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Flashcards in Microscopic Urine Examination Deck (48)
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1

ideal specimen

first morning
most concentrated & acidic

2

preparation of sediment

10-15 ml of well mixed urine less than 2 hr old
slow centrifuge
decant supernatant
one drop of sediment to slide w/ coverslip
examine

3

Sediment stains

supravital - sternheimer-Malbin
acetic acid - lyses RBC
fat stains
gram stain
prussian blue
hansel stain

4

Microscopes

brightfield- most common
phase-contrast
polarizing: confirms cholesterol & crystals
interference contrast: 3D images

5

tips for microscopic examination of urine on brightfield

lower condenser
close iris
initially view 10x for casts
40x for rest of elements

6

epithelial cells

originate from any site within UT
indicative of infection/inflammation or contamination

7

squamous epithelial cells

large, flat cells with abundant cytoplasm
from vagina or lower portion of male urethra
indicative of vaginal contamination in female urine

8

Transitional (urothelial) epithelial cells

originate in blader, ureters, renal pelvis, renal calyces & upper urethra (males)
small, less cytoplasm; round or pear shaped
large numbers are indicative of bladder carcinoma
random urine is best
'poached egg' appearance

9

renal tubular epithelial cells

found in tubules of nephron
slightly larger than WBC; round eccentric nucleus w/ scant cytoplasm
indicative of tubular necrosis
stain can be helpful
'hard boiled cut in half'

10

oval fat bodies

lipid containing RTEs, highly refractile
usually seen with free floating fat droplets
occur when lipids pass across the glomerular membrane & are absorbed by the RTEs

11

RBCs

pale, smooth, biconcave small circles
sources of confusion: WBC, yeast, bubbles & oil droplets

12

hypotonic urine & RBCs

low specific gravity
swollen RBC

13

hypertonic urine & RBCs

high specific gravity
crenated RBCs

14

dysmorphic RBCs

glomerular origin

15

increased RBCs

along with RBC casts - renal bleeding
no casts or protein - bleeding below kidney or caused by menstrual contamination

16

positive dipstick for blood; no RBCs seen

RBCs lysed; released hemoglobin
false positive - detects peroxidases

17

negative strip for blood; RBCs seen

ascorbic acid interference causes false negatives
RBC look alikes: yeast or crystals

18

casts

unique to kidney
matrix of uromodulin (tamm-horsfall) protein !!!
factors:
increased protein, increased acidity, high specific gravity, urinary stasis of flow
final stages (4 stages) : waxy cast

19

casts general structure

nearly parallel sides
rounded or blunt ends
various sizes & shapes

20

hyaline casts

most frequently seen
colorless; serves as basis for all casts

21

WBC cast

consists of neutrophils
proteinuria will usually also be present
renal infection
acute pyelonephritis (!)

22

RBC casts

brown to colorless
contain RBCs
glomerulonephritis!

23

epithelial casts

formed as a result of RTEs sloughing off in tubules
seen in tubular damage

24

Granular casts

degenerative process changing cellular to granular
coarse to fine to waxy
represents disintegration of cellular casts
seen in periods of stress & exercise

25

Waxy casts

broken off ends w/ cracks & fissures
seen in chronic renal disease
thought to be final phase of cellular degeneration

26

Fatty casts

represent degeneration of RTE which contain fat
seen in nephrotic syndrome

27

size of casts

broad casts vs narrow casts
wider diameter than other casts: usually granular or waxy
formed in dilated tubules or collecting ducts

28

bacteria

normal urine is free of bacteria
rods or cocci
increased numbers may indicate UTI

29

yeast

ovoid, colorless cells
budding & hyphae
vary in size
found in vaginal infection w/ urinary contamination
UTI
do not confuse with RBC

30

ways to differentiate yeast & RBC

use acetic acid to lyse RBCs
yeast are oval, budding & can be irregularly shaped