MICROSCOPIC EXAMINATION OF URINE Flashcards
memorization
Average range specimen volume for urinalysis:
Recommended volume:
Average range: 10 - 15 mL
Recommended: 12 mL
Centrifuge tube at ____ RCF for ___ minutes:
Centrifuge tube at 400 RCF for 5 minutes
Transfer 20 uL (0.02 mL) sediment to glass slide with _______ mm coverslip
22x22 mm coverslip
Examine microscopically (___ LPF, ____ HPF, under ____ light)
10 LPF
10 HPF
Under reduced light
Quantitative measure of formed elements of urine using hemacytometer
Addis Count
Specimen used for Addis count:
12-hour urine
Preservative used for Addis count:
Formalin
Normal values in Addis count:
RBCs =
WBCs & ECs =
Hyaline casts =
RBCs = 0 - 500,000/12-hr urine
WBCs = 0 - 1,800,000/12-hr urine
Hyaline casts = 0 - 5000/12-hr urine
Located in the objective & is adjusted to be near the specimen:
First lens system
Located in the eyepiece (ocular lens)
Second lens system
Used to clean the optical surfaces of the microscope:
lens paper
Used to remove dust on the optical surface of the microscope
Camel-hair brush
Used to clean any contaminated lens
Commercial lens cleaner
To remove oil on lens, use:
- use dry lens paper
- then lens paper moistened w/ lens cleaner
Using xylene to remove oil on lens is recommended
true or false
False
Using xylene to remove oil on lens is not recommended due to its toxic fumes
Lenses which forms primary (initial) image of specimen
Objectives
moves stage noticeably up & down, bringing slide into view
Coarse Focus knob
Sharpens the image
Fine focus knob
Microscope for routine urinalysis
Bright-field (BF) microscopy
Enhances visualization of translucent elements (i.e. with low refractive indices [e.g. casts])
Phase-contrast microscopy
To convert BF to PC:
Replace objective lens & condenser with PC objective lens & PC condenser
To convert BF into polarizing:
Add 2 filters (1 below the condenser, 1 between objectives & oculars)
Detects the presence or absence of birefringence; for identification of cholesterol in oval fat bodies, fatty casts, and crystals.
polarizing microscopy
It is the ability of an element to refract light in2 dimensions at 90 degrees to each other
Birefringence
for identification of Treponema pallidum
Dark-Field (DF) microscopy
To convert BF into DF:
Replace the condenser with a DF condenser that contains an opaque disk
For visualization of fluorescent substances and microorganisms
Fluorescence microscopy
3-D microscopy image & layer-by-layer imaging of a specimen
Interference-contrast microscopy
Can be adapted for interference microscopy:
Bright0field microscopy
2 types of interference-contrast microscopy:
- Nomarski (Differential interference contrast)
- Hoffman (Modulation contrast)
Delineates structure & contrasting colors of the nucleus & cytoplasm; Identifies WBCs, epithelial cells and casts; most commonly used supravital stain:
Sternheimer-Malbin (SM)
(Crystal violet + Safranin O)
Enhances nuclear detail; Differentiates WBCs and RTE cells:
Toluidine blue (supravital stain)
Lyses RBCs, enhances nuclei of WBCs; Distinguishes RBCs from WBCs, yeast, oil droplets & crystals
2% acetic acid
Stains triglycerides and neutral fats orange-red; Identifies free fat droplets & lipid-containing cells & casts.
Lipid stains
- oil Red O
- Sudan III
Differentiates Gram-positive & -negative bacteria; Identifies bacterial casts
Gram stain
Stains eosinophilic granules; Identifies urinary eosinophils
Hansel stain (Eosin Y + Methylene blue)
Stains structures containing iron; identifies hemosiderin granules
Prussian blue (Rous test)
Stains DNA
Phenathridine (orange)
Stains nuclear membranes, mitochondria & cell membranes
Carbocyanine (green)
NV of RBCs in microscopy
NV = 0-2 or 0-3 / HPF
RBCs in HYPERTONIC URINE:
Crenated/Shrink
RBCs in HYPOTONIC URINE:
Swell/Hemolyze (Ghost cell)
RBC in glomerular membrane damage:
Dysmorphic with projections, Fragmented (acanthocytes)
Sources of error of RBCs in microscopy:
Yeasts
Oild droplets
Air bubbles
Monohydrate calcium oxalate crystals
Remedy for sources of error of RBCs:
Add 2% acetic acid. It will lyse the RBCs but not the others
NV of WBCs in urine microscopy:
NV = 0-5 or 0-8 / HPF
WBCs in HYPOTONIC urine:
they swell and granules undergo BROWNIAN MOVEMENT, producing a sparkling appearance (Glitter cells)
Using Sternheimer-Malbin Stain, glitter cells stain _______, and leukocytes stain _______
Sternheimer-Malbin Stain:
Glitter cells - pale blue
Leukocytes - pale pink
Significant value of eosinophils in urine: ___%
> 1% (seen in acute interstitial nephritis)
largest cell with abundant, irregular cytoplasm & prominent nucleus
Squamous epithelial cells (SEC)