3. The Urinary System
Organs of the urinary system:
Kidneys
Ureters
Urinary bladder
Urethra
Kidney function - removes waste products
from the blood stream and excess water
Urinary bladder stores urine, and ureters,
bladder and urethra make up the urinary tract 3
5. Formation of Urine
Three processes The nephron:
of urine allows for
formation: reabsorption of
glomerular filtration
water and
tubular reabsorption
electrolytes
tubular secretion plays a vital role
in maintaining
normal fluid
balance
5
6. Nephron
- functional unit of the kidney where urine is
formed.
STAGES IN URINE FORMATION:
1.Filtration
2.Reabsorption
3.Secretion
14. Nephron
- functional unit of the kidney where urine is
formed.
STAGES IN URINE FORMATION:
1.Filtration
2.Reabsorption
3.Secretion
15. Urinalysis
Specific Objectives:
Physical Characteristics
Normal pH
Specific Gravity ranges
Presence of abnormal substances
in the urine specimens
16. Physical Composition and Chemical
Properties
Urine
95% water
5% waste products
Other dissolved chemicals
Urea, uric acid, ammonia, calcium, creatine,
sodium, chloride, potassium, sulfates,
phosphates, bicarbonates, hydrogen ions,
urochrome, urobilinogen
16
17. Urinalysis
• a physical and/or chemical
examination of the urine.
• It consists of a battery of chemical and
microscopic tests to screen for:
• urinary tract infections
• renal disease, and
disease
• diseases of other organs that result
in the appearance of abnormal
metabolites (break-down
products) in the urine.
18. Urinalysis
• can reveal diseases that have gone unnoticed
because they do not produce striking signs or
symptoms.
• Examples include diabetes mellitus,
various forms of glomerulonephritis, and
chronic urinary tract infections.
• In other urinary diseases with symptoms, a
urinalysis can help to confirm of rule out some
diseases.
19. TESTS
• Qualitative Tests for Normal Constituents
• Urea Test
• Uric Acid
• Indican Test (Decompositon of
Tryptophan)
• Qualitative Tests for Pathological Constituents
• Gunning’s Test (Ketone)
• Benedict's Test (Glucose)
• Exton’s Test (Albumin)
• Smith’s Test (Bile pigments)
20. SPECIMEN COLLECTION
• A "clean-catch" urine sample is
performed by collecting the sample
of urine in midstream.
• Men or boys should wipe clean the
head of the penis.
• Women or girls need to wash the
area between the lips of the vagina
with soapy water and rinse well.
• A small amount of urine should
initially fall into the toilet bowl before
it is collected (this clears the urethra
of contaminants).
• Then, in a clean container (properly
labeled with the name of the patient
and date), catch about 1 to 2
ounces of urine and remove the
container from the urine stream.
21. Specimens Types
Varies in method used and in
time frame in which to collect
specimen
Types of specimens:
Random
First morning
Clean catch midstream
Timed
24 hour
21
22. Specimens Types
(cont.) Random – most common, taken
anytime of day
First morning – has a greater
concentration of substances, taken
in morning
Clean catch midstream – genitalia is
cleaned, urine is tested for
microorganisms or presence of
infection
Timed – specific time of day, always
discard first specimen before timing
24 hour – used for quantitative and
qualitative analysis of substances 22
23. SPECIMEN COLLECTION
• For an infant, thoroughly wash the area
around the urethra.
• Open a urine collection bag (a plastic bag
with an adhesive paper on one end), and
place it on the genital area.
• For males, the entire penis can be placed
in the bag and the adhesive attached to
the skin.
• For females, the bag is placed over the
labia majora. Place a diaper, check the
infant frequently and remove the bag after
the infant has urinated into it.
• The urine is then drained into a labeled
container.
24. Urinalysis
Evaluation of urine to obtain information
about body health and disease
Three types of testing:
Physical
Chemical
Microscopic
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25. Physical Examination of
Urine
Visual examination of physical
characteristics
Color and turbidity
Volume
Odor
Specific gravity
The refractometer or a reagent
strip is used to measure
specific gravity
Refractometer
Reagent Strips
25
26. MACROSCOPIC URINALYSIS
• Clearing of the specimen after addition
of a small amount of acid indicates that
precipitation of salts is the probable
cause of turbidity.
• A red or red-brown (abnormal)
color could be from a food dye,
eating fresh beets, a drug, or the
presence of either hemoglobin or
myoglobin.
• If the sample contained many red
blood cells, it would be cloudy as
well as red.
27. MACROSCOPIC
URINALYSIS
• The first part of a urinalysis is direct
visual observation. Normal, fresh
urine is pale to dark yellow or
amber in color and clear.
• Normal urine volume is 750 to
2000 ml/24hr.
• Turbidity or cloudiness may be
caused by excessive cellular
material or protein in the urine or
may develop from crystallization or
precipitation of salts upon standing
at room temperature or in the
refrigerator.
28. Normal Values of Urine
Normal values of various
elements have been
established
Average adult daily urine
output is 1250 mL/24
hours
Intake and output should
be approximately the
same
28
31. • The glomerular filtrate of blood
plasma is usually acidified by renal
pH tubules and collecting ducts from a
pH of 7.4 to about 6 in the final
urine.
• However, depending on the acid-
base status, urinary pH may range
from as low as 4.5 to as high as
8.0.
8.0
• The change to the acid side of 7.4 is
accomplished in the distal
convoluted tubule and the
collecting duct.
32. • (which is directly proportional to
urine osmolality which measures
Specific solute concentration) measures
urine density, or the ability of the
gravity kidney to concentrate or dilute the
urine over that of plasma.
• Specific gravity between 1.002 and
1.035 on a random sample should
be considered normal if kidney
function is normal.
• Since the sp gr of the glomerular filtrate
in Bowman's space ranges from 1.007
to 1.010, any measurement below this
1.010
range indicates hydration and any
measurement above it indicates
relative dehydration.
dehydration
33. Specific Gravity (sp gr)
• If sp gr is not > 1.022 after a 12 hour
period without food or water
• renal concentrating ability is
impaired
• In end-stage renal disease, sp gr
tends to become 1.007 to 1.010.
• Any urine having a specific gravity over
1.035 is
• either contaminated,
• contains very high levels of glucose
35. -
Apply Your Knowledge Answer
What is the specific gravity shown on
this refractometer screen?
The specific
gravity
shown
here is
1.030
35
36. Chemicals Found in
Urine
Ketone bodies – may indicate that patient is following
a low carbohydrate diet or that patient has conditions
such as starvation
pH – provides information about metabolic status, diet,
medication or several conditions
Blood (hematuria) – may indicate patient is
menstruating, have urinary tract infection or trauma
36
37. Chemicals Found in
Urine (cont.)
Bilirubin or urobilinogen – first signs
of liver disease
Glucose – common in patients with
diabetes
Protein – usually indicates renal
disease
Nitrite – suggests bacterial infection
Leukocytes – urinary or renal
infection
Phenylketones – indicates PKU
37
38. Microscopic Examination
of Urine
Microscopic examination used to view elements not
visible without microscope
Centrifuge spins urine to cause heavier substances to
settle to the bottom
• Cells • Casts
• Crystals • Yeasts
• Parasites
• Bacteria
38
39. Glucose test
• Benedict’s test
• Aqueous glucose is mixed with
Benedict's reagent, a solution of
copper sulfate, sodium hydroxide, and
tartaric acid.
• The mixture is heated.
• Carbohydrates which react with
Benedict's reagent to reduce the blue
copper (II) ion to form a brick red
precipitate of copper (I) oxide are
classified as reducing sugars.
41. Glucose
• Less than 0.1% of glucose normally
filtered by the glomerulus appears in urine
(< 130 mg/24 hr).
• Glycosuria (excess sugar in urine)
diabetes
generally means
mellitus.
42. • Exton’s Test
• There are several acids
Protein which can be used to
precipitate proteins -
sulfosalicylic,
trichloroacetic, nitric, and
acetic acids.
• Sulfosalicylic acid (SSA) is
the most frequently used acid
test because it does not
require the use of heat.
• Exton’s reagent is 5%
sulfosalicylic acid in a
43. To perform the SSA procedure mix equal parts of patient urine and the reagent. Rate the
amount of turbidity according to the following scale:
44. Interpretation
• In rough terms, trace positive
results (which represent a slightly
hazy appearance in urine) are
equivalent to 10 mg/100 ml or
about 150 mg/24 hours (the upper
limit of normal).
• 1+ corresponds to about 200-500
mg/24 hours
• a 2+ to 0.5-1.5 gm/24 hours
• a 3+ to 2-5 gm/24 hours
• a 4+ represents 7 gm/24 hours or
greater.
45. • Normally, only small plasma
Interpretation proteins filtered at the glomerulus
are reabsorbed by the renal
tubule.
• Normal total protein excretion
does not usually exceed 150
mg/24 hours or 10 mg/100 ml in
any single specimen.
• More than 150 mg/day is
defined as proteinuria.
• Proteinuria > 3.5 gm/24 hours
is severe and known as
nephrotic syndrome.
46. Apply Your Knowledge
A urine analysis has
detected that a patient has
protein in his urine. Why is
this important?
46
47. -
Apply Your Knowledge Answer
A urine analysis has detected that a
patient has protein in his urine. Why
is this important?
Protein in the urine usually indicates
renal disease
47
48. Ketones
Gunning’s Test
• Ketones (acetone, aceotacetic acid, beta-
hydroxybutyric acid) resulting from either
diabetic ketosis or some other form of
calorie deprivation (starvation)
• Shows positive test for:
acetaldehyde and methyl ketones
49. Ketones
Gunning’s Test
• Detection of COOH group is possible
through its transformation to an ester in
reaction with alcohol.
• The esters have characteristic smell of
flowers or fruits
• It should appear the yellow precipitate of
iodoform with characteristic smell
• Ketones Normal:There are no ketones in
your blood or urine.
• Abnormal:Ketones are present in your
blood or urine.
50. • . Indications of a positive test:
The formation of a yellow precipitate or suspension of
iodoform is a positive test
a negative test (left) and a positive test (right)
53. emerald green at the point of contact between urine sample
and alcoholic iodine mixture
Bilirubin – green
Bilicyanine – blue
Choletelin - yellow
54. • Smith’s Test should be conducted to
determine whether bilirubin is present in the
urine
(i.e., bilirubinuria).
• Urobilinogen is formed by intestinal bacteria
from the breakdown of conjugated bilirubin,
and it is usually excreted in feces.
• However a small amount may be
reabsorbed and excreted in urine.
55. • A positive test response indicates normal
enterohepatic circulation of biliary
pigments. High concentrations of biliary
pigments may occur in hemolytic crisis, or
cases of hepatic or intestinal dysfunction.
