ch 7 Flashcards
recommended volume to centrifuge urine
400-450 g
supravital staining
crystal-violent and safranin (sternheimer-malbin)
–> enhances visualization
acetic acid staining
brings out nuclear detail of WBCs and lyses RBCs
–> visualizes WBS
fat stains
sudan III or oil red O
–> identify fats inside cells or free floating
gram stain
identifies bacteria and yeast (not used for urinalysis
prussian blue stain
stains iron in hemosiderin granules blue
hansel stain
methylene blue and eosin-Y
–> identifies eosinophils
microscopy techniques
brightfield, phase contrast, polarizing, interference contrast
brightfield microscopy
most commonly used (black and white)
phase contrast
ideal for urine sediments as it allows for more detailed visualization of translucent components and living cells
polarizing
confirms presence of cholesterol
–> used on crystals
interference contrast
three dimensional images, but high cost prevents use by most laboratories
formed elements
not all formed elements are abnormal
–> large amounts is diagnostically significant
RBCs
biconcave disks
–> normal RBC is less than 3 per hpf
increased RBC can mean
with casts: renal bleeding
no casts: bleeding below kidney