Significance of Pus cells (pyuria)
•Physiological causes: (0-4 leukocytes/HPF) may be present
- Chronic pyelonephritis.
- Renal stones.
Squamous epithelial cells Transitional epithelial cells
Distal urethra and vagina. mucosa of bladder, ureters
and pelvis of kidney.
Significance:- Normally a few epithelial cells are seen in normal
urine, more common in females and reflect normal sloughing of these
When these cells are present in large number along with leukocytes,
they are indicative of inflammation.
• They are cylindrical in shape with rounded ends (mostly).
• The basic structure of casts is "Tamm-Horsfall mucoprotein protein,
which secreted by tubular cells.
• Cast are unstable & deteriorate with time specially in dilute &/or
• Essential materials for cast formation
Mould Renal tubules
Protein Tamm-Horsfall mucoprotein
Hyaline cast: It is basic protein cast. These are cylindrical,
colorless homogeneous and transparent.
• Hyaline casts can be present in low numbers (0-1/LPF) in
concentrated urine of normal patients, not always associated with
• Greater numbers of hyaline casts may be seen in association with
proteinuria of renal (e.g., glomerular disease) or extra-renal origin
(e.g., overflow proteinuria as in myeloma).
• In such cases it has been proposed that the presence of excessive
serum protein in the tubular lumen promotes precipitation of the
Cellular casts: most commonly observed in diseases which cause
degeneration, necrosis or sloughing of tubular epithelial cells
It can be
Acute tubular necrosis.
Red cell cast
)have a yellowish orange
• Acute glomerulonephritis
• Renal infarction.
• Acute pyelonephritis.
• Interstitial nephritis.
• Acute glomerulonephritis
It is rarely possible to distinguish between epithelial casts and leukocyte casts
Granular cast: it can be of either
• Formation: from degenerating cells or solidification of plasma
• It’s common in advanced renal diseases as, chronic nephritis and
Waxy cast (Renal failure casts):
• Waxy cast are yellowish homogeneous,britle with
irregular blunt or cracked ends( square cutted) and
have high refractive index ( so more visible than
hyaline under microscope).
• It’s common in chronic renal failure.
• They contain fat globules of varying size which are highly refractile.
• Fat in the cast is cholesterol or triglycerides.
• They are passed in urine in the following conditions:
• Nephritic syndrome.
• Fat necrosis.
3- Miscellaneous structures
They are occasionally seen in normal urine of intact male animals.
They have no significance.
B. Parasites Parasitic ova in urine sediment are from parasites in the
urinary system or fecal contamination of the urine samples.
• The urine may contain;
• Trichomonas vaginalis………..more common in females.
• Dictophyma renal……………..kidney worm of dogs.
• Cappillaria plica………………bladder warm of dogs and cats.
Candida are budding yeast cells can be seen in urine in animals with UTI
D. Tumor cells : which having all the characteristics of malignancy may
be seen singly or in groups in urine. These tumor cells could be from
kidney, ureter, bladder and urethra.
These cells are examined after staining of urine sediment.
1- Fat droplets
Fat droplets are lightly tinged green, highly refractile, round bodies of
varying size. Presence of fat in urine called "lipuria".
* In most cats, lipuria appeared to some degree because the kidneys of
cats contain a large amount of lipid.
Scattered fat droplets appeared in urine in the following conditions:
2- Crystals: The type of crystals formed depends on urine pH
Acidic PH crystals Alkaline PH crystals
• Calcium oxalate. • Amorphous phosphate.
• Uric acid. • Triple phosphate
• Amorphous urate. • Calcium carbonate.
• Leucine. • Ammonium biurate.
It present in acidic and neutral urine.
It present in small numbers in the urine of healthy dogs.
Ethylene glycol poisoning especially monohydrate form
2- Uric acid crystals
They appear as yellowish brown granular precipitate in the form
clump and dissolve on heating. When they are made of sodium
urate, they are needle like in the form of thorn apple.
They are passed more often in patients
4- Amino acid crystals
Dark and needle like. Often
found in small clusters or
2. Leucine crystals
Large spheroids with
associated with sever liver
diseases in human, but not
been commonly found in
3- Cystine crystals
Significance: There is a metabolic defect
affecting the transport of cystine and other
amino acids across the renal tubules.
These animals are prone to the formation
of cystine uroliths,(cystinuria)
1- Amorphous phosphate crystals
They can be present in large amounts
but have no clinical significance.
2- Triple phosphate crystals
prism like appearance with tapering sides
and ends "coffin-lid”
It may be found in animals with struvite
uroliths which are often associated with
Staphylococcus urinary tract infections
They are round with many lines radiating from their centers
and may also have a short dumbbell-shape.
4- Ammonium biurate crystals
They are brown and round with long spicules
(thorn apple shape). These
spicules occasionally break off the
main part of the crystal and appear
as small brown crystals with fine
1. Animals with liver diseases especially in those with
1. In Dalmatians; due to altered purine metabolism in
2- Bilirubin crystals
When increased in no.
Indicate severe hemolytic anemia or severe
liver or biliary disease.
3- Cholesterol crystals
They are large flat structures with distinct right angles.
They may be rectangular but usually appear as two or more
rectangles joined together.
They are not commonly found and their significance is
unknown, but they may be found in the urine of animals with
previous urinary tract hemorrhage or degenerative diseases.