Urinalysis identification

Squamous epithelial cells

- Originates from vagina, vulva or prepuce

- Distal urinary system

- Largest epithelial cells

- Flat, irregular shaped, small round nucleus

- Not a significant finding

Transitional epithelial cells

- Originates from bladder, ureters, renal pelvis, or proximal urethra

- Round or pear shaped

- Granular appearance

- Larger nucleus

Renal epithelial cells

- Normal to see 0-1 in each field

- Increased number indicates cystitis, pyelonephritis, or renal tubule disease

- Come from kidneys

- Smaller than other cells but slightly larger than WBCs

- Large, round nucleus

Bacteria

- Small amount seen in free catch

- Should see none in cysto or catheterization

- Look for background movement

- Rods or cocci

- Identify on high dry

- Indicates UTI

Yeast

- Rare

- Colorless, oval, double refractile walls

- Often confused with RBCs or lipids

- Caused by contamination

Fungi

- Rare

- Hyphae (branches)

- Very serious -- let doctor know immediately

Hyaline casts

- Most basic

- Clear, colorless, and highly refractile

- Parallel sides and rounded ends

- Can be easily obscured if light is up too high (have dim light)

- Low numbers are normal

- Seen with exercise or stress

Granular casts

- Most commonly seen

- Due to degeneration of renal epithelial casts or WBC casts

- Course or fine

Epithelial cell casts

- Picked up from cell walls or tubule walls

- Stay in tubules long enough → degenerates into coarse granular cast then fine granular cast

- Indicates renal cell necrosis or tubular damage

RBC/erythrocyte casts

- Appear yellow/orange color

- Stained - purple/pink color

- Indicates bleeding in renal tubules

WBC/leukocyte casts

- Slightly larger than RBCs

- Granular appearance

- Indicates inflammation of kidneys

Waxy casts

- Last stage in degeneration process

- Does not have parallel sides

- Broken, craters

- Edges more blunt

- Wider than hyaline

- Indicates severe damage to renal tubules

Fatty casts

- Seen more frequently in cats with renal disease or dogs with diabetes

- Have small fat droplets

Cylindroid casts

- Look similar to hyaline casts but have tapered end

- Not really any indications

Ammonium biurate crystals

- Brown, three-dimensional spheres

- Smooth or irregular edges (thorny apple)

- Seen with liver disease

Amorphus urate crystals

- Result of precipitation

- Many different shapes and sizes

- Not a concern

Uric acid crystals

- Diamond or rhomboid shape

- Yellow to yellow-brown in color

- Not common in dogs in cats except for dalmations

Bilirubin crystals

- Shaped like branching needles, twigs, or antlers

- Amber/bourbon color

- Common in acidic urine

- Not normally a concern

Struvite crystals

- Also called triple phosphates

- Shaped like a coffin lid (6-8 sided prism) with tapered edges

- Most common

Calcium oxalate dihydrate crystals

- Square with Xs or envelope shaped

- Found in small numbers in dogs and horses

Calcium oxalate monohydrate crystals

- Shaped like barbells or picket fences

- Typically seen with antifreeze poisoning

Tyrosine crystals

- Dark, needle-like projections

- Highly refractile

- Indicate liver disease

- Not common in dogs and cats

Leucine crystals

- Shaped like a pin cushion or wheel

- Yellow or brown in color

- Indicate liver disease

Cystine crystals

- Flat, 6-sided (hexagonal) shape

- Thin and colorless

- Indicates renal tubular dysfunction or cystine bladder stones

Amorphous phosphates crystals

- Almost identical to amorphous urates

- Granular appearance

- Different sizes and shapes clumped together

- Due to refrigeration or urine sitting out

Calcium carbonate crystals

- Round with many radiating lines outwards

- Commonly seen in horses and rabbits

- No indications, not a concern

Mucus threads

- Look like folding ribbons

- Seen in equine urine

Sperm

- Seen in intact males

- Have head and tail

- Die in fridge

Capillaria plica

Bladderworm of dogs and cats

Dioctophyme renale

Kidneyworm of dogs

Stephanurus dentatus

Kidneyworm in pigs

Fat droplets

- Highly refractile, round, vary in size

- Appear orange/red with sudan III stain

- Can be an artifact of catheterization due to lubrication of catheters

- Free-catch or cysto - typically seen in cats, dogs with diabetes, fat animals, high-fat diet