chapter © 2011 the mcgraw-hill companies, inc. all rights reserved. 47 collecting, processing, and...

CHAPTER

© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

47Collecting,

Processing, and Testing Urine Specimens


47-2

Learning Outcomes47.1 Describe the characteristics of urine, including

its formation, physical composition, and chemical properties.

47.2 Explain how to instruct patients in specimen collection.

47.3 Identify guidelines to follow when collecting urine specimens.

47.4 Describe proper procedures for collecting various urine specimens.


47-3

Learning Outcomes (cont.)

47.5 Explain the process of urinary catheterization.

47.6 List special considerations that may require you to alter guidelines when collecting urine specimens.

47.7 Explain how to maintain the chain of custody when processing urine specimens.

47.8 Explain how to preserve and store urine specimens.


47-4

Learning Outcomes (cont.)

47.9 Describe the process of urinalysis and its purpose.

47.10Identify the physical characteristics present in normal urine specimens.

47.11Identify the chemicals that may be found in urine specimens.

47.12Identify the elements categorized and counted as a result of microscopic examination of urine specimens.


47-5

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


47-6

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


47-7

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


47-8

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


47-9

Formation of Urine• Nephron

– Functional unit of the kidney

– Removes end products of metabolism

– Allows for reabsorption of water and electrolytes

– Maintains normal fluid balance

• Processes in urine formation

– Glomerular filtration

– Tubular reabsorption

– Tubular secretion


47-10

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


47-11

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 includeA. urea, uric acid, and ammonia.B. chloride, potassium, and sugar.C. red blood cells, sperm, and H2O2

D. hydrogen ions, urochrome, and uranium.

ANSWER:


47-12

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


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Specimen Types

• Quantitative analysis – measuresamount of a specific substance in the urine

• Qualitative analysis – simplydetermines if a substance ispresent in the urine

• Types vary in the method used to collect a specimen and in the time frame in which to collect a specimen


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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


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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


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Catheterization

• Urinary catheter – a plastic tube inserted to provide urinary drainage

• Catheterization – procedure by which the catheter is inserted


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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


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• 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


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• Not a routine procedure due to risk of infection

• Not typically performed by medical assistants– Check scope of practice– Assemble supplies –

catheterization kits


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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


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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?


47-22

Establishing Chain of Custody

• Do not alter established procedure

• Positively identify patient

• Explain procedure and have patient sign a consent form

• Examine specimen and check temperature

• Complete documentation


47-23

Preservation and Storage

• Chemical, physical, and microscopic changes occur if urine is left at room temperature for more than 1 hour

• Preservation– Refrigeration

• Prevents growth for 24 hours• Return to room temperature before testing

– Chemical preservatives

Specimens only


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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!


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Urinalysis

• Evaluation of urine to obtain information about body health and disease

• Types of testing– Physical– Chemical– Microscopic


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Urinalysis (cont.)

• Values – Negative or none, normal,

or a range of concentration

– Within normal limits indicate health and normality

– Screening test – must havefollow-up testing


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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


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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


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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


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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


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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


47-32

Chemical Testing of Urine Specimens (cont.)

• Ketone bodies – Normally none in

urine– Presence

• Patient on a low-carbohydrate diet

• Starvation• Excessive vomiting• Diabetes mellitus

• pH– Normal 5.0 to 8.0– Alkaline

• UTI• Metabolic/

respiratory alkalosis

– Acidic • Phenylketonuria• Acidosis


47-33


• 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


47-34


• Glucose– Normally in small amounts– Glycosuria – diabetes

• Protein– Excess – renal disease – Proteinuria – common in pregnancy and after

heavy exercise


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• Nitrite – suggests bacterial infection

• Leukocytes – urinary tract or renal infection

• Phenylketones– Presence indicates

phenylketonuria (PKU) – genetic disorder

– Blood testing is more routine for newborns


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• 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


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• 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


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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


47-39

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


47-40


• Crystals – Naturally produced

solids of definite form

– Common in urine

– Determine pH before testing

• Yeast cells– May be confused

with RBCs

– Associated with genitourinary tract infection, diabetes


47-41


• Bacteria – A few are normal

– Infection if urine also has

• Putrid odor• WBCs

• Parasites– Infection or

contamination

– Trichomonas vaginalis – most common


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1. What is the specific gravity shown on this refractometer screen?

ANSWER: The specific gravity shown here is 1.030.


47-43


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.


47-44

In Summary

47.1 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.


47-45

In Summary (cont.)

47.2 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.


47-46

In Summary (cont.)

47.3 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.


47-47

In Summary (cont.)

47.4 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.

47.5 Urinary catheterization involves inserting a plastic drainage tube into the kidney, the ureter, or the bladder.

47.6 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.


47-48

In Summary (cont.)

47.7 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.


47-49

In Summary (cont.)

47.8 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.

47.9 Urinalysis is the evaluation of urine by various types of testing methods to obtain information about body health and disease.


47-50

In Summary (cont.)

47.10 The physical characteristics of normal urine include color and turbidity, volume, odor, and specific gravity.

47.11 The chemicals that may be found in urine specimens include ketones, nitrite, bilirubin, glucose, and protein.

47.12 During microscopic urine examination, elements that are categorized and counted include the cells, casts, crystals, yeast, bacteria, and parasites.


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End of Chapter 47

A human being: an ingenious assembly of portable plumbing.

~ Christopher Morley, 1890-1957

chapter © 2011 the mcgraw-hill companies, inc. all rights reserved. 47 collecting, processing, and...

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