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Today's Veterinary Practice May/June 2014 86 Today's Technician Peer reviewed tvpjournal.com U rinalysis (UA) provides information about the urinary system as well as other body systems. It should be performed to: • Evaluate any animal with clinical signs related to the uri- nary tract • Assess an animal with systemic illness • Monitor response to treatment. The first article in this 2-part series discussed collec- tion, sample handling, and initial evaluation of urine in small animals (March/April 2014, available at tvpjournal .com). This article will describe more detailed evaluation, including chemical analysis and microscopic examination of sediment. CHEMICAL ANALYSIS Urine chemistry test strips have multiple pads impregnat- ed with reagents that change color when the substance of interest is present. The degree of color change corre- sponds to the approximate amount of the substance pres- ent. Because color changes can be subtle, results may be con- siderably varied between indi- viduals reading the test. Several chemistry multiple- test reagent strips are available, including: • Chemstrip (poc.roche.com) • Diastix (healthcare.bayer.com) • Multistix (healthcare.siemens .com) • Petstix (idexx.com). These tests differ in the reagents used and number of tests provided (Figure 1). Urine chemistry test strip analyzers are also available and provide printed reports of results. Not all chemistry tests are useful or reliable in animal species. The test pads for urine specific gravity, urobilinogen, nitrite, and leukocytes are not used for veterinary patients. Urine pH The normal urine pH range for dogs and cats is 6 to 7.5. When a patient is ill, urine pH can be affected by acid– base status. Systemic acid–base abnormalities change urine pH because the kidneys offset the effects of pH change in the body. • Increase in urine pH (alkaline urine) may result from urinary tract infections with urease pro- ducing bacteria (that convert urea to ammonia). • Alkaline urine in a dog or cat should prompt an evaluation to determine if white cells and/or bacteria are present (often evi- dent in urine sediment). Role of Diet. In healthy pets, urine pH is most dependent on diet and whether the patient has been fasted. • Diets high in animal protein (typi- cally consumed by dogs and cats) produce a lower urine pH (acidic urine). • Plant- or vegetable-based diets (typically consumed by rumi- How to Use Reagent Strips Multiple-test reagent strips are used for urine evalu- ation by (Figure 2): 1. Laying a single strip flat on a clean paper towel, pad side up 2. Placing a drop of urine on the top or side of each test pad (depending on manufacturer instructions) 3. Reading the results after the appropriate, manu- facturer-recommended time elapses. no color change to the reagent pad is interpreted as a negative result. Urinalysis in ComPanion animals Part 2: Evaluation of Urine Chemistry & Sediment Figure 1. Multiple-test reagent strip results are compared with color scale on back of test strip bottle Theresa E. Rizzi, DVM, Diplomate ACVP Oklahoma State University Figure 2. A drop of urine is placed on or to the side of each test pad TVP_2014-0506_TT_Urinalysis-Part2.indd 86 5/25/2014 7:28:46 PM