Mircoscopic examination of urine Flashcards
How much urine is used?
12 mL
Centrifugation
speed: 400-450 g for 5 minutes, no brake.
urine volume to resuspend sediment ration
12:1 ratio desired
Low power objective?
10x objective, examine perimeter of cover-slip, look for squamous epithelial cells, casts, and mucus. Scan minimum of 10 fields
high power objective?
40x, examine center area and look for RBC/WBC< transitional and renal tubular epithelial cells, bacteria, yeast, sperm, trichomonads, crystals
Red blood cells:
intact RBC: hematuria
normal: 0-3/hpf
abnormal: damage to basement membrane of glomerulus, kidney infection, kidney stones, trauma
What do RBC look like?
smooth biconcave discs, no nucleus
Crenate RBC
seen in concentrated urine( high SG), water leaves RBC
Ghost RBC
occurs in dilute urine when RBC swells and water enters cell and burst
What do RBC resemble?
yeast, oil droplets, air bubbles, calcium oxalate crystals, WBC
WBC: leukocytes
indicates infection. normal: 0-5, neutrophil is predominant type of WBC found in urine
what do WBC’s look like?
spherical, contain segmented nucleus, granules, 2x larger than RBC, can be found in clumps
What happens to WBC in dilute urine?
WBC swell and lyse, GLitter cells
what happens to WBC in concentrated urine?
WBC become smaller, do not crenate
what can WBCs resemble?
renal tubular epithelial cells, crenated RBCS
WBC physical and chemical correlation?
physical exam: odor/clarity
chemical: positive reagent strip for leukocyte esterase, non-granular WBC will not react with reagent strip reaction (false negative)
Why are epithelial cells in urine?
normal sloughing, inflammation, renal disease, common contaminant in femal species
squamous epithelial cells
most common type, largest, originates in superficial lining of urethra and vagina, increased numbers may mean poor collection technique
Transitional epithelial cells
originates in lining of renal pelvis, ureters, bladder, and upper urethra. Increased numbers may indicate urinary tract infection, or collection by catheterization, and malignancy
renal tubular epithelial cells
originates in lining of renal tubules, increased numbers indicate tubular necrosis
squamous epithelial cells under microscope
enumerate using low power, cells are thin and flat, central nucleus, fine granulation in cytoplasm
clue cells
squamous epithelial cells with large amount of bacteria adhering to them, “shaggy”, originates in vaginal mucosa, indicates bacterial vaginal infection