CHAPTER
16
Collecting,
Processing, and
Testing Urine
Specimens
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-2
Learning Outcomes
16.1 Describe the characteristics of urine, including
its formation, physical composition, and
chemical properties.
16.2 Explain how to instruct patients in specimen
collection.
16.3 Identify guidelines to follow when collecting
urine specimens.
16.4 Describe proper procedures for collecting
various urine specimens.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-3
Learning Outcomes (cont.)
16.5 Explain the process of urinary catheterization.
16.6 List special considerations that may require
you to alter guidelines when collecting urine
specimens.
16.7 Explain how to maintain the chain of custody
when processing urine specimens.
16.8 Explain how to preserve and store urine
specimens.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-4
Learning Outcomes (cont.)
16.9 Describe the process of urinalysis and its
purpose.
16.10Identify the physical characteristics present
in normal urine specimens.
16.11Identify the chemicals that may be found in
urine specimens.
16.12Identify the elements categorized and
counted as a result of microscopic
examination of urine specimens.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-5
Introduction
• Routine analysis of a urine specimen
– Noninvasive
– Used to diagnose significant conditions
• Medical assistant
– Learn about types of urine specimens
– Instruct or assist patient in collection of a
sample
– Learn to process urine specimens
– Learn about normal/abnormal components of
urine
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-6
Role of the Medical Assistant
• Collect, process, and
test urine samples
• Knowledge necessary
– Anatomy and
physiology of kidneys
– How urine is formed
– Normal components of
urine
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-7
Role of the Medical Assistant
• Safety
– Standard Precautions
– PPE as needed
– Handle and dispose of
specimens properly
– Dispose of used
supplies and equipment
properly
– Sanitize, disinfect,
and/or sterilize reusable
equipment
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-8
Anatomy and Physiology of the Urinary System
• Organs
– Kidneys – remove excess
water and waste products
– Ureters – drain urine into
bladder
– Bladder – stores urine
– Urethra – drains urine to
outside of the body
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-9
Formation of Urine
• Nephron
– Functional unit of the
kidney
– Removes end
products of
metabolism
– Allows for
reabsorption of water
and electrolytes
• Processes in urine
formation
– Glomerular filtration
– Tubular
reabsorption
– Tubular secretion
– Maintains normal fluid
balance
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-10
Physical Composition and Chemical Properties
of Urine
• 95% water
• 5% waste products
• Other dissolved
chemicals
–
–
–
–
–
Urea
Uric acid
Ammonia
Calcium
Creatinine
–
–
–
–
–
Sodium
Chloride
Potassium
Sulfates
Phosphates





Hydrogen ions
Urochrome
Urobilinogen
A few RBCs
A few WBCs
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-11
Apply Your Knowledge
1. What knowledge is needed by the medical assistant
related to collecting, processing, and testing urine
specimens?
ANSWER: The medical assistant needs to know the anatomy and
physiology of the urinary system, how urine is formed, and normal
components of urine.
2. Components of normal urine include
A. urea, uric acid, and ammonia.
B. chloride, potassium, and sugar.
C. red blood cells, sperm, and H2O2
D. hydrogen ions, urochrome, and
uranium.
ANSWER:
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-12
Obtaining Specimens
• General collection guidelines
– Follow the procedure for specified test
– Use an appropriate specimen container
– Label the specimen container correctly
– Explain the procedure to patient
– Wash your hands before and after the
procedure; wear gloves during the procedure
– Complete all necessary paperwork
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-13
Specimen Types
• Quantitative analysis – measures
amount of a specific substance
in the urine
• Qualitative analysis – simply
determines if a substance is
present in the urine
• Types vary in the method used to collect a
specimen and in the time frame in which to
collect a specimen
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-14
Specimen Types (cont.)
• Random urine
specimen
– Most common
– Obtained any time
during the day
• First morning
specimen
– Contains greater
concentration of
substances
• Clean-catch
midstream
– Used for culturing
urine
– External genitalia must
be cleansed
– Discard small amount
of urine prior to
collecting specimen
– Can also obtain by
catheterization
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-15
Specimen Types (cont.)
• Timed urine specimen
– Discard first specimen
– Collect all urine for specified time
– Refrigerate
• 24-hour specimen
– Collected as a timed specimen
• Both are used for qualitative and
quantitative analysis
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-16
Catheterization
• Urinary catheter – a
plastic tube inserted
to provide urinary
drainage
• Catheterization –
procedure by which
the catheter is
inserted
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-17
Catheterization (cont.)
• Reasons for catheterization
– Relieve urinary retention
– Obtain a sterile urine specimen
– Measure the amount of residual urine
– Obtain a specimen if patient cannot
void
– Instill chemotherapy
– Empty bladder before and during
procedures
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-18
Catheterization (cont.)
• Drainage catheters
– Indwelling urethral (Foley) catheter – bladder
– Retention catheter – renal pelvis
– Ureteral catheter – drainage through a wound
into the bladder (cystostomy tube)
– Straight catheter – bladder
• Splinting catheter – inserted after repair
of ureter
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-19
Catheterization (cont.)
• Not a routine procedure due to risk of
infection
• Not typically performed
by medical assistants
– Check scope of practice
– Assemble supplies –
catheterization kits
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-20
Special Considerations
• Male and female patients
– Differences in collecting
clean-catch midstream specimen
– Questions during history
• Pregnant patients
– Frequency
– Prone to urinary tract infection
– Urine checked for glucose and protein
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-21
Special Considerations (cont.)
• Elderly
– Bladder muscles
weaken
– Uterine supports
weaken – pulls on
bladder
– Loss of bladder control
– May need assistance
in obtaining a
specimen
– Repeat explanation as
necessary
• Pediatric patients
– Involve child if
possible
– Questions
•
•
•
•
•
Diaper rash?
Excessively thirsty?
Difficulty urinating?
Cry when urinating?
How many diapers a
day?
• Change in bladder
control?
• Problems toilet
training?
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-22
Establishing Chain of Custody
• Do not alter
• Examine specimen
established procedure
and check
temperature
• Positively identify
patient
• Complete
• Explain procedure
documentation
and have patient sign
a consent form
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-23
Preservation and Storage
• Chemical, physical, and microscopic changes
occur if urine is left at room temperature for
more than 1 hour
• Preservation
– Refrigeration
Specimens
only
• Prevents growth for 24 hours
• Return to room temperature before testing
– Chemical preservatives
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-24
Apply Your Knowledge
A patient has returned to the office and is complaining of
not being able to empty her bladder fully after her
hysterectomy. The physician has asked you measure
the patient’s residual urine. How do you do this and why?
ANSWER: A residual urine is done to measure the amount of urine in
the bladder after voiding. You will ask the patient to empty her
bladder and then perform a straight catheterization to measure any
urine remaining in her bladder.
Correct!
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-25
Urinalysis
• Evaluation of urine to obtain information
about body health and disease
• Types of testing
– Physical
– Chemical
– Microscopic
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-26
Urinalysis (cont.)
• Values
– Negative or none, normal,
or a range of concentration
– Within normal limits
indicate health and normality
– Screening test – must have
follow-up testing
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-27
Urinalysis (cont.)
• Average adult daily
urine output is 1250
mL/24 hours
• Intake and output
should be
approximately the
same
• Dysfunctions of other
body systems can
affect urinary function
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-28
Physical Examination and Testing of
Urine Specimens
• Check label
• Check for visible
contamination
• Check time since
collection
• Visual examination
– Color
– Volume
• Normal
• Oliguria
– Odor
– Specific gravity
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-29
Physical Examination and Testing of
Urine Specimens (cont.)
• Visual examination
– Color/turbidity – pale yellow to dark
amber; clear
– Volume
• Normal range – 600–1800 mL/24 hours
• Oliguria – insufficient production of urine
• Anuria – absence of urine production
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-30
Physical Examination and Testing of
Urine Specimens (cont.)
– Odor
• Distinct,
aromatic
• Standing at
room
temperature –
ammonia
• Affected by
disease and
foods
– Specific gravity
• 1.002 to 1.028
• Fluctuates in
response to
fluid intake
• Methods
– Refractometer
– Reagent strips
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-31
Chemical Testing of Urine Specimens
• Check label on
specimen
• Determine the status
of
– Carbohydrate
metabolism
– Liver or kidney
function
– Acid-base balance
– Presence of drugs,
toxins, or infections
• Reagent strip testing
– Changes indicate
presence of
concentration of a
substance
– Follow instructions
carefully
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-32
Chemical Testing of Urine Specimens
(cont.)
• Ketone bodies
– Normally none in
urine
– Presence
• Patient on a lowcarbohydrate diet
• Starvation
• Excessive vomiting
• Diabetes mellitus
• pH
– Normal 5.0 to 8.0
– Alkaline
• UTI
• Metabolic/
respiratory
alkalosis
– Acidic
• Phenylketonuria
• Acidosis
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-33
Chemical Testing of Urine Specimens
(cont.)
• Blood
– Hematuria
• Menstruation
• Infection
• Trauma
– Hemoglobinuria –
free
hemoglobin in urine
– Myoglobinuria
• Myoglobin in urine
• Injured or damaged
muscles
• Bilirubin
– From the breakdown
of hemoglobin
– Bilirubinuria – early
sign of liver disease
• Urobilinogen
– Elevated – increased
RBC destruction
– Lacking – bile duct
obstruction
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-34
Chemical Testing of Urine Specimens
(cont.)
• Glucose
– Normally in small amounts
– Glycosuria – diabetes
• Protein
– Excess – renal disease
– Proteinuria – common in pregnancy and after
heavy exercise
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-35
Chemical Testing of Urine Specimens
(cont.)
• Nitrite – suggests
bacterial infection
• Leukocytes –
urinary tract or
renal infection
• Phenylketones
– Presence indicates
phenylketonuria
(PKU) – genetic
disorder
– Blood testing is
more routine for
newborns
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-36
Chemical Testing of Urine Specimens
(cont.)
• Pregnancy test
– Detect human chorionic gonadotropin (HCG)
• Peak at 8 weeks
• Quick, easy to perform and interpret
– Enzyme immunoassay (EIA)
• Newer technology
• Antigen/antibody reaction
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-37
Chemical Testing of Urine Specimens
(cont.)
• Presence of STDs
– Screening for chlamydia – 15- to 25-year-old
sexually active females
– Nucleic acid amplification tests (NAATs)
•
•
•
•
Detect nucleic acid in urine
Chlamydia and gonorrhea
Advantage – highly specific, non-invasive
Disadvantage – expensive, no organism remains
for culture
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-38
Microscopic Examination of Urine
Specimens
• View elements only visible with
microscope
• Centrifuge
– Obtain sediment
– Spins fluid – heavier substances settle to the
bottom of the tubes
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-39
Microscopic Examination of Urine
Specimens (cont.)
• Cells
– Epithelial cells
– White blood cells
– Red blood cells
• Casts
– Cylindrical
elements
– Types
•
•
•
•
•
•
Hyaline
Granular
RBC casts
WBC casts
Epithelial cell casts
Waxy
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-40
Microscopic Examination of Urine
Specimens (cont.)
• Crystals
• Yeast cells
– Naturally produced
solids of definite
form
– May be confused
with RBCs
– Common in urine
– Associated with
genitourinary
tract infection,
diabetes
– Determine pH
before testing
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-41
Microscopic Examination of Urine
Specimens (cont.)
• Bacteria
– A few are normal
– Infection if urine
also has
• Putrid odor
• WBCs
• Parasites
– Infection or
contamination
– Trichomonas
vaginalis – most
common
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-42
Apply Your Knowledge
1.
What is the specific gravity shown on this
refractometer screen?
ANSWER: The specific
gravity shown here is
1.030.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-43
Apply Your Knowledge
2. A urinalysis
has detected that a patient
has protein in his urine. Why is this
important?
ANSWER: Protein in the urine usually indicates
renal disease.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-44
In Summary
16.1 Urine is formed during a filtration process that occurs
in the nephron. It is made up of 95% water and 5%
waste products and other dissolved chemicals,
including urea, uric acid, ammonia, calcium,
creatinine, sodium, chloride, potassium, sulfates,
phosphates, bicarbonates, hydrogen ions, urochrome,
urobilinogen, a few red blood cells, and a few white
blood cells.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-45
In Summary (cont.)
16.2 Instructions for obtaining specific types of specimens
will vary according to the test. The general
instructions for urine specimen collection are: urinate
into the container indicated by the laboratory; if the
collection container contains liquid or powdered
preservative, do not pour it out; always refrigerate the
labeled collection container or keep it in a cooler or
pail filled with ice; be sure to keep the lid on the
container.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-46
In Summary (cont.)
16.3 The general guidelines for collecting a urine specimen
include: follow the procedure that is specified for the
urine test that will be performed; use the type of
specimen container indicated by the laboratory;
properly label the specimen container; explain the
procedure to the patient when assisting in the
collection process; wash your hands before and after
the procedure and wear gloves during the procedure;
and complete all necessary paperwork.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-47
In Summary (cont.)
16.4 Several types of urine specimens are collected in the
medical office. Each specimen has a slightly different
collection method. The various specimens include
random, first morning, clean-catch midstream, timed,
and 24-hour.
16.5 Urinary catheterization involves inserting a plastic
drainage tube into the kidney, the ureter, or the
bladder.
16.6 When the medical assistant obtains a urine specimen
from a patient or takes a history of a patient who may
have a urinary problem, she or he needs to consider
the patient’s sex, condition, and age.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-48
In Summary (cont.)
16.7 When collecting a chain-of-custody specimen, the
following safeguards should be used: positively
identify the donor; have the donor remove outer
clothing and empty pockets, displaying all items; add
bluing agent to the water in the toilet and turn off
other water sources; remain by the door while the
specimen is being obtained; measure and record the
temperature of the specimen within four minutes;
have the donor witness the specimen transfer;
complete additional information on the form; sign the
CCF; give a copy of the CCF to the donor; place the
specimen in a leak-proof bag with a copy of the form;
and release the specimen to the courier service.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-49
In Summary (cont.)
16.8 Proper preservation and storage of specimens are
essential. A specimen should not be left unpreserved
for more than 1 hour. Refrigerate a specimen if it
cannot be tested within an hour. Bring the specimen
back to room temperature before testing.
16.9 Urinalysis is the evaluation of urine by various types
of testing methods to obtain information about body
health and disease.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-50
In Summary (cont.)
16.10 The physical characteristics of normal urine include
color and turbidity, volume, odor, and specific gravity.
16.11 The chemicals that may be found in urine specimens
include ketones, nitrite, bilirubin, glucose, and
protein.
16.12 During microscopic urine examination, elements that
are categorized and counted include the cells, casts,
crystals, yeast, bacteria, and parasites.
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.
16-51
End of Chapter 16
A human being: an
ingenious assembly of
portable plumbing.
~ Christopher Morley,
1890-1957
© 2011 The McGraw-Hill Companies, Inc. All rights reserved.