Urinalysis Flashcards
(40 cards)
Eight Preservatives
Freezing Toluene Thymol Chlorine Formaldehyde Hydrogen Chloride Boric Acid Preservative Tablets
Clinical reasons for performing urinalysis testing
- Important indicator of health
- Screening to detect and assess:
- Renal function/disorder
- Endocrine or Metabolic function/disorder
- UTI
- Systemic Diseases - Cost effective in-vitro diagnostic test
- Non-invasive
- Simple to perform
Two Methods of Urine Collection
Non-instrumented
Instrumented
4 Non-instrumented methods of urine collection
First-morning void
Random urine
Clean catch
24-hr urine collection
3 Instrumented urine collection
Urethral
Suprapubic
Catheterization and bladder irrigation
Preferably urine specimens are tested fresh, within how many hours?
1-2 hours
Specimens need to be refrigerated, if not tested immediately, within how many hours?
3-6 hours
Urine decomposition (3 main themes)
- Decomposition due to bacteria.
- Urea splitting bacteria producing ammonia which binds with hydrogen to increase urine PH.
- Other changes:
- increased PH will dissolve any casts present
- if glucose is present, bacteria may use glucose for fuel and produce a false negative glycosuria
- urinary elements like casts and blood will deteriorate
Chemical preservatives allow what?
Transport from home to lab
Transport across the country
Advantages and disadvantages for different types of preservatives
What must be done when preservatives are used?
Label the specimens as such
Freezing
Pro: For specimen transport
Con: May destroy formed elements
Toluene
Pro: - acetone - diacetic acid - and proteins ..by floating on top (airtight seal)
Con:
- flammable
- difficult to separate from specimen
Thymol
Pro: Inhibits bacteria and fungus
Con: False positive for protein
Chloroform
Pro: urine aldosterone levels
Con: settles to the bottom
Formaldehyde
Pro: urinary sediment/cells
Con: interferes with glucose elevation
Hydrogen Chloride
Pro: stabilizes steroids
Con:
- hazardous liquid and fumes
- formed elements are destroyed
Boric Acid
Pro: chemical and formed elements
Con: uric acid may precipitate
Preservation Tablet
Pro:
- preserves for dipstick chem. analysis and sediment eval.
Con:
- unsuitable for sodium, potassium and hormone analysis
First-morning void
Most concentrated
Increase number of abnormal elements
Decreased deterioration of formed elements
Desired specimen for chemical and micro exam
Random urine
Collected anytime
Most convenient and common
Can detect abnormalities but not as sensitive as 1st morning void
Clean Catch
Choice for bacterial cultures
-perform tests within 12hrs, as long as its refrigerated
24-hr urine specimen
Gives quant results
Preservatives may be needed
Urethral catheterization
- not recommended for bacteriologic exams
- use if no other way possible
- obese PTs with difficult sample collection
Suprapubic needle aspiration
- choice for infants and young children
- used to confirm (+) culture and before start of therapy
