CHAPTER 9
Stool Analysis
INTRODUCTION
The stool of a healthy adult on an ordinary mixed diet is well formed,
semisolid in consistency,reaction is alkaline or neutral, and brown
in color. The feces are normally, composed 25% of fecal matter
of
while rest of it is water.In certain the feces may contain such
diseases,
substances which are not normally present in healthy individual such
as blood, mucus, parasites,intestinal calculi, pus, and pathogenic
organisms (bacteria,fungi and viruses),etc.
The amountof adult stool is nearly 150 to 250 g/day. Stoolshould
be collected in a clean, dry covered container and should not be
mixed with urine.
The stool should be examined for macroscopic examination,
chemical examination, and microscopic examination.
MACROSOPIC EXAMINATION
Stool should be examined macroscopically for following points:
Color
Normal stoolis light, or dark brown in color.
Following abnormal colors are found:
Green--in infantile diarrhea.
Clay-in obstructive jaundice, excess of fat, tuberculous peritonitis.
Dark brouwn or bright red -bleeding from distal colon.
Streaks of brightred blood-piles, fissures, carcinoma of rectum.
Black-gastrointestinal bleeding, tuberculosis.
Stool
Analyis 135
Odor
after use of oral antibiotics,
foul smelling
Odorless in acute
enterítis,
rin rectum and distal colon.
malignantulcer
Mucus
Mucus is seen in bacillary dysentery.
Pus
Pus with blood and mucus present in ulcerative colitis, bacillary
enteritis.
dysentery, regional
Calculus
Gall stones may be seen in feces.
Blood
Impart a dark red to black color and a terry consistency.
Parasites
Segments of tapeworm and roundworm may be seen in respective
infections.
CHEMICAL EXAMINATION
Normally, pH of stoolis 6.8to 7.3 on mixed diet. Excess ofcarbohydrate
diet produces acidityand excess of proteins produce alkalinity.
MICROSCOPIC EXAMINATION
odine or 1odine preparation should be made and examined with the
low and high power
objectives.
Various ova or
cystsS may be seen(Fig. 9.1) asabnormal constituents
of stool. This includes
ovas of following parasites:
i.
Hookworm iv. Taenia
ii. Ascaris
(Roundworm) V. E. vermicularis
ii. Trichuristrichiura vi. H. nana
136 Clinical Pathology, Hematology and Biood Barhing
Other Abnormalities
1. Vegetablecells and fibers-incase of indigestion.
2. Starch granules--incarbohydrate dyspepsia.
3. Muscle and elastic fiber.
4. Fats and fatty acidsin fatty dyspepsia.
pus cells,
5. Cells-abnormal cells in stool includes-epíthelial,
RBCS.
macrophages, short cells, eosinophils,
Crystals
The abnormal crystals includes:
phosphate crystals, fatty acid
crystals.
a. Calcium oxalate, triple
conditions of intensive
is seen in ulcerative
b. Needle shaped crystals
etc.
dysentery, malignant ulcers,
S68
AMOBIC
TROPHOoT
BLASTOCrs
Fig. 9.1: Common things found in stool
Stool Analysis 137
various bacteria, protozoa, metazoa, yeast andfungi
Besides these,
mav also be seen in stoolexamination.
Concentration Methods for Ova and Cyst
Take about one gram of feces and thoroughly emulsify with super
sodium chloride solution in water in
a suitable
container.
saturated
should have diameter as well as depth i about oneof
The container
is so filled with the emulsion that a slide placed
inch. The container
this position for
on it just touches the preparation. The slideis kept in
about 25 minutes, and gently inverted. Ova of many
helminths will
Aoat and stick to the slide. A coverslip is placed
on the slide and the
Dreparation is examined under thelow power of microscope.
Occult Blood Test
Make a suspension offecesand boil fortwominutes to destroy,oxidize
and inactivate bacteria or enzymes. Cool and add2 mL of saturated
benzidine in glacialacetic acid, mix well and add lmi.
solution of
(30%)hydrogen peroxide. Orthotoldine or guaiac solution can be used
instead of benzidine solution.
A deep blue color indicates the presence of hemoglobin.
The presence of blood in the stool is of great significance in
diagnosing the diseaseofinflammatory, neoplasticor ulcerativeorigin
of gastrointestinal tract.
Iron may affect thetest, so patient should not take meat diet, green
vegetable, or iron in any form.
