Muhammad Naveed

Medical Lab Technologist

M.Phil Molecular Biology
and Biotechnology
 DEFINITION
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
• A dark greenish mass that accumulates in the
bowel during fetal life and is discharged
shortly after birth
• or in simple words
• newborn’s first feces.

• SCATOLOGY or CAPROLOGY is the study of

feces.
 COMPOSITION
• ¾ Water, ¼ Solid
• Undigested and Unabsorbed food
• Intestinal secretions, Mucous
• Bile pigments and Salts
• Bacteria and Inorganic material
• Epithelial cells, Leukocytes
 COLLECTION
• Universal Precautions
• Stool should be collected in a dry, sterilized,
wide mouthed container.
• It should be uncontaminated with Urine or any
other body secretions.
• Properly named and always a fresh sample
should be tested.
• Deliver immediately after collection
If there is delay, stool should be collect in 10
% formalin or PVA
• fixative, storage temperature is not
critical. Because of the cyclic life cycle of
parasites
• Do not collect stool from the toilet bowl. A
clean, dry bedpan is the best.
M A C R O S C O P I C E X A M I N AT I O N
• Volume <200gms/day
• Colour
• Consistency
• Odour
• Blood, Mucous
• Parts of parasite and Adult Parasite
 COLOUR OF STOOL
Human fecal matter is normally yellowish brown
in colour which results from a combination of
bile and bilirubin.
VARIATIONS
Bright Red/Maroon Tan/Clay
Blood streak White
Yellow Pale greasy
Green
Black
Blue
COLOUR OF FECES-in Infants
Exclusively breast fed infants pass loose and green
or pasty and yellow stools.
Infants fed on cows’ milk preparations pass stools
of a paler yellow colour and of a much firmer
consistency.
 CONTINUE
• Babies fed on newer modified cows’ milk
preparations have clay coloured or greenish
stools.
• Some healthy children may pass frequent,
loose stools containing undigested vegetable
matter called as Toddler’s diarrhoea.
 Toddler’s diarrhoea
• also known as chronic nonspecific diarrhea of
childhood, and it affects children from 6
months to 5 years of age. Children
with toddler's diarrhea will have 3-10 loose
stools per day. These stools typically occur
during the day when the child is awake and
sometimes immediately after eating.
CONSISTENCY OF STOOL
Separate hard lumps, like nuts (hard to pass).

Sausage-shaped but lumpy.

Like a sausage but with cracks on the surface.

Like a sausage or snake, smooth and soft.

Soft blobs with clear-cut edges.

Fluffy pieces with ragged edges.

Watery, no solid pieces. Entirely Liquid.

 ODOUR OF STOOL
Basically depends on the pH of the stool and
INDOLE and SKETOLE are the substances that
produce normal odour formed by Intestinal
bacterial fermentation and putrefaction.

A foul odour is caused by degradation of

undigested protein and excessive carbohydrate
intake.
Sickly (sickness) sweet odour is produced by
undigested Lactose.
• Diarrhoea mixed with mucous and Blood is
suggestive of Typhoid, Amoebiasis, Typhus,
Large bowel Carcinoma.
• Diarrhoea mixed with mucous and Pus is
suggestive of Ulcerative Collitis, Regional
Enteritis, Shigellosis, Salmonellosis, Acute
diverticullitis, Intestinal TB.
• Rice water stools which is colourless and almost
devoid of odour is suggestive of Cholera.
• Pasty stool with high fat content is suggestive of
Cystic fibrosis-butter stool.
• Translucent gelatinous mucous clinging to the
surface of the formed stool is found in Spastic
Constipation, Excessive straining, Mucous
collitis.
 PA R A S I T E
•Round worm
•Hook worm
•Tape worm
•Pin worm
•Whipworm
MICROSCOPIC
E X A M I N AT I O N
 M AT E R I A L S
• Microscope slides
• Cover slips
• Sodium chloride solution
• Lugol’s Iodine Solution
• Wooden applicator
• Fresh stool
• Gloves
 S L I D E P R E PA R AT I O N
Saline Specimen Prep.
SLIDES Iodine Specimen Prep.
 CONCENTRATION METHOD to detect
Ova.
• A drop of warm Saline or Lugol’s Iodine is
placed over a clean microscopic slide.
• About 2mg of stool sample should be taken
and mixed with stick placed over the slide.
• Coverslip is placed avoiding air bubbles.
• Examined under Microscope.
PIN WORM EGG COLLECTION
Eggs of Pin worm – Enterobius vermicularis rarely
appear in stools. These are usually collected in
the folds of skin in perianal region.

COLLECTION
Cotton swab / Plaster patch – Anus especially in
early morning – Dipped in Saline – Observed.
E X A M I N AT I O N O F PA R A S I T E S
Warm stools are best for detecting Ova or
parasites. Do not refrigerate the specimen.
Because of life cycle of parasites, three separate
random stool specimens are recommended for
examination.
 N O R M A L VA L U E S
• Undigested food materials – None to small
amount
• Starch – None
• Eggs, Cysts, Parasitic fragments – None
• Yeasts – None
• Leukocytes – None
 L E U KO C Y T E S I N S T O O L
Large amounts of leukocytes is suggestive of
Chronic Ulceratice Collitis, Chronic Bacillary
Dysentry, Localised Abscess, Fistulas.
Mononuclear Leukocytes appear in Typhoid.
Polymorphonuclear Leukocytes appear in
Shigellosis, Salmonellosis, Invasice E. coli
diarrhoea, Ulceratice Collitis.
Absent Leukocytes in Cholera, Viral diarrhoea,
Amoebic Collitis, Giardiasis.
 HOOKWORM
Ancylostoma duodenale.
 ROUNDWORM
Ascaris lumbricoides

2,40,000 eggs per day

 TA P E W O R M
Taenia solium-Pork
Taenia saginata-Beef
 WHIPWORM
Trichuris trichura
 PINWORM
Enterobius vermicularis
 E N TA M O E B A
Entamoeba histolytica
E N TA M O E B A
 GIADIASIS
Giardia lamblia
 S T O O L C U LT U R E
Normal Microbial flora of GI tract contains
following organisms

Gram –ve - E. coli, Enterobacter, Proteus,

Pseudomonas aeruginosa, Bacteroides.
Gram +ve - Clostridia, Lactobacilli, Enterococci,
Anaerobic streptococci.
• Human feces contain approximately 1011
organisms per gram wet weight as normal
flora. Whereas gut bacterial pathogens rarely
exceed 105 organisms per gram.
 HANGING DROP TEST
•Place a drop stool in the centre
of a coverslip.
•Place a drop of wax, vaseline at
each corner of the coverslip.
•Invert a slide with a central
depression over the coverslip.
•The coverslip will stick to the
slide and when the slide is
inverted the drop of bacterial
culture will be suspended in the
central depression of the slide.
•Examine microscopically (X100)
for motile organisms.
 CHEMICAL
E X A M I N AT I O N
 NORMALCY
• Water – Upto 75%
• pH – 5.8 to 7.5
• Occult blood – Negative
• Sodium – 5.8 to 9.8 mEq/24hrs
• Chlorides – 2.5 to 3.9 mEq/24hrs
• Potassium – 15.7 to 20.7 mEq/24hrs
• Lipids / Fatty acids – 0 to 6 gms/24hrs
• Nitrogen - <2.5g/24hrs
 pH
Increased pH-ALKALINE Decreased pH-ACIDIC
• Colitis • Carbohydrate
• Antibiotic use Malabsorption
• Villous adenoma • Fat Malabsorption
• Excess Protein in diet. • Disaccharidase
defficiency
 O C C U LT B L O O D
PRINCIPLE – BENZIDINE TEST
Perioxidase action of hemoglobin in
blood converts hydrogen peroxide to water and
nascent oxygen. This oxygen oxidises benzidine
in acid medium to form green to blue coloured
complex
GUAIAC TEST
O C C U LT B L O O D c o n t …
Found in Ulcers,
Diverticullitis,
Ulcerative Collitis,
Diaphragmatic Hernia,
Adenoma,
CA Colon, Gastrium