Urine analysis provides important information about kidney and overall health. A urine sample can be analyzed through macroscopic, chemical, and microscopic examination. The macroscopic exam evaluates attributes like color, clarity, and specific gravity. Chemical tests detect substances like proteins, glucose, ketones, and blood. Microscopic analysis identifies casts, crystals, epithelial cells, and other elements in urine sediment. Urine dipsticks provide a convenient, first-line screening for various analytes through color-changing indicators. Collectively, a urine analysis can detect disorders of the kidneys, urinary tract, and other body systems.
2. Introduction
Urine is formed in the kidneys, is a product
of ultrafiltration of plasma by the renal
glomeruli.
3. Collection of urine
Early morning sample-qualitative
Random sample- routine
24hrs sample- quantitative
Midstream sample-UTI
Post prandial sample-D.M
4. 24 hour urine sample
1. For quantitative estimation of proteins
2. For estimation of vanillyl mandelic acid,
5-hydroxyindole acetic acid,
metanephrines
3. For detection of AFB in urine
4. For detection of microalbuminuria
8. Urinary volume
Normal = 600-1550ml
Polyuria- >2000ml
Oliguria-<400ml
Anuria-complete cessation of urine(<200ml)
Nocturia-excretion of urine by a adult of >500ml
with a specific gravity of <1.018 at night
(characteristic of chronic glomerulonephritis)
12. Urinary pH/ reaction
Reaction reflects ability of kidney to
maintain normal hydrogen ion
concentration in plasma & ECF
Normal= 4.6-8
Tested by- 1.litmus paper
2. pH paper
3. dipsticks
15. Odour
Normal= aromatic due to the volatile fatty
acids
Ammonical – bacterial action
Fruity- ketonuria
16. Specific gravity
Depends on the concentration of various
solutes in the urine.
Measured by-urinometer
- refractometer
- dipsticks
17. Urinometer
Take 2/3 of urinometer container with urine
Allow the urinometer to float into the urine
Read the graduation at the lowest level of
urinary meniscus
Correction of temperature & albumin is a
must.
Urinometer is calibrated at 15or 200
c
So for every 3o
c increase/decrease add/subtract
0.001
For 1gm/dl of albumin add0.001
20. Low specific
gravity(hyposthenuria)
All causes of polyuria except gycosuria
Fixed specific gravity (isosthenuria)=1.010
Seen in chronic renal disease when kidney
has lost the ability to concentrate or dilute
22. Tests for proteins
Test – HEAT & ACETIC ACID TEST
Principle-proteins are denatured & coagulated
on heating to give white cloud precipitate.
Method-take 2/3 of test tube with urine, heat only
the upper part keeping lower part as control.
Presence of phosphates, carbonates, proteins
gives a white cloud formation. Add acetic acid 1-
2 drops, if the cloud persists it indicates it is
protein(acetic acid dissolves the
carbonates/phosphates)
23. Other tests
Sulphosalicylic acid test
Dipsticks
Esbach’s albuminometer- for quantitative
estimation of proteins
26. microalbuminuria
The level of albumin protein produced by
microalbuminuria cannot be detected by
urine dipstick methods. In a properly
functioning body, albumin is not normally
present in urine because it is retained in
the bloodstream by the kidneys.
Microalbuminuria is diagnosed either from
a 24-hour urine collection
27. Significance of microalbuminuria
an indicator of subclinical cardiovascular
disease
an important prognostic marker for kidney
disease
in diabetes mellitus
in hypertension
increasing microalbuminuria during the first 48
hours after admission to an intensive care unit
predicts elevated risk for acute respiratory failure
, multiple organ failure , and overall mortality
28. Bence Jones proteins
These are light chain globulins seen in multiple
myeloma, macroglobulimias, lymphoma.
Test- Thermal method(waterbath):
Proteins has unusual property of
precipitating at 400
-600
c & then dissolving
when the urine is brought to boiling(1000
c) &
reappears when the urine is cooled.
29. Test for sugar Test-BENEDICT’S TEST(semiquantitative)
Principle-benedict’s reagent contains
cuso4.In the presence of reducing sugars
cupric ions are converted to cuprous oxide
which is hastened by heating, to give the
color.
Method- take 5ml of benedict’s reagent in a
test tube, add 8drops of urine. Boil the
mixture.
Blue-green= negative
Yellow-green=+(<0.5%)
Greenish yellow=++(0.5-1%)
Yellow=+++(1-2%)
Brick red=++++(>2%)
30. Benedict’s test
Detects all reducing substances like
glucose, fructose, & other reducing
sustances.
To confirm it is glucose, dipsticks can be
used (glucose oxidase)
31. Causes of glycosuria
Glycosuria with hyperglycaemia-
diabetes,acromegaly, cushing’s disease,
hyperthyroidism, drugs like corticosteroids.
Glycosuria without hyperglycaemia-
renal tubular dysfunction
32. Ketone bodies
3 types
Acetone
Acetoacetic acid
β-hydroxy butyric acid
They are products of fat metabolism
33. Rothera’s test
Principle-acetone & acetoacetic acid react
with sodium nitroprusside in the presence
of alkali to produce purple colour.
Method- take 5ml of urine in a test tube &
saturate it with ammonium sulphate. Then
add one crystal of sodium nitroprusside.
Then gently add 0.5ml of liquor ammonia
along the sides of the test tube.
Change in colour indicates + test
34. Causes of ketonuria
Diabetes
Non-diabetic causes- high fever,
starvation, severe vomiting/diarrhoea
36. Urobilinogen
Test- ehrlich test
Causes-hemolytic anemia's
Bile salts-
Hay’s test
Cause- obstruction to bile flow (obstructive
jaundice)
37. Blood in urine
Test- BENZIDINE TEST
Principle-The peroxidase activity of hemoglobin
decomposes hydrogen peroxide releasing
nascent oxygen which in turn oxidizes benzidine
to give blue color.
Method- mix 2ml of benzidine solution with 2ml
of hydrogen peroxide in a test tube. Take 2ml of
urine & add 2ml of above mixture. A blue color
indicates + reaction.
38. Causes of hematuria
Pre renal- bleeding diathesis,
hemoglobinopathies, malignant
hypertension.
Renal- trauma, calculi, acute & chronic
glomerulonephritis, renal TB, renal
tumors
Post renal – severe UTI, calculi,
trauma, tumors of urinary tract
39. Type Plasma color Urine color
Hematuria normal Smoky red
m/s-plenty of
RBC’s
hemoglobunuria Pink,hepatoglob
in reduced
Red ,
occasional
RBC’s
Myoglobunuria Pink, normal
hepatoglobin
Red, occasional
RBC’s
40. Microscopic examination
Microscopic urinalysis is done simply pouring the
urine sample into a test tube and centrifuging it
(spinning it down in a machine) for a few
minutes. The top liquid part (the supernatant) is
discarded. The solid part left in the bottom of the
test tube (the urine sediment) is mixed with the
remaining drop of urine in the test tube and one
drop is analyzed under a microscope
41. Contents of normal urine m/s
Contains few epithelial cells, occasional
RBC’s, few crystals.
44. casts
Urinary casts are cylindrical aggregations
of particles that form in the distal nephron,
dislodge, and pass into the urine. In
urinalysis they indicate kidney disease.
They form via precipitation of
Tamm-Horsfall mucoprotein which is
secreted by renal tubule cells.
46. Hyaline casts
The most common type of cast, hyaline
casts are solidified
Tamm-Horsfall mucoprotein secreted from
the tubular epithelial cells
Seen in fever, strenuous exercise,
damage to the glomerular capillary
47.
48. Granular casts
Granular casts can result either from the
breakdown of cellular casts or the
inclusion of aggregates of plasma proteins
(e.g., albumin) or immunoglobulin light
chains
indicative of chronic renal disease
49.
50. Waxy casts
waxy casts suggest severe,
longstanding kidney disease such as
renal failure(end stage renal disease).
53. Fatty casts
Formed by the breakdown of lipid-rich
epithelial cells, these are hyaline casts
with fat globule inclusions
They can be present in various disorders,
including
nephrotic syndrome,
diabetic or lupus nephropathy,
Acute tubular necrosis
55. Pigment casts
Formed by the adhesion of metabolic
breakdown products or drug pigments
Pigments include those produced
endogenously, such as
hemoglobin in hemolytic anemia,
myoglobin in rhabdomyolysis, and
bilirubin in liver disease.
56. Crystal casts
Though crystallized urinary solutes, such
as oxalates, urates, or sulfonamides, may
become enmeshed within a hyaline cast
during its formation.
The clinical significance of this occurrence
is not felt to be great.
57. Red cell casts
The presence of red blood cells within the
cast is always pathologic, and is strongly
indicative of glomerular damage.
They are usually associated with
nephritic syndromes.
63. Epithelial casts
This cast is formed by inclusion or
adhesion of desquamated epithelial cells
of the tubule lining.
These can be seen in
acute tubular necrosis and
toxic ingestion, such as from mercury,
diethylene glycol, or salicylate.
64. Urine dipsticks
Urine dipstick is a narrow plastic strip which
has several squares of different colors
attached to it. Each small square represents
a component of the test used to interpret
urinalysis. The entire strip is dipped in the
urine sample and color changes in each
square are noted. The color change takes
place after several seconds to a few minutes
from dipping the strip. If read too early or
too long after the strip is dipped, the results
may not be accurate.
66. The squares on the dipstick represent the
following components in the urine:
∀ specific gravity (concentration of urine),
∀ acidity of the urine (pH),
∀ protein in the urine (mainly albumin),
∀ glucose (sugar),
∀ ketones
∀ blood
∀ bilirubin and
urobilinogen
67. The main advantage of dipsticks is that
they are
1. convenient,
2. easy to interpret,
3. and cost-effective
68. The main disadvantage is that the
1. Information may not be very accurate as
the test is time-sensitive.
2. It also provides limited information about
the urine as it is qualitative test and not a
quantitative test (for example, it does not
give a precise measure of the quantity of
abnormality).