Cyst of blastocystis hominis
90. Stool examination by Dr. Priyan ka 96
Balantidium coli
•Largest protozoal parasite
•Pig is the common reservoir
•Two stages
•Trophozoite and encysted stage
TROPHOZOITE
•Oval body
•60-70 µm in length and 40-50 µm breadth
•Body is covered with a delicate pellicle showing
longitudinal striations
•Cilia are short and delicate, of uniform length, on mouth
are longer called adoral cilia
•Thin layer of ectoplasm and granular endoplasm
•Groove at the anterior end(peristome) leading to a
mouth(cytostome) terminating in a short funnel shaped
gullet(cytopharynx) extending upto 1/3rd of the body
•At the posterior part permanent anus called cytophage is
situated
•2 nuclei: kidney shaped macronucleus, round
micronucleus in the concavity of micronucleus
•2 contractile vacuole, many food vacuole
Buragohain
91. CYST
• Smaller than trophic, 50-60
µm in diameter
• Cytoplasm is granular
contains the macronucleus,
micronucleus, refractile
body
• Contractile vacuole
• Thick transparent double
layered wall
Stool examination by Dr. Priyanka
Buragohain
91
92. Giardia lambia
• TROPHOZOITE
• Flat view: a tennis or badminton racket
• Side view: longitudinally split pear
• Dorsal surface is convex and the ventral
surface in concave with a sucking disc
• Size is 14 × 7 µm
• Anterior end is broad and rounded,
posterior end tapers to a sharp point
• Bilaterally symmetrical and all organs are
paired.
• 2 axostyles, 2 nuclei, 4 pairs of flagella
Exist in 2 phase: trophozoite and cyst
Stool examination by Dr. Priyanka
Buragohain
92
93. CYST
• Oval in shape
• Size is 12 × 7 µm
• Axostyle lie diagonally like dividing wall
within the cyst wall
• 4 nuclei lie clustered at one end, lie in
pairs at opposite poles
• Remains of flagella and sucking disc
may be seen in cytoplasm
• Acid causes the parasite to encyst
Stool examination by Dr. Priyanka
Buragohain
93
98. Taenia solium
• Segments of Tape worm or single
segment may be found
• White in colour, semi transparent.
• May be 3 – 10 m long/ 1-3 cm
segments maybe upto 24 m
• Variable length(1000-2000
proglottids)
• When stool is allowed to dry up
the pieces of segments will roll
upand appear as round worm,
moistening the segments will
restore the shape
• Head is quadrate in outline, has 4
circular suckers
• Head is absent of
rostellum/hooklets
Stool examination by Dr. Priyanka
Buragohain
98
99. Eggs of T. saginata
• Spherical and brown in colour
• 31-43µm in diameter
• Thin outer transparent
shell(remnants of yolk mass),
causes egg to clump together
• Inner embryophore is brown,
thick walled, radially striated
• Contains an oncosphere(14-
20µm), with 3 pairs of hooklets
• Doesnot float in saturated
solution of common salt
Stool examination by Dr. Priyanka
Buragohain
99
100. Taenia solium
• 2-3 metres long(800-900
proglottides)
• Scolex is 1mm in diameter,
globular in outline, 4 circular
suckers,
• Head with rostellum armed
with a double row of alternating
large and small hooklets,
shaped like daggers or Arabian
poniards
• Segments are shed in chains of
5-6 at a time, not single.
Stool examination by Dr. Priyanka
Buragohain
100
101. • EGGS
• Same as T. Solium
• 30x40 µm sized egg
• Pale yellow
• Thick radially striated
embryophore with 6
hooklets inside
Stool examination by Dr. Priyanka
Buragohain
101
102. Echinococcus granulosus
• Commonly called dog
tapeworm/ hydatid worm
• Man harbours the larval form,
not the adult
• Larva found wiyhin the hydatid
cyst, scolex of the future adult
worm remains invaginated
within a vesicular body.
Stool examination by Dr. Priyanka
Buragohain
102
104. Gastrodiscoides hominis
• Prevalent in Assam and Bengal
• Pyriform in shape
• Measures 5-10 mm × 4-6 mm
• Body has 2 parts: anterior conical and
posterior hemispherical portion which
is hollowed out ventrally to form a
concave disc
• Acetabulum is postero terminal,
situated ventrally
• Notch at posterior end
• Eggs are ovoid, operculated, 130×60
µm, immature when oviposited
Stool examination by Dr. Priyanka
Buragohain
104
105. Fasciola hepatica
• Eggs
• Large, operculated, ovoid , brownish
yellow(bile stained)
• Size is 140× 80 µm
• Contains a large unsegmentad ovum
in a mass of yolk cells
• Excreted with bile into duodenum
and then passed out along with the
faeces
• Does not float in saturated common
salt sol.
• Can develop only in water
Stool examination by Dr. Priyanka
Buragohain
105
106. Fasciola buski
• Reported in Assam, bengal,
china, thailand and other
oriental regions
• Largest trematode(2-7.5 length,
8-20 mm bredth, 0.5-3 mm
thickness)
• Elongated and oval in shape
• Resembles F. Hepatica but does
not possess any cephalic cone
• Each worm lay 25,000 eggs per
day
• Eggs are indistinguishable from
F. hepatica
Stool examination by Dr. Priyanka
Buragohain
106
107. Clonorchis sinensis
EGGS
• Yellowish brown
• Flask shaped
• Operculated
• Possess a terminal hook like
spine(resembling an electric bulb)
• Small in size(35×20µm)
• Ciliated embryo (oviposited stage)
• Do not float in saturated solution
of common salt
Stool examination by Dr. Priyanka
Buragohain
107
108. Paragonimus westermani
• Golden brown in colour
• Oval in shape with flattened
opercula
• 80- 55 µm
• Each egg contains an
unsegmented ovum
surrounded by yolk cells
• Prevalent in Assam
• Found in sputum and faeces
Stool examination by Dr. Priyanka
Buragohain
108
109. Ascaris lumbricoids
• Large round worms may
be males and females
or both
• Pinkish in colour
• 0.3-0.4 cm in thickness
• 15-25 cm long
• Males are shorter than
females
• Have curved tapering
tail
Stool examination by Dr. Priyanka
Buragohain
109
110. • UNFERTILISED EGGS
• Do not float on floatation method
• Size- 40×70 µm
• Yellow in colour
• Elongated
• Mammilated thin shell, ovum
containing refractile yolk globules
occupying the whole inside space
• May be confused with veg cell
• FERTILISED EGGS
• Float on floatation method
• Size- 40×70 µm
• Yellow in colour
• Oval or round
• Thick mammillated coat and
single celled ovum inside
Stool examination by Dr. Priyanka
Buragohain
110
111. Enterobius vermicularis
• Small round worm or thread
like worm or pin
worm(spindle shaped)
• White coloured
• 0.5-1 cm long
• Tail pointed
• Males smaller than females
and posterior body is curved
and sharply truncated(found
only after purgation)
Stool examination by Dr. Priyanka
Buragohain
111
112. • EGGS
• Colourless(not bile
stained)
• 20×50 µm
• Assymetrical, Oval
planoconvex,
• thin transparent
shelled,
• contain coiled tadpole
likelarva inside
• Floats in saturated salt
solution
Stool examination by Dr. Priyanka
Buragohain
112
113. Ancylostoma duodenale
• Hook worm
• Small greyish white or pink
coloured cylindrical
• 1-1.5 cm long
• One end is curved like a hook
• 6 teeth, 4 hook like on ventral
surface and 2 knob like on the
dorsal surface
Stool examination by Dr. Priyanka
Buragohain
113
114. EGGS
• Oval or elliptical in shape
• 40x60 µm sized egg
• Colourless(not bile
stained)
• Surrounded by a
transparent hyaline
shelled membrane
• Contains 4 segmented
ovum inside.
• Floats on saturated
solution of salt
Stool examination by Dr. Priyanka
Buragohain
114
115. Trichuris trichiura
• Whip worm
• Looks like a tiny whip
with a handle and a lash
• 3-5 cm in length
• White coloured
Stool examination by Dr. Priyanka
Buragohain
115
116. • 25x50 µm sized egg
• Brown coloured
• Double shelled, outer
one is bile stained
• Thick shelled, barrel
shaped with mucus plug
at both pole
• Single ovum
• floats in saturated
solution of common salt
Stool examination by Dr. Priyanka
Buragohain
116
117. Strongyloids stercoralis
• Adult worm:
• Females are readily
discovered than males
• 2.5mm ×40-50 µm
(females)
• Posterior extrimity is
pointed
• Males are shorter and
broader than females
Stool examination by Dr. Priyanka
Buragohain
117
118. Stool examination by Dr. Priyanka
Buragohain
118
• Eggs
• Eggs are conspicuous within the body in a
single line
• 55-30µm
• Thin shelled
• Transparent, oval
• Contain larva ready to hatch. It is the larva not
the eggs are found in stool.
119. • Rhabditiform larvae
• Develop directly from
gravid females
• Short mouth, double-
bulb oesophagus
• Filariform larvae
• Longer and slender
• Short mouth and
cylindrical oesophagus
Stool examination by Dr. Priyanka
Buragohain
119
121. Helminthes that float/do not float on
saturated solution of saline
Stool examination by Dr. Priyanka
Buragohain
121
• A. Duodenale
• N. Americanas
• E. Vermicularis
• H. Nana
• A. Lumbricoids
• T
. Trichuria
• H. Diminuta
Eggs that float Eggs that do not float
• A. Lumbricoids
• T
. solium
• T
. Saginata
• Trematodes
• F. Buski
• F. Hepatica
• C. Sinensis
125. Plant hairs can be confused for larvae
oh hookworm or Strongyloides stercoralis
Plant hair resembling S. strongiloids
Stool examination by Dr. Priyanka
Buragohain
125
126. Parasite of earth worm
Pollen grain resemblening to
fertile egg of A. lumbricoids
Stool examination by Dr. Priyanka
Buragohain
126
Bee pollen resembling t. Trichuria egg
128. STOOL CULTURE
• Used to detect the presence of disease
causing(pathogenic )bacteria
• Help to diagnose an infection of digestive
system
• Used in conjunction with stool test
• Reference range for stool culture is negative
Stool examination by Dr. Priyanka
Buragohain
128
129. Most common bacteria for culture of stool
• Campylobacter species
• Salmonella species
• Shigella species
• Yersinia species
• Vibrio species(travel history)
• Some bacteria cause illness by producing
toxins(PCR, Antigen test are to be done with stool
test)
• Escherichia coli
• Clostridium difficile
Stool examination by Dr. Priyanka
Buragohain
129
130. Collection
• Specimen collected via rectal swab(in infants)
• Sterile collection container not required
• No detergent or preservative should be present in
the container
• Specimen should be immediately transported to
the laboratory
• If transport is delayed by longer than 2 hours,
transport media(eg Cary- Blair) is recommended
• Samples must be sent in a sealed, leak-proof
container marked with a biohazard sticker
Stool examination by Dr. Priyanka
Buragohain
130
131. Medias used commonly
• MacConkey agar- Salmonella species, shigella
species
• Eosin methylene blue agar
• Triple sugar iron(TSI)- differentiate salmonella
and shigella
• Sabouraud agar
• Hekteon enteric agar
• Selenite broth
Stool examination by Dr. Priyanka
Buragohain
131
132. Summary
Stool examination by Dr. Priyanka
Buragohain
132
• Definition of stool
• Composition of stool
• Precaution and collection of
sample
• Physical examination
• Chemical examination
• Microscopic examination
• Artifacts
• Stool culture
