Urinalysis Flashcards
What are the types of specimen?
- Random
- First Morning
- Timed
- 24 hours
How can urine be collected?
- Clean catch
- Catheter
- Suprapubic
What are some preservatives for urine?
- Boric acid
- HCL
- Chlorhexidine
- Formalin
How much sample do you need for testing?
Minimum 12 mL
preferably 50 mL
What is the preferred sample for chemical analysis?
First morning
What is the most common sample collected?
Random
What are not acceptable samples?
- Fecal contam
- Bathroom tissue
- Foreign materials
What changes can occur is urine stands at room temp for longer than 2 hours?
- deterioration of formed elements
- Bilirubin and urobilinogen are unstable
- pH change
- Bacteria incubation
- Lysis
How should urine samples be transported?
Refrigerated and with a sub culture on agar
What does QC check for ?
- Checks the strip
- Checks the analyzer
- Checks the technique
How often should QC be ran?
2 levels every 24 hours
How much urine does one produce a day?
600 - 1,500 mL / day
What are the physical characteristics of urine are examined?
- Colour
- Clarity
- Amount
What determines concentration of urine?
Specific gravity and osmolarity
What is specific gravity?
concentration and diluting ability of the kidneys
- affected by glucose and proteins
What are the different diabetes?
Mellitus: deficient in insulin
Insipidus: deficient in ADH
What is osmolarity?
Concentrating and diluting ability of the kidneys
- costly
- better than specific gravity
What does glycosuria/ glucosuria mean?
significant amount of glucose in urine
What does Hematuria mean?
presence of blood or intact RBC in urine
What does hemoglobinuria mean?
presence of free hemoglobin in the urine caused by intravascular hemolysis
What does myoglobinuria mean?
myoglobin in the heme protein of striated muscles present in urine.
What is the freezing point depression?
measurement based on how long it takes urine to freeze
*when more substance is there the longer it may take to freeze .
What is reflectance spectrophotometry used in urinalysis?
Light is shined on the urine pad and the reflectance of the light is measured.
What does polyuria mean?
more than normal urine output
What does anuria mean?
Absence of urine
What does oliguria mean?
Excretion less than 500 mL of urine.
What is the name of the slide used for urine microscopy?
Deci slides
What determines if urine is microscopically examined?
presence of
- Proteins
- RBC
- WBC
- Nitrites
What happens when there too much urine on test strip?
run over effect
What is the average pH of urine?
6
What protein is the reagent test strip sensitive for?
Albumin
What can cause protein false pos’s?
Alkaline pH
Dipping too long
Cleaners
What can cause protein false neg’s?
Diluted urine
proteins other than albumin
What is the threshold for glucose?
10 mmol/L
What are false pos’s for glucose?
Cleaning agents
urobilinogen
What can cause false neg’s for glucose?
Temp (cold)
Vit.C
High ketones
How are ketones formed?
during the catabolism of fatty acids
What are false pos’s for ketones?
drugs
high specific gravity + low pH
Highly pigmented urines
What are false neg’s for ketones?
any ketone produced that isn’t acetone
What are the three ketones?
- Acetone
- Diacetic acid
- B- hydroxybutyrate
Which ketone is tested for?
Acetone
What are false pos’s for occult blood?
Bleach
high bac content
betadine
What are false neg’s for occult blood?
failure to mix sample
Vit.C
formalin
How are bilirubin and urobilinogen produced?
breakdown of hemoglobin
What happens when bilirubin is exposed to light?
oxidizes greens biliverdin
What are false pos’s for bilirubin?
- waiting too long to read
- drugs
- metabolites
What are false neg’s for bilirubin?
Vit. C
elevated nitrites
light
room temp too long
What are false pos’s for urobilinogen?
high bilirubin
What are false neg’s for urobilinogen?
high nitrite
formalin
improper storage
What produce nitrites?
- Ecoli
- Enterobacters
- Klebsiella
(organisms that cause UTI)
What are false pos’s for nitrites?
allowing urine to stand
red urine
What are false neg’s for nitrites?
Vit.C
high specific gravity
high urobilinogen
Which leukocyte is the most common for leukocyte esterase results?
Neutrophils
What are false pos’s for leukocyte esterase?
detergents
vaginal discharge
preservatives
What are false neg’s for leukocyte esterase?
high specific gravity
urine with glucose and proteins
drugs
