Microscope: urine sample Flashcards
Unstained sediment, urine with blood
White blood cells (green arrow) (larger, granular appearance)
Red blood cells (blue arrow) (smaller, more regular, may be reddish)
Fat droplets
More variable in size, slightly greenishtinged (or refractile), have a darker edge, are more globular shape, usually float to the top of the coverslip – other constituent may be out of focus
RBC
Normal: Up to 5 RBC/pole of vision are acceptable
Round, slightly red-tinged, smooth textured cells, may be biconcave in fresh urine or spiky (crenated) in stored urine
May lyse in very alkaline or dilute (USG < 1.008) urine
White blood cells
Normal: up to 5 WBC/ pole of vision are considered acceptable - these are normally segmented neutrophils
Round, colorless cells with a grainy texture may see nuclei of cells
May lyse in very alkaline or dilute (USG < 1.008) urine
WBC masses
WBC (yellow arrow)
Bacteria (white arrow)
Transitional epithelial cells
• From renal pelvis, ureters, urinary bladder and/or urethra
• Variable size and shape (depends on origin): round or polygonal, pear-shaped, caudate (pelvis), tailed, spindle
• Can be seen in normal urine (few in samples collected by mid-stream catch or cystocentesis, more in catheterized specimens due to catheter-induced sloughing) as single cells or small clusters, more may exfoliate with inflammation
Squamous epithelial cells
• Largest cell in urine, small amount normal
• Thin, flat cells, with angular border, anuclear or small central nuclues, present as single cells or in variably-sized clusters
• Represent contamination (from skin, genital tract, prepuce in male dogs) in voided urine or may reflect squamous metaplasia of prostate (from exogenous estrogen or an estrogen-secreting Sertoli cell tumor) especially if in large numbers
Neoplasia
May exfoliate into urine in animals with tumors of the genitourinary tract
Most common type is transitional cell carcinoma (TCC) - in urinary bladder, urethra (including prostatic urethra in dogs).
Rarely, lymphomas and renal carcinomas
Display cytologic criteria of malignancy such as variation in cell and nuclear size. Frequently exfoliate as variably sized irregular clusters.
TCC: The epithelial cells exhibit anisocytosis, anisokaryosis, nucleolar rings, basophilic cytoplasm, and have an increased N/C ratio (WrightLeishman stain).
Hyaline casts: more visible with regular light microscopy if fat sticks to the protein matrix (Tamm-Horsfall mucoprotein) that makes up the hyaline cast (hyaline with fat) or particulate material from degenerating cells is present within the cast matrix (hyaline to finely granular cast).
Cellular casts: have distinct cells within the protein matrix – named according to cell origin (WBC, RBC or epithelial casts)
Granular casts: cells within the protein cast matrix break down, the cast becomes coarsely then finely granular.
Waxy casts: are the final stage of cast degeneration. They have a smooth appearance, no internal texture, and are more refractile than the surrounding urine.
