Urinalysis is an essential component of clinical pathologic testing. It is very difficult to interpret changes in a chemistry panel (urea nitrogen and creatinine in particular) in the absence of urine, since the kidney and its ability to produce urine can dramatically affect chemistry results. Most of the urine samples we receive are from small animals (dogs and cats). This is because urine is far easier to obtain in these species than large animals. However, in an azotemic animal (high urea nitrogen or creatinine), a urinalysis can really help determine the cause of the azotemia (but is not always conclusive).
In this section of the site, information will be provided on the following:
- Overview: General information about a urinalysis.
- Sample collection: Guidelines on collecting and submitting samples for urinalysis.
- Visual features: The gross characteristics of urine that give us clues as to abnormalities that may be present in the animal, including urine color and turbidity.
- Concentrating ability: How we assess the ability of the kidneys to concentrate urine by measuring USG or osmolality
- Chemical constituents: pH, protein (Dipstick, SSA, Bence-Jones), protein-to-creatinine ratio, glucose, ketones, bilirubin, heme (“blood”) and uric acid.
- Cellular constituents: Those that are normally seen in urine including leukocytes, erythrocytes, various types of epithelial cells and sperm.
- Cell quick guide: A table compilation of the cells seen in urine and the features used to differentiate between them.
- Crystals: These include commonly seen crystals, such as struvite, bilirubin, calcium carbonate, ‘amorphous’ crystals, calcium oxalate dihydrate, and uncommonly seen crystals, such as the picket fence form of calcium oxalate monohydrate, ammonium biurate, cystine, drug-associated crystals, and other crystals (e.g. drug-associated).
- Crystal quick guide: A table compilation of common and uncommon crystals seen in urine of animals, including the pH they normally form in and distinguishing features.
- Casts: What they are, how they are formed and the different types (including diagnostic relevance). This also includes an image compilation of different casts that can be seen in urine.
- Infectious agents: That may be seen in urine, including bacteria (most common), fungi, parasites
- Other (miscellaneous) constituents: fat, mucus, contaminants
Further information is available on Urinalysis testing offered by the Animal Health Diagnostic Center of Cornell University and guidelines for urine collection.