Review Cards - Urinalysis & Body Fluids Flashcards
Urine specimens - random - use
routine urinalysis
Urine specimens - random - collection
Any time
Urine specimens - random - not ideal?
Because urine may be dilute & contaminated
Urine specimens - first morning - use
Routine urinalysis
Urine specimens - first morning - collection
Upon waking
Urine specimens - 2-hour postprandial - use
Diabetes mellitus monitoring
Urine specimens - 2-hour postprandial - collection
2 hours after eating
Urine specimens - 2-hour postprandial - best for detecting?
glycosuria
Urine specimens - 24-hour - use
quantitative chemical tests
Urine specimens - 24-hour - collection
-discard 1st void on day 1 & note time
-collect all urine for next 24 hours, including 1st void at same time on day 2
Urine specimens - 24-hour - common source of error
improper collection
Urine specimens - clean catch - use
routine, culture
Urine specimens - clean catch - collection
cleanse external genitalia & collect midstream in sterile container
Urine specimens - catheterized - use
culture
Urine specimens - catheterized - collection
catheter inserted into urethra
Urine specimens - suprapubic aspiration - use
culture
Urine specimens - suprapubic aspiration - collection
needle inserted through abdomen into bladder
Urine volume - normal daily volume
600-2,000 mL (average 1,200-1,500 mL)
Urine volume - normal day-to-night ratio
2:1 - 3:1
Urine volume - diuresis
increased urine production
Urine volume - polyuria
Marked increase in urine flow
-adult: >2,500 mL/day
-children: 2.5-3 mL/kg/day
Urine volume - oliguria
Marked decrease in urine flow
-adult: <400 mL/day
-children: <0.5 mL/kg/hour
-infants: <1 mL/kg/hour
Urine volume - anuria
no urine production
Urine color - normal
yellow due to urochrome
Urine color - diluted urine
colorless, pale yellow
Urine color - concentrated urine
dark yellow, amber
Urine color - bilirubin
amber, orange, yellow-green; yellow foam on shaking
Urine color - urobilin
amber, orange; NO yellow foam in shaking
Urine color - homogentisic acid
normal on voiding; brown or black on standing
Urine color - melanin
brown or black on standing
Urine color - methemoglobin
brown or black
Urine color - myoglobin
red; brown on standing
Urine color - blood/hemoglobin
pink or red when fresh; brown on standing
Urine color - porphyrin
port-wine
Urine color - drugs, medications, food
green, blue, red, orange
Urine color - Pseudomonas infection
green, blue-green
Changes in unpreserved urine at room temperature >2 hours - turbidity
increased
-cause:
—multiplication of bacteria
—precipitation of amorphous crystals
Changes in unpreserved urine at room temperature >2 hours - pH
increased
-cause: conversion of urea to ammonia by bacteria
Changes in unpreserved urine at room temperature >2 hours - glucose
decreased
-cause: metabolism by bacteria
Changes in unpreserved urine at room temperature >2 hours - ketones
decreased
-cause:
—volatilization of acetone
—breakdown of acetoacetate by bacteria
Changes in unpreserved urine at room temperature >2 hours - urobilinogen
decreased
-cause: oxidation to urobilin
Changes in unpreserved urine at room temperature >2 hours - bilirubin
decreased
-cause: oxidation to biliverdin
Changes in unpreserved urine at room temperature >2 hours - WBCs, RBCs, casts
decreased
-cause: lysis in dilute or alkaline urine
Chemical urinalysis by reagent strip - pH - normal
First AM: 5-6
Random: 4.5-8
Chemical urinalysis by reagent strip - pH - principle
double indicator system
Chemical urinalysis by reagent strip - pH - significance
-acid-base balance
-management of UTI/renal calculi
Chemical urinalysis by reagent strip - pH - acid
protein/meat diet
Chemical urinalysis by reagent strip - pH - alkaline
vegetarian diet
Chemical urinalysis by reagent strip - pH - pH 9
Improperly preserved specimen
Chemical urinalysis by reagent strip - protein - normal
negative - trace
Chemical urinalysis by reagent strip - protein - principle
protein error of indicators
Chemical urinalysis by reagent strip - protein - significance
possible renal disease
Chemical urinalysis by reagent strip - protein - buffered to a pH of?
3
Chemical urinalysis by reagent strip - protein - most sensitive to?
albumin
Chemical urinalysis by reagent strip - protein - orthostatic proteinuria
-benign condition
-protein is negative in 1st AM specimen
-protein is positive after standing
Chemical urinalysis by reagent strip - glucose - normal
Negative
Chemical urinalysis by reagent strip - glucose - principle
glucose oxidase/peroxidase
Chemical urinalysis by reagent strip - glucose - significance
possible diabetes mellitus
Chemical urinalysis by reagent strip - glucose - specific for?
glucose
Chemical urinalysis by reagent strip - glucose - normal renal threshold
160-180 mg/dL
Chemical urinalysis by reagent strip - ketones - normal
negative
Chemical urinalysis by reagent strip - ketones - principle
sodium nitroprusside reaction
Chemical urinalysis by reagent strip - ketones - significance
Increased fat metabolism:
-uncontrolled diabetes mellitus
-vomiting
-starvation
-low carb diet
-strenuous exercise
Chemical urinalysis by reagent strip - ketones - most sensitive to?
Acetoacetic acid
Chemical urinalysis by reagent strip - ketones - less sensitive to?
acetone
Chemical urinalysis by reagent strip - ketones - doesn’t react with?
beta-hydroxybutyric acid
Chemical urinalysis by reagent strip - blood - normal
negative
Chemical urinalysis by reagent strip - blood - principle
pseudoperoxidase activity of hemoglobin
Chemical urinalysis by reagent strip - blood - significance
-hematuria
-hemoglobinuria
-myoglobinuria
Chemical urinalysis by reagent strip - blood - uniform color vs. speckled
-uniform color: HGB or myoglobin
-speckled: RBCs
Chemical urinalysis by reagent strip - blood - bilirubin - normal
negative
Chemical urinalysis by reagent strip - blood - bilirubin - principle
Diazo reaction
Chemical urinalysis by reagent strip - blood - bilirubin - significance
-liver disease
-biliary obstruction
Chemical urinalysis by reagent strip - blood - bilirubin - what type excreted in urine?
conjugated bilirubin
Chemical urinalysis by reagent strip - blood - urobilinogen - normal
1 Ehrlich Unit or 1 mg/dL
Chemical urinalysis by reagent strip - blood - urobilinogen - principle
Ehrlich aldehyde reaction or diazo reaction
Chemical urinalysis by reagent strip - blood - urobilinogen - significance
-liver disease
-hemolytic disorders
Chemical urinalysis by reagent strip - blood - urobilinogen - reagent strips DO NOT detect?
they do not detect ABSENCE of urobilinogen, only increased
Chemical urinalysis by reagent strip - blood - nitrite - normal
negative
Chemical urinalysis by reagent strip - blood - nitrite - principle
Greiss reaction
Chemical urinalysis by reagent strip - blood - nitrite - significance
UTI
Chemical urinalysis by reagent strip - blood - nitrite - bacteria
some bacteria reduce nitrates to nitrites
Chemical urinalysis by reagent strip - blood - nitrite - increased sensitivity when?
Urine in bladder at least 4 hours
Chemical urinalysis by reagent strip - blood - leukocyte esterase - normal
negative
Chemical urinalysis by reagent strip - blood - leukocyte esterase - principle
LE reaction
Chemical urinalysis by reagent strip - blood - leukocyte esterase - significance
UTI
Chemical urinalysis by reagent strip - blood - leukocyte esterase - longest reaction time
2 minutes
Chemical urinalysis by reagent strip - blood - leukocyte esterase - detects
intact & lysed granulocytes and monocytes
Chemical urinalysis by reagent strip - blood - leukocyte esterase - does NOT detect?
lymphocytes
Chemical urinalysis by reagent strip - blood - specific gravity - normal
Random specimen: 1.003-1.030
Chemical urinalysis by reagent strip - blood - specific gravity - principle
pKa change of polyelectrolyte
Chemical urinalysis by reagent strip - blood - specific gravity - significance
Indication of kidney’s concentrating ability & state of hydration
-increased: DM due to glucose
-decreased: diabetes insipidus due to decreased ADH
Chemical urinalysis by reagent strip - blood - specific gravity - only measures?
ionic solute
Chemical urinalysis by reagent strip - blood - specific gravity - not affected by?
-urea
-glucose
-radiographic contrast media
-plasma expanders
General sources of error with reagent strip testing: failure to test within 2 hours of collection or to preserve correctly - possible effect?
changes in chemical composition
General sources of error with reagent strip testing: failure to bring refrigerated specimens to room temperature before testing - possible effect?
False negative enzymatic reactions
General sources of error with reagent strip testing: failure to mix specimen well- possible effect?
False negative leukocyte/blood
-WBCs, RBCs settle out
General sources of error with reagent strip testing: failure to perform quality control - possible effect?
Erroneous results
-perform pos & neg control every 24 hours & when opening new container
General sources of error with reagent strip testing: failure to dip all test pads in urine - possible effect?
False negative reactions
General sources of error with reagent strip testing: prolonged dipping - possible effect?
False negative reactions
-reagents may leach from pads
General sources of error with reagent strip testing: failure to remove excess urine from strip - possible effect?
run over of chemicals to adjacent pads, distortion of colors
General sources of error with reagent strip testing: highly pigmented urine - possible effect?
atypical colors, false positive reactions
-pigment masks true reactions
-test by alternate method
General sources of error with reagent strip testing: failure to read at recommended time - possible effect?
erroneous results
General sources of error with reagent strip testing: failure to store strips properly - possible effect?
erroneous results
-store in capped original container at RT
Specific sources of error with reagent strip testing - pH - increased or false positive
improperly preserved specimen
Specific sources of error with reagent strip testing - pH - decreased or false negative
acid run over from protein square
Specific sources of error with reagent strip testing - protein - increased or false positive
-highly buffered alkaline urine
-prolonged dipping
-contaminated container
-increased specific gravity
Specific sources of error with reagent strip testing - protein - decreased or false negative
proteins other than albumin
Specific sources of error with reagent strip testing - glucose - increased or false positive
contamination with peroxide or bleach
Specific sources of error with reagent strip testing - glucose - decreased or false negative
-unpreserved specimen
-increased ascorbic acid
-increased specific gravity
-decreased temperature
Specific sources of error with reagent strip testing - ketones - increased or false positive
-red pigments
-dyes
-some meds
Specific sources of error with reagent strip testing - ketones - decreased or false negative
-improper storage:
—acetone is volatile
—bacteria break down acetoacetic acid
Specific sources of error with reagent strip testing - blood - increased or false positive
-menstruation
-oxidizing agents
-bacterial peroxidase
Specific sources of error with reagent strip testing - blood - decreased or false negative
-increased ascorbic acid
-increased nitrite
-increased specific gravity (crenated RBCs)
-unmixed specimen
Specific sources of error with reagent strip testing - bilirubin - increased or false positive
highly pigmented urine
Specific sources of error with reagent strip testing - bilirubin - decreased or false negative
-exposure to light
-increased ascorbic acid
-increased nitrite
Specific sources of error with reagent strip testing - urobilinogen - increased or false positive
highly pigmented urine
Specific sources of error with reagent strip testing - urobilinogen - decreased or false negative
-improperly preserved specimen (oxidation to urobilin)
-formalin
Specific sources of error with reagent strip testing - nitrite - increased or false positive
-highly pigmented urine
-improperly preserved specimen (contaminating bacteria produce nitrites)
Specific sources of error with reagent strip testing - nitrite - decreased or false negative
-non-nitrate-reducing bacteria
-inadequate time in bladder
-reduction of nitrites to N2
-decreased dietary nitrate
-antibiotics
-increased ascorbic acid
-increased specific gravity
Specific sources of error with reagent strip testing - LE - increased or false positive
-highly pigmented urine
-oxidizing agents
-formalin
-nitrofurantoin
-vaginal discharge
Specific sources of error with reagent strip testing - LE - decreased or false negative
-increased glucose
-increased protein
-increased ascorbic acid
-increased specific gravity
-antibiotics
-reading too soon
Specific sources of error with reagent strip testing - SG - increased or false positive
increased protein
Specific sources of error with reagent strip testing - SG - decreased or false negative
-alkaline urine (add 0.005 if pH is 6.5 or higher; correction is made by automated readers)
Other urine chemistry tests - microalbumin - detects
albumin in low/moderate concentrations
Other urine chemistry tests - microalbumin - method(s)
-immunoassay on 24-hour urine
-albumin-to-creatinine ratio (ACR) on random sample
-dipsticks available for ACR
Other urine chemistry tests - microalbumin - not detected by?
most urine dipsticks
Other urine chemistry tests - microalbumin - concentration predictive of diabetic nephropathy
Males:
50-200 mg/24 hour OR
ACR >=2.8
Females:
50-200 mg/24 hour OR
ACR >=2.0
Other urine chemistry tests - Ictotest - detects
bilirubin
Other urine chemistry tests - Ictotest - method(s)
Diazo reagent
Other urine chemistry tests - Ictotest - sources of error - false positives
urine pigments
Other urine chemistry tests - Ictotest - sources of error - false negatives
-exposure to light
-improperly stored specimen
-increased ascorbic acid
-increased nitrite
Other urine chemistry tests - Ictotest - less affected by?
interfering substances
Sediment stains - Sternheimer-Malbin - action
delineates cell structure and contrasting colors of nucleus vs. cytoplasm
Sediment stains - Sternheimer-Malbin - function
identify WBCs, epithelial cells, and casts
Sediment stains - Oil Red O and Sudan III - action
stains triglycerides and neutral fats, cholesterol will not stain
Sediment stains - Oil Red O and Sudan III - function
ID free fat droplets and lipid-containing cells or casts
Sediment stains - Hansel stain - action
methylene blue and eosin Y stain eosinophilic granules
Sediment stains - Hansel stain - function
ID eosinophils in the urine
Epithelial cells in the urine sediment - squamous epithelial cell - description
-40-50 um
-flat
-prominent round nucleus
Epithelial cells in the urine sediment - squamous epithelial cell - origin
-lower urethra
-vagina
Epithelial cells in the urine sediment - squamous epithelial cell - clinical significance
usually none
Epithelial cells in the urine sediment - squamous epithelial cell - increased numbers usually seen from?
females
Epithelial cells in the urine sediment - squamous epithelial cell - may obscure?
RBCs & WBCs
Epithelial cells in the urine sediment - squamous epithelial cell - reduced by?
collecting midstream clean-catch specimen
Epithelial cells in the urine sediment - transitional epithelial cell - description
-20-30 um
-spherical, pear-shaped, or polyhedral
-round central nucleus
Epithelial cells in the urine sediment - transitional epithelial cell - origin
-renal pelvis
-ureters
-bladder
-upper urethra
Epithelial cells in the urine sediment - transitional epithelial cell - clinical significance
seldom significant
Epithelial cells in the urine sediment - transitional epithelial cell - may form?
syncytia (clumps)
Epithelial cells in the urine sediment - renal tubular epithelial cell - description
-slightly larger than a WBC (12 um)
-round
-eccentric round nucleus
Epithelial cells in the urine sediment - renal tubular epithelial cell - origin
renal tubules
Epithelial cells in the urine sediment - renal tubular epithelial cell - clinical significance
-tubular necrosis
-toxins
-viral infections
-renal rejection
Epithelial cells in the urine sediment - renal tubular epithelial cell - must differentiate from?
WBCs
Epithelial cells in the urine sediment - oval fat body - description
renal tubular epithelial cell containing fat droplets
Epithelial cells in the urine sediment - oval fat body - origin
renal tubules
Epithelial cells in the urine sediment - oval fat body - clinical significance
-tubular necrosis
-toxins
-viral infections
-renal rejection
Epithelial cells in the urine sediment - oval fat body - polarized light
Maltese crosses
Blood cells in the urine sediment - WBCs - description
-usually polys
-about 12 um
-granular appearance
Blood cells in the urine sediment - WBCs - origin
kidney, bladder, or urethra
Blood cells in the urine sediment - WBCs - clinical significance
-cystitis
-pyelonephritis
-tumors
-renal calculi
Blood cells in the urine sediment - WBCs - normal
0-8/HPF
Blood cells in the urine sediment - WBCs - clumps
associated with acute infection
Blood cells in the urine sediment - glitter cell - description
-WBC with Brownian movement of granules
-stain faintly or not at all
Blood cells in the urine sediment - glitter cell - description
-WBC with Brownian movement of granules
-stain faintly or not at all
Blood cells in the urine sediment - glitter cell - origin
kidney, bladder, or urethra
Blood cells in the urine sediment - glitter cell - clinical significance
-cystitis
-pyelonephritis
-tumors
-renal calculi
Blood cells in the urine sediment - glitter cell - observed in?
hypotonic urine
Blood cells in the urine sediment - RBC - description
-biconcave disk
-about 7 um
-smooth
-non-nucleated
Blood cells in the urine sediment - RBC - origin
kidney, bladder, or urethra
Blood cells in the urine sediment - RBC - clinical significance
-infection
-trauma
-tumors
-renal calculi
-dysmorphic RBCs indicate glomerular bleeding
Blood cells in the urine sediment - RBC - normal
0-3/HPF
Blood cells in the urine sediment - RBC - hypertonic urine
crenated RBCs
Blood cells in the urine sediment - RBC - hypotonic urine
RBCs lyse
Blood cells in the urine sediment - RBC - 2% acetic acid
RBCs lyse
Normal crystals found in acid or neutral urine - amorphous urates - description
irregular granules
Normal crystals found in acid or neutral urine - amorphous urates - precipitate
pink
Normal crystals found in acid or neutral urine - amorphous urates - may obscure?
significant sediment