General Urine Examination

General Urine Examination
Hussein A. Abid 
Lecture: 09 and 10
Middle Technical University
Technical Institute of Baquba
Medical Laboratory Technology Department
Academic year 2019-2020 – Spring semester
Medical Laboratory Technology & Quality Control Applications
Module code: MLT113
L.No.: MLT113-20-T-09-10

General Urine Examination (GUE)
• Routine screening test
• Usually done as a part of a physical examination,
during preoperative testing, and upon hospital
admission.
• It is used for the diagnosis of infections of the
kidneys and urinary tract and also in the
diagnosis of diseases unrelated to the urinary
system.
01 Hussein Adil Abid - 2020

• Consists of FIVE (or mostly three) parts:
1. Physical (or macroscopic) examination
2. Chemical examination
3. Microscopic examination
4. Culture & sensitivity
5. Cytopathology examination

Hussein Adil Abid - 202003

Physical & chemical urine exam
• Appearance
• Color
• Odor
• Specific gravity
• pH
• Leukocyte esterase
• Nitrate
• Protein
• Glucose
• Ketones
• Urobilinogen
• Bilirubin

• Appearance: refers to the clarity of the fluid.
Deviations from the normal appearance of urine may
indicate the presence of infection or hematuria.
• Color: correspond to the specific gravity of the urine.
There are many factors which can affect the color of
the urine, including food, drugs, and various
conditions.

Appearance
description
Color
description
Normal: Clear
to slightly hazy
Normal: Light
yellow to
amber

• Odor: The normal odor of urine, aromatic, is due to its
acidic content. Various conditions, medications, and
foods may cause changes in odor of the urine.
• Specific gravity (SG): is a measure of the concentration
of the urine compared to the concentration of water,
which is 1.000 g/cm3. The higher the SG, the more
concentrated the urine.

• SG: This test value is an indication of the kidneys’ ability to
concentrate and excrete urine.
• The SG is normally lower in the elderly due to a decreased
ability to concentrate urine.
• There is a condition, known as fixed SG, in which the SG
remains at 1.010, without variance from specimen to
specimen. This is usually indicative of severe renal
damage.
• Normal SG range: 1.005 - 1.030 (or 1.015 - 1.025)

Possible causeUrine odor
Type-1 diabetes mellitusFruity smell
UTIFishy
UTI caused by Pseudomonas or ProteusAmmonia
Maple Syrup Urine diseaseBurnt sugar
Food (asparagus, garlic)Musty

• pH (or reaction): provides information regarding the
acid-base status of the patient (normally, 4.6-8.0).
• Urine is considered alkaline when the pH is greater
than 7.0, and is found in such conditions as urinary
tract infection. When the urine pH is less than 7.0, or
acidic in nature, the cause may be such problems as
diarrhea or starvation.
• There is an inverse relationship between the pH of the
urine and the ketone (acetone) level in the urine.

• Leukocyte esterase (LE): is an enzyme released from
white blood cells when bacteria are present in the
urine.
• Testing the urine for LE is considered a screening test
for the presence of white blood cells in the urine.
• A positive reaction warrants further investigation to
determine whether a urinary tract infection truly
exists.

• LE test has been found to be very sensitive, meaning
false-negative findings are extremely rare. Thus, a
negative dipstick finding requires no further
evaluation, unless the patient demonstrates signs and
symptoms of a urinary tract infection.
• Any positive findings with this test should be verified
by a urine culture.
• Normal LE result: Negative

• Nitrate: is normally found in the urine (derived from
dietary metabolites).
• When gram-negative bacteria are present in the urine,
nitrate is converted to nitrite.
• The presence of nitrite in the urine, then, is an indication
that bacteria are also present.
• This test is used in conjunction with a dipstick test for
leukocyte esterase to screen for the presence of bacteria
during a routine urinalysis.

• It is important to note that the presence of some types of
bacteria do not lead to a positive nitrite. Thus, a negative
nitrite does not rule out the presence of a urinary tract
infection, especially if the patient is symptomatic.
• The conversion of nitrate to nitrite by bacteria requires the
microorganism to be in contact with the nitrate for some
time. Thus, the test is best conducted on the first urine
specimen of the morning. Any positive findings with this
test should be verified by a urine culture.
• Normal nitrate result: Negative

• Protein: In the individual with normal renal function, there
is no protein in the urine. This is due to the glomerular
filtrate membrane of the kidney being impervious to the
large protein molecules.
• In the case of renal dysfunction, as in glomerulonephritis,
the membrane is damaged, allowing the protein to pass
through and be excreted in the urine.
• Thus, this test is one way to assess the patient for renal
disease.

• It should be noted, however, that a small percentage
of the population may have what is known as
orthostatic or postural proteinuria, which is a benign
condition. However, if random urine samples are
consistently positive for protein, it is suggested that
further testing, including the collection of a 24-hour
urine sample, be conducted.
• Normal protein result: Negative

• Glucose: As a part of the routine urinalysis, the urine is
screened for the presence of glucose.
• This screening is typically accomplished through use of a
reagent strip is dipped into the urine sample. The chemical
reaction results in color changes which correspond to the level
of glucose in the urine.
• Normally, there should be no glucose present in the urine,
although occasionally a trace amount will occur during
pregnancy. Should glucose be found in the urine (usually when
serum glucose is >180 mg/dL), a condition known as glycosuria,
diabetes mellitus is suspected. However, further testing must
be done to positively diagnose this condition.

• Ketone bodies: As fatty acids are metabolized, three
ketone bodies are formed and later excreted in the
urine: acetoacetic acid, acetone, and beta-
hydroxybutyric acid.
• Thus, testing for the presence of ketones in the urine
(ketonuria) is assistive in the diagnosis of diabetes
mellitus, as well as in evaluating conditions associated
with ketoacidotic states, such as starvation.
• Normal ketones result: Negative

• Urobilinogen: Bilirubin, which is one of the components of
bile, is formed in the liver, spleen, and bone marrow. It is
also formed as a result of hemoglobin breakdown.
• One type of bilirubin, conjugated (direct) bilirubin, is
changed into urobilinogen by intestinal bacteria in the
duodenum.
• The majority of urobilinogen is excreted in the stool. The
liver reprocesses the remaining urobilinogen into bile.
• A very small amount is excreted in the urine

• An increase in urobilinogen is indicative of hepatic
dysfunction or a hemolytic process.
• Urobilinogen levels are typically highest during the
early to mid-afternoon. Thus, should dipstick testing
for urobilinogen be positive, the collection of a 2-hour
urine would be most appropriate between 1 and 3
P.M.
• Normal urobilinogen in urine: Negative or 0.1–1.0
Ehrlich units/dL

• Bilirubin: There are three types of bilirubin: total, direct
(conjugated), and indirect (unconjugated).
• Normally, direct, or conjugated, bilirubin is excreted by the
gastrointestinal (GI) tract, with only minimal amounts
entering the bloodstream.
• Direct bilirubin is water soluble and is the only type of
bilirubin able to cross the glomerular filter.
• Although it is the only type of bilirubin which could be
found in the urine, it is usually not detectable in the urine,
since it is converted to urobilinogen in the intestine.

• However, should jaundice occur due to obstruction or liver
disease, the direct bilirubin is unable to reach the GI tract.
• It instead enters the bloodstream, where it is eventually
filtered out by the kidneys and excreted in the urine.
• Thus, an increased level of direct bilirubin in the urine is
indicative of some type of hepatic or obstructive problem.
• Normal bilirubin in urine: negative or ≤0.2 mg/dL

Urine strip
• Use a fresh, well-mixed, uncentrifuged urine.
• Hold the reagent strip by the opposite end from the test
areas and dip the stick into the specimen so that all test
areas are immersed in the specimen. Remove the stick
immediately. Prolonged immersion in the sample may wash
out the test reagents.
• Hold strip in a horizontal position and run the edge of the
strip against the rim of the urine container or touch the long
edge of the strip to absorbent toweling to remove excess
urine (do not blot the strip). Maintain the strip in a horizontal
position to prevent mixing of reagent chemicals.

Urine strip
• If you are using a dipstick reader, place the strip immediately
onto the tray of the reader.
• Replace the cap on the container to prevent deterioration of
remaining strips
• If you are reading the tests manually, proceed with these
instructions:
• Observe the reagent pads at the specified time periods. Color
changes that occur after the stated maximum read time are not
valid.
• Hold the strip close to the chart and compare the colors to read
the results. A good light source facilitates accurate reading.

Microscopic urine exam
• Microscopic examination of sediment in the urine
includes observation of:
• Bacteria
• Casts
• Crystals
• Blood cells (red blood cells and white blood cells)
• Yeast, parasites, and sperms.

• Bacteria: Tests for the presence of leukocyte esterase and
nitrites in the urine are conducted to determine whether
bacteria are present in the urine. Bacteria may also be
noted via the microscopic examination of the urine.
• Should bacteria be found during a routine urinalysis,
culture, and sensitivity testing of the urine should be done
to determine the organism and to provide assistance in
determining appropriate antimicrobial therapy.
• Normal result: None

• Casts: Casts are collections of gel-like protein material which
result from the agglutination of cells and cellular debris. They
form in, and take the shape of, the renal tubules.
• Epithelial cells in the renal tubules are the components of
epithelial casts. Fatty casts are formed from fat droplets. When
the cellular material in epithelial cells and white blood cells
breaks down, the resulting granular particles form granular
casts. Hyaline casts are formed from protein, and thus indicate
the presence of proteinuria.
• Normal result: None

• Crystals: A few crystals present in the urine have little
clinical significance.
• However, it is problematic when numerous crystals form,
resulting in the formation of renal stones. For example,
numerous calcium oxalate crystals, resulting from
hypercalcemia, may form calcium oxalate stones. Knowing
the composition of the renal stone aids the health-care
provider in determining appropriate treatment modalities.
• Normal result: None of very few

Uric acid looks often like leave shaped; they are often yellow to orange-brown in
color. Under polarized microscopy they exhibit birefringence and many colors.

Calcium Oxalate is also a common crystal found in patient’s urine. They
have different shapes, like dumb-bell and the most commonly ones, the
square shapes. They look shiny and bright too.

Sulfonamide crystals form primarily in acid urine. The
shape and color of these crystals are extremely
variable, depending on the particular sulfonamide
being administered to the patient

Tyrosine crystals are not normally found in urine. They are products of protein metabolism
and appear in urine of people with tissue degeneration or necrosis (acute liver disease,
severe leukemia, typhoid fever, and smallpox). They are present only when urine is acid.
They are colorless to yellowish brown, needle shaped crystals and have a fine silky
appearance. Tyrosine crystals usually appear in urinary sediment together with leucine
crystals

Triple phosphate crystals, resemble prisms or "coffin lids". They are
found normally in alkaline or neutral urine. They are colorless

Cystine, an amino acid, is an abnormal finding in urine. Rarely seen, these crystals are
found in acid urine and are seen as thin, colorless, hexagonal plate

Calcium phosphate crystals assume various forms including the rosette and pointed finger
forms shown here with bright field microscopy (160X magnification). They appear most
often in alkaline urine

Calcium oxalate

Amorphous phosphates appear in neutral to
alkaline urine as fine, colorless or slightly
brown granules. White precipitate is observed
on centrifugation
Amorphous urates appear as fine pink or
brownish-tan granules They are salts of
uric acid and are normally found in acid
or neutral urine

• RBCs: The microscopic examination of sediment also serves to
determine whether any blood is present in the urine, a condition
known as hematuria.
• The urine is observed for both red blood cells and red blood cell
casts. When red blood cells are present in the urine, it usually
indicates damage to the renal glomeruli, which allows red blood cells
to enter the urine.
• Since there are several interfering factors, such as trauma incurred
during catheterization, which might also cause blood to be present in
the urine, it is suggested that a fresh urine specimen be collected and
the presence of blood be verified.
• Normal result: RBCs (0–2 per high-power field or HPF), Casts (None).

• WBCs: A few white blood cells are normally found in the
urine.
• If more than five white blood cells per high-power field are
present, a urinary tract infection should be suspected and
further testing conducted.
• White blood cell casts are aggregates of white blood cells
which collect in the renal tubules. These casts are seen
most often in patients with acute pyelonephritis.
• Normal result: WBCs (4–5 per high-power field or HPF),
Casts (None).

• Yeasts and hyphae: mostly Candida spp. conlonise
bladder, urethra, or vagina.
• Parasites/ova/sperm: Schistosoma haematobium,
Trichomonas vaginalis, Enterobius vermicularis,
Echinococcus granulosus, Wuchereria bancrofti, and
Onchocerca volvulus.
• Normal result: None.

Branching budding yeast cells with
pseudohyphae in urine

Schistosoma haematobium ovum Enterobius vermicularis ova
Trichomonas vaginalis trophozoite

NOTES
Bacteria
- Five bacteria/HPF represents 100,000 CFU/ml
- Diagnostic for Urinary Tract Infection
Men: Any bacteria
Women: 5 or more bacteria per hpf
Samples after TWO hours of collection should not be accepted for
examination

General Urine Examination

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