Urinalysis in dogs and cats, part 1: physical and chemical urinalysis

Abstract

The urinalysis of dogs and cats is an important part of the diagnostic evaluation of urinary tract diseases as well as for the identification of systemic diseases. A routine urinalysis consists of a physical and chemical examination of the urine as well as an examination of the urine sediment. Various urine collection methods (free-catch, catheterization, cystocentesis) are available. Each method has multiple advantages and disadvantages. The appropriate method must be chosen individually for each patient depending on the emphasis of the examination. The urine should ideally be examined within 30 minutes of collection as it is prone to change due to time and storage. Physical examination of the urine consists of the determination of urine color, clarity, and specific gravity which provides information regarding the concentration of the urine. The latter is determined by refractometry and needs to be interpreted in the context of the hydration status of the patient. Chemical examination of the urine consists of the determination of the pH value and the presence of blood/hemoglobin/myoglobin, protein, glucose, bilirubin, urobilinogen, nitrite, and ketones. The use of commercially available urine dipsticks is common. These must be stored and used according to the manufacturer's instructions and when interpreting the results, veterinary aspects need to be taken into consideration. The physical and chemical examinations of the urine represent rapid and readily performable methods that provide important information for the diagnosis or the exclusion of numerous diseases.