The document provides information on urine and stool examination procedures. Urine analysis includes physical, microscopic, and chemical tests to evaluate health and diagnose kidney, urinary tract, and other diseases. Stool examination includes physical, microscopic, and chemical analysis to diagnose gastrointestinal conditions like diarrhea and detect parasites. Both exams provide valuable information for disease diagnosis and monitoring patient health.

1. URINE & STOOL
EXAMINATION

2. URINE EXAMINATION
Urine analysis (Urinalysis) is one of the oldest
laboratory procedures in the practice of medicine.
It is done for general evaluation of health,
diagnosis of disease of the kidneys or urinary tract,
diagnosis of other systemic disease that affect
kidney function, monitoring of patients with
diabetes, and screening for drug abuse.
Sample Collection:
• Mid-stream urine collection

3. Physical Examination of Urine
• Volume: In normal adults, daily urine collection is
about 600-2,000 mL. In infants, it is 300-600
mL/day. Volume of urine is measured by
collecting 24 hour urine samples.
• Color and Appearance: Normal urine is pale and
transparent. Urine can turn turbid due to
presence of any solid content like cells, casts,
crystals, solutes, bacteria etc.

4. Color variation of urine

5. Physical Examination of Urine
Odor: Normally urine has a faint aromatic odor. Urine may emit different
smells depending upon its biochemical constituent:
• Fruity: Ketoacidosis
• Ammonical: Old sample, bacterial decomposition
• Putrid (like fecal): UTI
pH Reaction: Reflects ability of kidney to maintain normal hydrogen ion
concentration in plasma and ECF. Urine is normally acidic with pH
varying from 5.5-6.8.
Urine pH is measured using:
• pH indicator paper strips
• pH meter

6. Physical Examination of Urine
Specific Gravity (SG):
•Measures the concentrating and diluting power of
kidney. Concentrating ability of kidney is one of the
first function to be lost as a result of damage due to
renal tubules.
•Normal SG is 1.008-1.030 in a 24-hour sample.
Methods of measuring:
•Urinometer
•Refractometer
•Dipstick method

7. Physical Examination of Urine
•SG is increased in dehydration, restricted fluid intake,
diarrhea, vomiting, fever, excessive sweating in
summer, diabetes mellitus.
•SG is decreased in excess fluid intake, chronic kidney
disease, bilateral polycystic kidney, chronic
pyelonephritis, and hypertension.

8. Microscopic Examination of Urine
A variety of normal and abnormal cellular
elements may be seen in urine sediment:
•Red blood cells (RBCs): RBCs in urine appear
as refractile disks. Presence of RBCs in urine is
called hematuria. RBCs appear in urine in
urinary infections, tumors and calculi, hemolytic
anemia, patients on oral anticoagulant.
•White blood cells: Also called pus cells. Pus cells
more than 5/hpf are seen in acute urinary tract
infection.

9. Microscopic Examination of Urine
•Epithelial cells: Arise from any site in genitourinary tract,
from kidney to the urethra or from the vagina. Normally a
few cells are found. Increased number of cells are found
in urinary tract infection, elderly female, prolapsed
uterus.
•Urine casts: Urinary casts are cylindrical aggregations of
particles that form in the kidney, dislodge, and pass into
the urine. In urinalysis they indicate kidney disease.
•Crystals: It may be present in the urine sediment. Many of
crystal found in urine have little clinical significance
except in case of metabolic disorders. Crystals are
identified by their appearance and their solubility
characteristics.

10. Microscopic Examination of Urine
• Bacteria: Normal urine contains no bacteria. However, bacteria
often grow in normal urine if it is left in warm room. In fresh
urine means that the patient has a urinary infection.
• Yeast and Fungi: Budding yeasts are common in patients of
diabetes mellitus.
• Spermatozoa: They are often found in the man's urine and are
quite normal. After sexual intercourse they may be found in a
woman's urine.
• Parasites: One of the commonest parasites are the ova of a
worm called Schistosoma haematobium, which lives in the veins
of the walls of bladder and ureters.

11. Chemical Analysis of Urine
• Normal range of urine protein is less than 150 mg/in 24
hour urine sample. Increased excretion of protein in urine is
proteinuria.
• Tests:
• Heat coagulation test
• Heller's nitric acid test may
• Sulfosalicylic acid test
• Esbach's albuminometer test
• Urine protein electrophoresis

12. Chemical Analysis of Urine
Heat Coagulation Test:
• It is a cheap test which does not require technical expertise.
• Principle: Proteins are coagulated on heating.
• Procedure: Fill 3/4th of the test tube with urine.
• Heat upper part of this tube.
• Coagulation can be formed due to proteins, phosphates, or
urates.
• Add 3 to 4 drops of 3% Acetic acid.
• If the coagulum persists, then it is due to proteins and if it
disappears it is due to phosphates.

13. Chemical Analysis of Urine
•Interpretation of the heat coagulation test:
•No cloudiness-absence of proteins
•Haziness-traces of proteins present (up to 10 mg/
dL)
•Cloudiness (1+)-10-50 mg/dL
•Moderate cloudiness (granular) (2+)-50-200 mg/dL
•Marked cloudiness (Flocculations) (3+) 200 - 500
mg/dL
•Thick cloudy precipitate (4+) - More than 500 mg/ dL.

14. Chemical Analysis of Urine
• Sugar:
• Presence of sugar in urine is known as glucosuria. Most of the time it
occurs as part of a systemic disease process.
• Urine tests for sugar:
• Benedict's test
• Fehling's test
• Benedict's Test (Semi-Quantitative): It is a simple test for reducing
sugars, which includes all monosaccharides (e.g., glucose, fructose,
galactose) and many disaccharides, including lactose and maltose.
• Principle of Benedict's Test:
• Reducing sugars under alkaline condition can reduce cupric ions
(Cu2+) present in Benedict's solution, to cuprous form (Cu), which is
responsible for the change in color of the reaction mixture.

15. Chemical Analysis of Urine
•Procedure of Benedict's Test:
•Pipette 5 mL of Benedict's reagent in a test tube.
•Add 8 drops of urine to the Benedict's reagent.
•Heat carefully on a flame of a gas burner.
•Cool and observe the color change and precipitate
formation and analyze the test result.

16. Interpretation of results of Benedict's Test

17. Chemical Analysis of Urine
• Ketones (Ketonuria): Presence of ketone bodies which are intermediate
products of fat metabolism, in urine is considered abnormal.
• Rothera's Test:
• Principle: Acetone and acetoacetic acid develops purple colored complex
with sodium nitroprusside in alkaline medium.
• Procedure:
• Take 5 mL of urine in a test tube and saturate it with ammonium sulfate.
• Add 1 crystal of sodium nitroprusside.
• Mix. Run liquid ammonia carefully at the side of the tube so as to form a
layer on top of the saturated urine.
• Formation of purple ring at junction of two fluids indicates positive test.

18. Chemical Analysis of Urine
•Occult Blood: Presence of blood in urine is an
abnormal finding and is called hematuria.
•Benzidine Test:
•Add 2 mL of urine in test tube.
•Add 2 mL of 1% Benzidine solution in acetic acid.
Shake well.
•Add 2 mL of hydrogen peroxide.
•Mix and observe for a change in color.
•Positive result: Green or blue color indicates
hematuria.

19. Chemical Analysis of Urine
•Bile Salts: Bile salts are not present normally in urine.
•Hay Sulfur Test: The principle of the test is, bile salts
when present, decreases surface tension of urine.
When dry sulfur powder is sprinkled on the surface of
the urine they sink to the bottom if bile salts are
present.
•Bile salts are excreted in hepatocellular and
obstructive jaundice.

20. Chemical Analysis of Urine
•Bilirubin:
•Bilirubin is not found in urine normally.
•Fouchet's Test:
•The reagent contains oxidizing agents
(Trichloroacetic Sample acid and 10% Ferric chloride
solution), which oxidizes yellow bilirubin to green
biliverdin.
•Result: A green color indicates the presence of
bilirubin.
•Bilirubin is excreted in hepatocellular and obstructive
jaundice.

21. Chemical Analysis of Urine
•Urobilinogen:
•Ehrlich's Test:
•Urobilinogen reagent (P-
dimethylaminobenzaldehyde) produces
pink color normally.
•Result: Dark red color--Positive for
urobilinogen.

22. Urine Dipstick Test for Various Parameters
•The presence of normal and abnormal
chemical elements in the urine is detected
using dry reagent strips called dipsticks. The
strips are impregnated with reagents. The
reagents are activated and a chemical
reaction occurs. The
chemical reaction results in a specific color
change. These color changes are compared
with available color code on container.

23. Microbiological Examination
• Urine Culture and Sensitivity:
• Urinary tract infection (UTI) is one of the most commonly
diagnosed infections in both outpatient and inpatient populations.
In order to make an accurate diagnosis urine culture is done.
• Sample Type:
• Midstream and clean catch morning urine sample is used
commonly.
• Suprapubic aspirate (SPA) is seen as the "gold standard",
especially in infants.
• Catheter urines: samples taken from an indwelling catheter.
• Methods: It is done by two methods-Manual culture and
automated culture.

24. Microbiological Examination
• Procedure:
• Mix the urine sample.
• With the help of platinum loop streak on culture media.
• Usually standard nutrient agar, glucose topped and
standard MacConkey and CLED (cysteine-, lactose, and
electrolyte-deficient) agar are used.
• Incubate at 37°C aerobically for 24-48 hours.
• On the following day count the number of colonies.
Colony count no. >100,000/mL indicates infection:
• Most common causative bacteria are Escherichia coli,
Klebsiella pneumoniae, streptococci, Enterobacter etc.

25. Microbiological Examination
•Urine Pregnancy Test (UPT):
•This is a rapid and easy pregnancy testing method.
Commercial UPT kits are available, which detect B-
hCG excreted in the urine of pregnant females.
•Principle:
•The device contains a unique set of dye-conjugated
and immobilized antibodies used to produce a
distinctive visual pattern, indicating elevated
concentration of ẞ-hCG (≥25 mIU/mL) in the test
sample and a positive pregnancy test.

26. STOOL EXAMINATION
•Human feces is called as stool. It is the
waste residue of indigestible materials
expelled through the anus during defecation.
•Stool examination is done in cases of
diarrhea, dysentery, malabsorption
syndromes, and colorectal malignancies.

27. STOOL EXAMINATION
• Sample Collection:
• Stool should be collected in a dry, sterilized, wide mouthed glass, or
plastic container.
• Avoid contamination with disinfectants in bed pan, urine, any other
body secretions or water.
• Tightly screw the container. Name and label immediately.
• Examination of stool should be done within 1 hour of sample
collection. So transport the sample immediately to laboratory.
• Avoid heat exposure.
• If the sample delivery is delayed, then use stool preservatives.
• 5%-10% formalin
• Polyvinyl alcohol
• Three random samples should be tested before giving negative test
results.

28. Physical Examination of Stool
•Quantity: Adequate sample 2-3 gm in
weight or 4-5 mL in volume.
•Color and appearance:
•Normal: Light to dark brown, soft, well
formed.

29. Abnormal color & Appearance of stool

30. Physical Examination of Stool
•Abnormal consistency:
•Watery, thin stool mixed with mucous and
blood is suggestive of Typhoid and
Amoebiasis.
•Liquid stool mixed with mucous and pus is
suggestive of Ulcerative Colitis, Regional
Enteritis. Shigella, Salmonella infection,
Acute diverticulitis and Intestinal TB.

31. Physical Examination of Stool
•Rice water stool which is colorless and without
odor is suggestive of Cholera.
•Odor: Foul odor due to bacterial degradation of
tryptophan in intestinal content. A sickly sweet
odor in undigested lactose (intolerance).
•pH:
•Normal: 6.9-7.2
•Alkaline: Protein indigestion
•Acidic: Excess carbohydrates

32. Microscopic Examination of Stool
• It is done on wet-mount slides, and less often on stained
smears.
• Methods of wet-mount slide preparations.
• Direct Mount Slide Procedure:
• Apply the patient's sample to a small area on a clean
microscope slide. Remove any gross fibers and particles.
• Immediately before the specimen dries, add 1 or 2 drops of
normal saline with a pipette. Mix with pipette tip.
• Lugol's iodine and Eosin 1% is used in a similar way to
prepare the slides. Iodine stain helps to examine the nuclei
of cysts, eosin helps to see motile organisms.

33. Microscopic Examination of Stool
• Concentration Method to Detect Parasites:
• This increases the ability to detect cysts/ova of the parasite
even when they are present in small amount.
• Hypersaturated salt solution: About 10 gm of stool is mixed
with concentrated salt solution in a test tube and filled to
the brim. A cover slip is placed on the top. Wait for 30
minutes. Parasitic ova stick to the cover eye slip. Examine
it under the microscope.
• Sedimentation technique using formal ether or zinc sulfate.
This is based on specific gravity. After centrifugation, the
stool's parasites are heavier and settle down at the bottom
as sediments.

34. Microscopic Examination of Stool
•Parasites, Ova and Cysts: Stool is commonly infested
by parasites by consumption of contaminated water,
food or soil. Different types of parasites, their ova or
cyst are identified in stool sample by their morphology
on naked eye examination, wet smear or stained
smear study under of the microscope

35. Chemical Examination of Stool
•Occult Blood Test:
•This is the most important screening test for intestinal
cancers. It may also be positive in parasitic
infestations like hookworm, E. histolytica etc.
•Method- Benzidene test. Place small quantity of stool
specimen on a clean glass slide, add 1 or 2 drops of
benzidene solution. Observe change in color.
•Observations: Color changes to Green to Blue: Occult
blood present.

36. Chemical Examination of Stool
•Urobilinogen:
•Ehrlich's aldehyde test is used to detect increased
fecal excretion of urobilinogen which is seen in
hemolytic anemia. Urobilinogen is decreased in biliary
tract obstruction, severe liver disease, oral antibiotic
therapy.
•Test for Reducing Sugars:
•Detection of reducing substances (sugars) in stool is
done to diagnose certain malabsorption syndromes
which may result in diarrhea.

37. Chemical Examination of Stool
•Benedict's test for reducing sugars is used to test
freshly collected stool sample for lactose. Deficiency
of intestinal enzyme lactase causes increased stool
sugar levels, and is a common cause of
malabsorption.
•Fat:
•Normally less than 7 gm/24 hours fat is excreted
during 3 days period. Fat is detected by addition of a
drop of Sudan-III to a wet preparation which gives a
red color.

38. Chemical Examination of Stool
•Stercobilinogen:
•It is formed from urobilinogen by bacteria in the
intestine. It gives feces its brown color. Average
excretion is 150 mg/ day. Increased excretion is seen
in jaundice.
•Nitrogen:
•Content depends upon the nature of the diet. The
normal amount is 1-1.5 g/day.

39. Microbiological Examination of Stool
• Stool Culture:
• Human feces contain more than thousand organisms per
gram wet weight as normal flora. These include:
• Gram negative: Escherichia coli, Enterobacte Proteus, and
Pseudomonas aeruginosa.
• Gram positive: Clostridia, Lactobacilli & Enterococci.
While most of the normal bacteria are anaerobes, most of the
bacterial stool pathogens grow on aerobic culture plates.
Therefore, aerobic culture media are used for culture. Any
suspicious organisms that grow on the media are identified
using microscopic and biochemical tests.

40. Microbiological Examination of Stool
• Hanging Drop Test:
• Place a drop of stool in the center of a coverslip. Place a drop
of vaseline at each corner of the coverslip. Invert a slide and
examine microscopically for motile organisms like Vibrio
cholerae.