AUBF Microscopic examination Flashcards
Specimen preparation for urine microscopic examination
Specimen should be examined while fresh or adequately preserved
Refrigeration: precipitation of amorphous urates/phosphates, other non-pathologic crystals
Warming @ 37 deg C: may dissolved some crystals
Standard specimen volume for microscopic examination
10 - 15 mL
Type of specimen for microscopic urine
Midstream clean catch urine (wash genitals before collection)
Daily urine output
1200 - 1500 mL (600 to 2000 mL is considered)
Oligouria in infants
<1mL/kg per hour
Oligouria in children
<0.5 mL per kg/hr
Oligouria in adults
<400 mL/day
failure to secrete urine
anuria
increased in urine output during night
nocturia
increase output of urine
polyuria
polyuria in adult
> 2.5 liters per day
polyuria in children
2.5 to 3mL per kg/day
Centrifugation for urine in microscopic examination
5 minutes @ 400 RCF
SEDIMENT PREPARATION
Volumes of 0.5 mL and 1 mL are frequently used (uniform amount of urine and sediment)
Conventional Glass Slide Method: Recommended volume
20 uL (0.02 mL) covered by a 22 x 22 mm glass cover slip
Power objective for detecting casts, ascertain the general composition of sediment
LPO
Power objective for identifying urinary sedminents
HPO
Method to locate casts in examining the sediment
Conventional Glass Slide Method
REPORTING THE MICROSCOPIC EXAMINATION: Average number per LPF
Casts
REPORTING THE MICROSCOPIC EXAMINATION: Average number per 10 HPF
RBCs and WBCs
REPORTING THE MICROSCOPIC EXAMINATION: Semiquantitative (Rare, Few, Moderate, Many/ 1+, 2+, 3+, 4+)
Epithelial cells, Crystals, and other sediments
Most frequently used stain in urinalysis
Sternheimer-Malbin Stain (crystal violet)
Lipid stain for triglycerides and neutral fats orange-red
Oil Red O and Sudan III + Polarizing Microscope
Do not stain cholesterol (capable of polarization)
Stain for identification of bacterial casts
Gram stain (VIAS)
Preferred stain for urinary eosinophils (drug-induced allergic reaction producing inflammation)
Hansel stain
Stains structures containing iron
Identifies yellow-brown granules of hemosiderin in cells and casts
Prussian Blue stain
Objects appear dark against a light background, most frequently used in clinical laboratory
Bright Field Microscopy
Aids in identification of T. pallidum
Dark Field Microscopy
Enhances visualization of elements with low refractive indices: hyaline casts, mixed cellular casts, mucous threads, and Trichomonas
Phase contrast microscopy
Identifies cholesterol in oval fat bodies, fatty casts, and crystals
Polarizing microscopy
Allows visualization of naturally fluorescent microorganisms or those stained by a fluorescent dye including labeled antigens and antibodies
Fluorescence microscopy
Produces a three-dimensional microscopy image and layer by layer imaging a specimen
Interference contrast
Frequently performed independently of routine urinalysis for detection of malignancies of the lower urinary tract.
Cytodiagnostic Urine Testing
Preparation of permanent slides using cytocentrifugation followed by staining with:
Papanicolaou stain
