13. Composition of urine
1-Water :95%.
2- Non protein nitrogenous compound 2.2%:
⢠Creatinine.
⢠Urea.
⢠Uuric acid.2.2%.
3-Dissolved salts and other ions as Na+, K+,H+,
Ca++,Cl-, phospate:2.8%
14.
15. Urine sample:
It must be analyzed within 1 hour of collection if held at
room temperature or else refrigerated at 2°â8°C for not
more than 8 hours before analysis.
The chemical changes which may occur in urine
specimens stored at room temperature include:
⢠Breakdown of urea to ammonia by bacteria, leading to
an increase in the pH of the urine. This may cause the
precipitation of calcium and phosphates.
⢠Destruction of glucose by bacteria.
⢠Precipitation of urate crystals in acidic urine. These
chemical changes can be slowed down by refrigerating
the urine at 2â8°C or adding preservatives.
20. Types of urine samples:
Morning
urine
sample:
24 hours
urine
sample
Mid-stream
urine
sample:
Random
urine
sample:
Urine is concentrated
Quantitative
for a culture
Not quantitative
Must stop
antibiotic 48
hrs. before
21. A) Physical examination of urine:
Volume:
Odor
Color
Specific gravity
Aspect (appearance):
Reaction (PH)
31. 2-Odor:
Odor interpretation
Aromatic =Uriniferous Normal urine odor
Ammoniacal On standing decomposition of urea by
bacteria ammonia
Acetone like odor = (fruity) ⢠Diabetic ketoacidosis
⢠Starvation
Offensive Bacterial infection
Mousy Phenylketonuria (PKU) inherited disorder
with deficiency of phenyl alanine
hydroxlase
Caramelized Maple syrup disease inherited disorder of
metabolism of branched chain amino
acids(leucine-isolucine & valine)
32. 3-Color:
Color Interpretation
Amber yellow Normal urine color
Pale yellow ⢠Very dilute urine
⢠Infants
⢠Diabetes mellitus (D.M.)
⢠Diabetes insipidus (D.I.)
⢠Increase fluid intake
Dark yellow ⢠Fever
⢠Hyperthyroidism
⢠Dehydration
Light brown
(tae like color)
Jaundice
Red ⢠trauma of urinary tract
⢠Porphyrinuria
Black Alkaptonuria
33. 4- Aspect=Appearance:
Normally, freshly urine transparent &clear.
Turbid urine:
⢠Pus =Pyuria.
⢠Red cells =hematuria
⢠Crystals (calcium phosphate or urate).
⢠Epithelial cells.
34. 5- Specific gravity:
⢠It is the density of urine compared with the density of distilled
water that is conveniently fixed as 1 at 20â° C.
⢠It measures the ability of the kidney to concentrate urine.
⢠It varies directly with the grams of solutes excreted in urine
and inversely with volume.
. Measured using Urinometer
36. Specific Gravity Interpretation
1.015 â 1.025 Normal urine
> 1.025 Physiologically:
Summer
First morning specimen.
Pathologically:
⢠Dehydration.
⢠Presence of glucose in urine (D.M.)
⢠Presence of protein in urine (Proteinuria).
⢠Shock.
⢠Heart failure.
<1.025 Physiologically:
High fluid intake.
Pathologically:
D.I.
37. 6-Reaction of urine(pH):
pH Interpretation
5 - 7 Normal urine
Alkaline
pH
⢠After meal.
⢠High citrus fruits and vegetables??.
⢠Bacterial colonization of urine
⢠Administration of certain drugs as sodium bicarbonate
⢠Metabolic and respiratory alkalosis
Acidic
pH
⢠High protein diet ????.
⢠Fever
⢠D.M.
⢠Metabolic and respiratory acidosis
38. B-Microscopic examination of urine:
Preparation of sample:
1- 5.0 ml fresh urine
2-Remove 4.9 ml supernatant fluid.
3-Place a drop of the sediment
4-microscope.
10 min - high speed
39. Constituents of the sediment:
Crystals
Casts
cells
Normally urine does not contain
⢠Red blood cells. N.R.=(0-2 RBCs/HPF).
⢠Pus cells. N.R.(0-2 WBCs/ HPF).
⢠Casts.(0-5 hyaline cast/LPF)
40. 1-Crystals:
According to the pHof urine we can classify the
crystals into:
Acidic urine:
⢠amorphous urate.
⢠uric acid.
⢠Na urate.
⢠calcium oxalate.
Alkaline urine:
⢠amorphous phosphate.
⢠calcium phosphate.
⢠triple phosphate.
⢠calcium carbonate.
⢠calcium oxalate.
ox
ph
urate Uric acid
41. 2-Cells:
In case of glomerulonephritis the urine
will contain red blood cells; pus cells
and casts (hyaline or granular casts).
42. 3-CASTS:
They are found in the lumen of the distal convoluted tubule
and collecting duct. They are the only elements found in the
urinary sediment that are unique to the kidneys.
43. C) Chemical examination of urine:
1-Proteins or Albumin: âŤŘ§ŮزاŮŮâŹ
Most proteins are too large to pass through
the glomeruli.
The glomeruli are negatively charged, so they
repel the negatively charged proteins.
when the glomeruli are damaged, proteins of
various sizes pass through them and appear
in the urine.
44. Appearance of proteins in urine is referred as
Proteinuria or Albuminuria which is a symptom of
Nephrotic syndrome (damage the
glomeruli capillary walls)
45. It is characterized by increased glomerular
permeability :
⢠Glomerulonephritis.
⢠toxins as gold .
⢠penicillamine.
Proteinuria results in decrease of serum albumin
concentration generalized edema.
46. 2- GLUCOSE:
Presence of more than the usual amount of glucose
in urine is called glucosuria.
a)A rise in blood glucose concentration
⢠Untreated diabetes mellitus.
⢠Glucose infusion.
b) rate of glucose reabsorption:
Tubular damage.
c) rate of glomerular filtration
During pregnancy.
48. 4-Blood:
Presence of blood in urine is called hematouria.
a)Infections as :
⢠Schistosoma haematobium.
⢠urinary tract infections (UTI).
b) Renal causes:
⢠Glomerulonephritis(InďŹammation of the glomeruli) .
⢠Renal tract stones.
⢠Kidney tumours.
c) Toxins or drugs as
⢠Phenols.
⢠Cyclophosphamide.
49. 5- Bile salts (bile acids):
They are sodium and potassium salts of bile
acids that are metabolic end products of
cholesterol metabolism (e.g.: Taurocholic
acid, Glycocholic acid, Deoxycholic acid).
They act as surfactants and help in the
digestion and absorption of fats.
They are normally excreted in bile to the
intestine so they are normally absent in urine.
The presence of bile salts in urine confirms
the presence of obstructive jaundice.
50. 6-Bile pigments (bilirubin):
Bilirubin is the metabolic end product of
hemoglobin metabolism.
Normal urine is free of bilirubin.
Plasma and hence urinary levels of bilirubin
increase when there is a :
⢠Biliary obstruction jaundice
⢠Hepatitis
⢠Liver cirrhosis.
51. 7) Nitrite:
Normal urine does not contain nitrite.
Presence of nitrite in urine urinary tract infections
(caused by nitrate reducing-bacteria)
54. 1) PROTEIN:
This test is based on the color change of the indicator
tetrabromophenol blue. A positive reaction is indicated by
a color change from yellow through green and then to
greenish-blue.
tetrabromophenol blue
55. 2) GLUCOSE:
. First, glucose oxidase catalyzes the formation of gluconic acid
and hydrogen peroxide from the oxidation of glucose.
A second enzyme, peroxidase, catalyzes the reaction of
hydrogen peroxide with potassium iodide chromogen to oxidize
the chromogen to colors ranging from blue through
greenishbrown, and brown to dark-brown.
KI
peroxidase
glucose oxidase
gluconic acid
56. 3) KETONE BODIES:
This test is based on the reaction of acetoacetic acid in the urine with
nitroprusside. The resulting color ranges from tan when no reaction
takes place, to purple for a positive reaction. Normal urine specimens
ordinarily yield negative results with this reagent.
57. 4) BLOOD:
This test is based on the pseudoperoxidase activity of hemoglobin
which catalyzes the reaction of tetramethylbenzidine and buffered
organic peroxide. The resulting color ranges from, greenish-yellow
through bluish-green to dark blue.
58. 5) NITRITE:
This test is based on the reaction of p-arsanilic acid and nitrite in urine
to form a diazonium compound. The diazonium compound in turn
couples with N- (l-naphthyl) ethylenediamine in an acid
medium and the resulting color is pink. Any degree of pink color is
considered positive.
59. 6) UROBILINOGEN:
The test is based on a diazotisation reaction of 4-
Methoxybenzene diazoniurn salt and urinary urobilinogen in a
strong acid medium. The color changes from pink to brown-red.
60. 7) BILIRUBIN:
This test is based on the coupling of bilirubin with 2.4-dichlorobenzene
diazonium salt in a strong acid medium. The color changes from light
tan to pinkish-purple. No bilirubin is detectable in normal urine by even
the most sensitive methods.
Since the bilirubin in samples is sensitive to light, exposure of the urine
samples to light for a long period of time may result in a false negative
test result.
61. 8) LEUCOCYTES:
This test reveals the presence of granulocyte esterases. The esterases
cleave a derivatized pyrazole amino acid ester to liberate derivatized
hydroxy pyrazole. This pyrazole then reacts with a diazonium salt to
produce a purple color.
esterases
diazonium salt
62. 9) REACTION (PH)
This test is based on double indicators (methyl red and bromothymol
blue), which give a broad range of colors covering the entire urinary pH
range. Colors range from orange through greenish yellow and green
to blue. This test indicates the pH values within the range of 5 to 9.
63. 10) SPECIFIC GRAVITY
This test is based on the pka(dissociation constant)
change of certain pretreated polyelectrolytes in relation to the ionic
concentration. In the presence of an indicator, the color changes
from deep blue in urine of low ionic concentration.
64. 1) test for albumin (heat coagulation
test):
Proteins in urine are coagulated (denaturated)
by heat
Procedure:
1) To a clean dry test tube, add 5 ml of urine
sample.
2) To a second tube, add 5 ml distilled water.
3) Heat both tube in boiling water bath for 5
minutes
4) Note the formation of turbidity
65. 2) Test for glucose (Benedictâs test):
Procedure:
1) To a clean dry test tube, add 1 ml of urine
sample.
2) Add 1 ml of Benedictâs reagent.
3) Mix well and heat both tube in boiling water
bath for 5 minutes.
4) Note the formation yellow to orange-red color.
66. 3) test for ketone bodies (rothera test):
Procedure:
1) To a clean dry test tube, add 2 ml of
urine sample.
2) Supersaturate with ammonium sulphate
powder.
3) Add 1 ml of 2% sodium nitroprusside
solution and mix well.
4) Add conc. Ammonia dropwise on the
wall of tube.
5) Note the formation violet ring.
67. 4) test for bile salts (hayâs sulphur test):
Procedure:
1) To a clean dry test tube, add 2 ml of
urine sample.
2) To a second clean dry test tube, add 2
ml water.
3) Sprinkle a little of sulphur powder on
the surface.
4) Sulphur remains on the surface in
normal urine but sinks down in the
presence of bile salts