full stool examination instruction

1. Practical parasitology
By
Abdulaziz Saleh Ba mahel

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stool Examination:
is a series of tests done on a stool (feces) sample to help
diagnose certain conditions affecting the digestive tract.
Introduction
Stool:
Waste residue of indigestible material (cellulose during
the previous 4 days).

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Introduction
1) Bile pigments and salts.
2) Intestinal secretions, including mucus.
3) Leukocytes that migrate from the bloodstream.
4) Bacteria and Inorganic material(10-20%) chiefly
calcium
and phosphates.
5) Undigested and unabsorbed food.
Composition:

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 Help identify diseases of the digestive tract, liver, and
pancreas.
 Help find the cause of symptoms affecting the digestive
tract, including prolonged diarrhea, bloody diarrhea, an
increased amount of gas, nausea, vomiting, loss of
appetite, bloating, abdominal pain and cramping, and
fever. Ulcer
 Look for intestinal parasites.
 Look for the cause of an infection, such as bacteria, a
fungus, or a virus.
Introduction
Clinical application:

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1) Polyvinyl alcohol (PVA):
 Preserving cysts, trophozoites, helminth eggs and Larvae.
 Useful for liquid specimens.
 Used in ratio of 3 parts of PVA to 1 part of fecal specimen.
 Permanent stained smear can be prepared from it.
 Stable for long periods of time (months or years) in sealed
containers Poisonous .
Introduction
Preservation of specimens

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2 ) Schaudinn’s:
 Used with fresh stool or material recovered from the
intestinal mucosal surface.
 Preserving trophozoites and cysts.
 Fecal smears ( at least 2 slides) prepared and
immediately immersing them in Schaudinn’s fixative.
Preservation of specimens
Introduction

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Preservation of specimens
Introduction
3) 10% Formalin:
 Protozoan cysts (not trophozoites), helminth eggs (hot
formalin, 60c) and larvae are preserved for long
periods of time.
4) Merthiolate iodine formalin (MIF):
 Used with all common types of stools and aspirates,
protozoa, eggs, and larvae.
 Unstable for long periods of time.

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Stool examination
 Stool sampling:
 Stool should be collected in clean – dry – wide neek container.
 Specimen should be exam within few hours of being collect.
 Never leave stool specimens exposed to the air in containers
without lids.
 Never accept stool specimens mixed with urine.
 Never examine stool specimens without first putting on gloves.
 Always examine stool specimens within 1–4 hours after collection.
 If several specimens are received at the same time, examine the
liquid stools and those.
 containing mucus or blood first, as they may contain motile
amoebae (which die quickly).

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Stool examination
Macroscopic ex. Microscopic ex. Other Ex.
• Color
• Order
• Consistency
• Mucous
• Blood
• Ph.
• Naked eye parasite
• Direct saline smear
• Iodine smear
• Concentration
technique
• Stool culture
• stool for Occult
blood
• Stool h. pylori

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Macroscopic examination
• Color
• Order
• Consistency
• Mucous
• Blood
• Ph.
• Naked eye parasite

11.  Normal:
Brown color is the normal color of stool
Why stool color is brown? The characteristic brown color of feces is due to stercobilin and
urobinin,
 Abnormal:
• Yellow to yellow-green : Severe diarrhea.
• Black color: indicate iron medication (for treatment of anemia) or upper GIT bleeding
(due to peptic ulcer, stomach carcinoma or esophageal varices).
• Bright red color: indicate lower GIT bleeding (due to piles and anal fissure).
• Clay color (gray-white): indicate obstructive jaundice
• Red brown color: indicate drugs as Tetracyclines, and Rifambicin antibiotics
• Green color: indicate medications as Diathiazine, Mercurous chloride also vitamins
cause green color of stool
color

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 Normal:
formed
 Abnormal:
Abnormal consistency may be graded as follow:
hard: seen in cases of constipation
Semi formed: seen in the cases of parasitic infection
Soft: seen in the cases of parasitic infection
Watery: mostly seen in cases of bacterial infection
Consistency

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Consistency

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 Normal:
Normally undetectable or small amount produce by GIT and found
in the stool.
 Abnormal:
Abnormal mucus in the sample appears as white patches
and usually present with appearance pus and indicate
bacterial infection.
mucus with fresh blood in stool usually indicate amoebic
dysentery
Mucus

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 Normal:
Normally no blood seen in the stool
 Abnormal:
Abnormal fresh blood seen in cases
of lower GIT bleeding caused by:
•Bilharzias (schistosoma mansoni infection)
•anal fissure
•piles
naked eye blood

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Normal: no parasites or larva appear in the stool
Abnormal:
In some cases the whole worm or parts of its body appear in the
stool and can be seen by naked eye.
Naked eye parasite

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Normal:
Normally variable
Why stool pH is variable?
Because stool pH mainly depends on the type of diet
pH ( reaction)

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Odour
Normal:
Normally offensive
Why stool odour is offensive? Fecal odor results from gases produced by
bacterial metabolism, including skatole, mercaptans, and hydrogen sulfide.
Abnormal:
Odorless: usually seen if there is no fecal matter as in bacterial infection.
Very offensive: usually seen in cases of constipation and with certain
types of food that produce excessive gases.

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Microscopic examination
• Direct smear (WET MOUNT )
• Concentration technique

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Iodine wet mount
Saline Wet mount
Useful to stain of glycogen and
nuclei in cyst
Used to initiate microscopic
examination of stool its
employed to demonstrated of
egg, larva and protozoa cyst,
trophozoite.
Direct smear (WET MOUNT)

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Direct smear (WET MOUNT)
Materials used in stool examination
 microscope
 microscopic slides
 cover slides
 saline solution
 iodine solution
 marker
 Stick loop
 Dropping bottle

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Advantages
 It is a fast, simple, procedure
 provides a quick answer when positive
 to detect motile trophozoites;
 to detect ova and cysts present in moderate numbers;
 to detect erythrocytes, cellular debris or excess fat.
Direct smear (WET MOUNT)
Disadvantages
Not sensitive for detection of small number of parasite that is present in sample

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Direct smear (WET MOUNT)
procedure
 Take a dry microscope slide.
 Place drop of normal saline on one end of slide and drop of iodine to other end
 Using an wire loop, take a small portion (about 2–3mm diameter) of the stool.
a) If the stools are formed, take the portion from the centre of the sample and
from the surface to look for parasite eggs.
(b) If the stools contain mucus or are liquid, take the portion from the mucus
on the surface or from the surface of the liquid to look for amoebae.
 Mix the sample with the drop of normal saline solution on the slide.
 Cover it with cover slide exam using 10 X objective to seen motile parasite and 40 X
objective to seen parasite.

24. Drop saline and drop
iodine Part of stool mixed with saline and
iodine
Covered with Cover
slides
Show under
microscope

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Under microscope
1) Parasite: protozoa
-cyst
- Trophozoit
2) parasite metazoan
- egg
- Larva
-Adult worm
As you studying in theory part of
parasitology

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Under microscope
3) RBC
Normal:
Normally few amounts of RBCs (0-3) are seen.
Counting:
RBCs are counted under HPF of microscope and the range of count is
written for example 10-12 or 30-40 and so on.
Interpretation:
Abnormal RBCs under microscope is seen in:
•Bilharzias (schistosoma mansoni infection)
•anal fissure
•piles
•Entameba histolytica infection

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4) PUC cells
Normal:
Normally few amounts of pus (0-5) are seen
Counting:
Pus is counted under HPF of microscope and the
range of count is written for example 10-12 or 30-40 and so on.
if pus count is over 100 stool culture is recommended.
Interpretation:
Abnormal pus under microscope is seen in:
•Bacterial infection as Shigellosis , Salmonellosis
•Inflammation of the intestines, such as Ulcerative colitis
Under microscope

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Normal:
Normally found in the stool and graded as (1+)
Interpretation:
Increased starch in stool (++ or +++) indicate a
case of indigestion.
Under microscope
5) Starch

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Normal:
Normally found in the stool and graded as (1+)
Interpretation:
Increased fat in stool may indicate:
Pancreatic insufficiency as in pancreatitis due to reduced
pancreatic juice secretion.
Disorders affect the absorption of fats as sprue (celiac disease)
and infection with Giardia.
Fat
Under microscope
6) Fat

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Under microscope
Normal:
Normally found in the stool and graded as (1 +)
Interpretation:
Increased muscle fibers in stool have no clinical
significance and considered as residual food.
the presence of large amount of undigested meat
fibers in the stool may be caused by pancreatitis.
Note
7)muscle fibers

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8) Normal constituents of stool:
Bacteria:
normally non pathogenic bacteria are found in the stool and usually bacilli such as Escherichia
coli and Lactobacillus sp.
pathogenic bacteria may be found in stool ( such as Salmonella, Shigella, and Staphylococcus
aureus) and this will leads to pus formation, stool culture can differentiate between pathogenic and
non pathogenic bacteria.
Yeast: normally stool contain harmless yeast cells such as blastocystis hominis
Crystals: normally stool contain triple phosphate, calcium oxalate and
cholesterol crystal due to food ingestion.
Fibers: normally stool contains many fibers that may arise
from clothes or undigested plant food.
Air bubbles: normally found and has no clinical significance.
Oil droplets: normally found, they are very bright and completely rounded de
Under microscope

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Plant cells
Air bubble
Plant hairs
Plant fibre
Pollen grains
Non-human
coccidial oocysts Fat droplets
Soapy plaques
Starch cell Charcot leyden crystals Muscle fibers
Fatty acids Macrophage
Epithelial cells

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Report of stool examination

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Thank You