lOMoARcPSD|5949070
3. Physical Exam of Urine
Clinical Microscopy (Our Lady of Fatima University)
StuDocu is not sponsored or endorsed by any college or university
Downloaded by John Ross Esturco (jresturco@gmail.com)
lOMoARcPSD|5949070
CLINICAL MICROSCOPY
PHYSICAL EXAMINATION OF URINE
1. COLOR
I. NORMAL URINE COLOR:
- pale yellow, yellow, or dark yellow
* Yellow Urine:
- because of the presence of Urochome,
a product of Endogenous Metabolism
- named by Thudichum in 1864
- pigment which causes the urine become yellow
- it also ↑ in Thyroid condition, in Fasting states,
or if the Urine stands @ RT
* Pink-Colored Sediments in the Urine:
- present in urines that have been refrigerated
- presence of Uroerythrin which attaches to the
Urates, producing a pink-color to the sediment
* Orange-Brown Urine:
- presence of Urobilin, from oxidation of Urobilinogen
- gives an orange-brown color to a urine that is not
fresh
II. ABNORMAL URINE COLOR:
a. DARK YELLOW / AMBER / ORANGE
- aside from signifying a normal concentrated urine, it
may also be cause of the presence of an abnormal
pigment called “Bilirubin”
- Bilirubin is suspected if yellow foam appears when
the urine is shaken. However, it will be detected
during Chemical Examination of Urine
- normal urine produces only a small amount of rapidly
disappearing foam when shaken, and a large amount
of foam indicates ↑ concentration of Protein
- A urine with Bilirubin may also contain Hepatitis
Virus
* Yellow-Orange Urine:
- Photo-oxidation of Urobilinogen to Urobilin
- administration of Phenazopyridine or Azo-Gantrisin
compounds to URTI patients
- urine with Phenazopyridine also produces yellow
foam when shaken, which can be mistaken for
Bilirubin
* Yellow-Green Urine:
- Photo-oxidation of Bilirubin to Biliverdin
b. RED / PINK / BROWN
* Red Urine:
- presence of RBCs in the urine
- other two substances Hemoglobin and Myoglobin
also produce a red urine with a (+) result in a chemical
test for Blood
> presence of RBCs: urine is ‘red and cloudy’
> presence of Hemoglobin and Myoglobin: urine is
‘red and clear’
- Distinguishing between Hemoglobinuria and
Myoglobinuria may be possible in examining the
patient’s plasma;
> Hemoglobinuria: ‘red plasma’ resulting from the in
vivo breakdown of RBCs
> Myoglobinuria: from breakdown of skeletal muscle
produces ‘clear plasma’ because it is more rapidly
cleared from the Plasma than Hemoglobin
- Urine containing Porphyrins also appear Red, a
product from the oxidation of Porphobilinogen which
is often referred to as ‘port-wine urine’
- other Non-pathogenic causes of red urine includes
Menstruation, Contamination, Ingestion of Highlypigmented foods, & Medications
- Eating Fresh Beets causes a red color in Alkaline
urine
- Ingestion of Black Berries can produce a red color in
Acidic Urine
- Medications such as Rifampin, Phenolphthalein,
Phenindione, and Phenothiazines produce red urine
* Reddish-Brown Urine:
- fresh urine with Myoglobin
- possibility of Hemoglobinuria being produced from
in-vitro lysis of RBCs
* Brown Urine:
- presence of RBC leading to oxidation of Hemoglobin
to Methemoglobin in Acidic Urine
- Oxidation of Hemoglobin to Methemoglobin
signifying Glomerular Bleeding in Fresh Urine
c. BROWN / BLACK
- Additional testing is recommended for Urine
specimens that turn Brown or Black on Standing and
have a (-) Chemical test result for Blood, in as much
they may contain Melanin or Homogenistic Acid
- Melanin is an oxidation product of the colorless
pigment called “Melanogen” produced in excess when
a Malignant Melanoma is present
- Homogenistic Acid, a metabolite of Phenylalanine,
imparts a black color to Alkaline urine from patients
with inborn error of metabolism called “Alkaptonuria”
- Medications producing Black/Brown urines include
Levodopa, Methyldopa, Phenol derivatives, &
Metronidazole
JOYCE ANN S. MAGSAKAY
OLFU—COLLEGE OF MEDICAL LABORATORY SCIENCE
Downloaded by John Ross Esturco (jresturco@gmail.com)
lOMoARcPSD|5949070
CLINICAL MICROSCOPY
PHYSICAL EXAMINATION OF URINE
d. BLUE / GREEN
- Bacterial infections including URTI by Pseudomonas
spp. and GITI infections resulting to ↑ Urinary Indican
- Ingestion of Breath Deodorizers (Clorets) can result
in Green Urine
- Medications such as Methocarbanol (Robaxin),
Methylene Blue, & Amitriptyline (Elavil) may cause
Blue Urine
- Phenol derivatives found in certain IV medications
produce Green Urine on Oxidation
- a purple-staining may occur in Catheter bags and is
caused by Indicant in the Urine or a Bacterial
infection, frequently caused by Klebsiella spp. or
Providencia spp.
2. CLARITY
- transparency or turbidity of a urine specimen
- reported as Clear, Hazy, Cloudy, Turbid, or Milky
I. NORMAL CLARITY:
- freshly voided urine is usually clear, particularly if it’s
a midstream clean-catch urine specimen
- precipitation of Amorphous Urates and Carbonates
may cause ‘white cloudiness’
CLARITY
Clear
Hazy
Cloudy
Turbid
Milky
TERM
No visible particulates, transparent
Few particulates, print easily seen through urine
Many particles, print blurred through urine
Print can’t be seen through urine
May precipitate or be clotted
II. NON-PATHOLOGIC TURBIDITY:
- presence of Squamous Epithelial cells and Mucus,
especially in women produces hazy but normal urine
- other Non-pathologic causes of Urine Turbidity
includes Semen, Fecal contamination, Radiographic
contrast media, Talcum powder, or Vaginal creams
- improper preservation of urine results in Bacterial
growth which increases turbidity but isn’t
representative of the actual specimen
- urine that are allowed to Stand; or are Refrigerated
may develop a Thick Turbidity due to the precipitation
of Amorphous Urates, Carbonates, & Phosphates
> Amorphous Phosphate and Carbnonates: produces
a ‘white ppt’ in Alkaline Urine
> Amorphous Urates: produce a ‘pink-brick dust
precipitate’ in Acidic Urine due to the presence of
Uroerythrin
III. PATHOLOGIC TURBIDITY:
- pathologic causes or Urine Turbidity includes
presence of RBC, WBC, and Bacteria caused by
infection or a Systemic Organ Disorder
- other causes includes abnormal amounts of Nonsquamous Epithelial cells, Abnormal Crystals, Lymph
fluid, Yeasts, & Lipids
- The clarity of a urine provides a key to the
Microscopic examination results, because the amount
of Turbidity should correspond with the amount of
material observed under the microscope
- Clear Urine is not always normal. However, with the
↑ sensitivity of the routine Chemical tests, most
abnormalities in the urine will be detected prior to the
Microscopic Analysis
- Current criteria used to determine the necessity of
performing a Microscopic examination on all urine
specimens include both Clarity and Chemical tests for
RBC, WBC, Bacteria, and Protein
3. SPECIFIC GRAVITY
- the density of a solution compared with the density
of a similar distilled water (SG = 1.000)
- the specific gravity of a urine is based on the kidney’s
ability to concentrate the Glomerular filtrate by
selectively reabsorbing essential chemicals and water
SPECIFIC GRAVITY
VALUE
SG of the Plasma filtrate entering the
Glomerulus
SG of Normal Urine Specimen
SG of Most random Urine Specimen
ISOSTHENURIC
HYPOSTHENURIC
HYPERSTHENURIC
1.010
1.002 to 1.035
1.015 to 1.030
1.010
<1.010
>1.010
- Measurement of SG is influenced by the size and
number of particles. Using Refractometer, it corrects
for the presence of substances that are not normally
present in the urine such as Glucose and Protein
* REFRACTOMETRY
- determines the concentration of dissolved particles
in a urine by measuring the Refractive Index
- Refractive Index is a comparison of the velocity of
light in air with the velocity of light in a solution
- the concentration of dissolved particles present in
the solution determines the velocity and angle at
which light passes through a solution
JOYCE ANN S. MAGSAKAY
OLFU—COLLEGE OF MEDICAL LABORATORY SCIENCE
Downloaded by John Ross Esturco (jresturco@gmail.com)
lOMoARcPSD|5949070
CLINICAL MICROSCOPY
PHYSICAL EXAMINATION OF URINE
- it utilizes the use of a Prism to direct a Specific
Wavelength of Daylight against a manufacturercalibrated Specific Gravity Scale
- it provides the distinct advantage of determining
Specific Gravity using a small volume of Urine
- Temperature is compensated @ 15°C-38°C
- Corrections for Glucose and Protein must be
calculated by subtracting 0.003/gram of Protein
present while 0.0004/gram of Glucose Present
- Abnormally High results—above 1.040 are seen in:
> patients who have recently undergone an
IV Pyelogram which caused by the excretion of the
injected Radiographic contrast media.
> Patient who are receiving Dextran or other High
Molecular Weight IV fluids (Plasma Expanders)
* URINOMETRY
- consists of a weighted float attached to a scale that
has been calibrated in terms of urine SG
- the weighted float displaces a volume of liquid equal
to 1.000 in distilled water
- the additional mass provided by the dissolved
substances in urine causes the float to displace a
volume of urine smaller than that of distilled water
- the level to which the urinometer sinks represent the
urine’s SG
- not recommended by CLSI
4. OSMOLALITY
- Osmolarity of a solution can be determined by
measuring a property that is mathematically related to
the number of particles in a solution (Colligative
Property) and comparing this value with the value
obtained from the pure solution
- unlike Refractometry, it is only influenced by the
number of particles
- Osmole is defined as 1g MW of a substance divided
by the # of particles into which it dissociates
PROPERTY
Freezing
Point
Boiling
Point
Vapor
Pressure
Osmotic
Pressure
NORMAL PURE
WATER POINT
* HARMONIC OSCILLATION DESITOMETRY
- based on the principle that “the frequency of a sound
wave entering a solution changes in proportion to the
density of the solution”
- this technique was originally used in early automated
urinalysis instruments
- the addition of Reagent Strip Analysis for SG has
replaced this technique
* REAGENT STRIP SPECIFIC GRAVITY
- Principle: pKa (dissociation constant) of a
Polyelectrolyte in an Alkaline Urine
- the Polyelectrolyte ionizes, releasing Hydrogen ions
in proportion to the number of ions in the solution
- the ↑ the conc. of urine, the more hydrogen ions are
released, thereby lowering the Ph
- Indicator: Bromthymol Blue
- As SG ↑, the indicator changes from blue (1.000Alkaline) through shades of green, to yellow (1.030Acid)
5. ODOR
URINE
Freshly voided urine
Urine stands for a long time
Urine with Bacterial infxn
Urine with Diabetic Ketones
Maple Syrup Disorder
Phenylketonuria
Tyrosinemia
Isovaleric Acidemia
Methionine Malabsorption
Contamination
Ingestion of Onions, Garlic,
Asparagus
EFFECT OF 1 MOLE
OF SOLUTE
0°c
Lowered 1.86°c
100°c
Raised 0.52°c
2.38 mm/Hg @ 25°c
Lowered 0.3mm/Hg @ 25°c
0 mm/Hg
Increased 1.7 x 109 mm/Hg
JOYCE ANN S. MAGSAKAY
OLFU—COLLEGE OF MEDICAL LABORATORY SCIENCE
Downloaded by John Ross Esturco (jresturco@gmail.com)
ODOR
Aromatic odor
Ammonia odor
Ammonia-like odor
Sweet/Fruity odor
Maple Syrup odor
Mousy odor
Rancid odor
Sweaty feet-like odor
Cabbage-like odor
Bleach odor
Pungent odor