Page 2620 - Cote clinical veterinary advisor dogs and cats 4th

1332 Crystals, Urine Sediment

VetBooks.ir Common in dogs (infec- Infrequent in healthy patients
except Dalmatians and
tion) and cats (nutrition),
English bulldogs; if numerous,
especially with alkaline
urine or as artifact suggests liver dysfunction
or shunt in dogs and cats

Ammonium magnesium phosphate Ammonium biurate
(triple phosphate, struvite)

Associated with Suggests ethylene
bilirubinuria glycol intoxication

Bilirubin Calcium oxalate monohydrate

Seen in healthy
patients; suggests Seen in healthy dogs
ethylene glycol
intoxication

Calcium oxalate dihydrate Calcium phosphate

Rare; suggests liver Uncommon in healthy
disease or primary dogs; may occur with
cyst(e)inuria hypercholesterolemia
(e.g., breed-related) or renal disease

Cyst(e)ine Cholesterol

Sulfa, contrast media; Rare; should be
renal elimination distinguished from calcium
oxalate monohydrate
of material
(history, physical exam)

Drug crystals Hippuric acid
CRYSTALS IN URINE SEDIMENT

Drug Effects Specimen Collection and Handling avoid misidentifying calcium oxalate mono-
Crystals may form with urinary excretion of Process immediately for best results. If refriger- hydrate crystals as calcium carbonate crystals,
certain antibiotics (e.g., sulfonamides) and ated, allow urine to reach room temperature which do not occur in the urine of cats and
radiographic contrast agents. before analyzing. dogs.
Lab Artifacts Relative Cost: $ (as part of urinalysis) AUTHOR: Shannon D. Dehghanpir, DVM, MS, DACVP
Evaluation of fresh urine yields most accurate EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
results, as delayed sampling and refrigeration Pearls
(storage) can dissolve or promote crystal forma- There are several variations of calcium oxalate
tion, respectively. monohydrate crystals. Care must be taken to
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