Question: what are casts in dog urine?
Answer: Casts. Urine casts are cylindric molds of the kidney tubules, formed of aggregated proteins or cells within the tubules and then passed into the urine, where they can be seen on microscopic exam. Urine from normal animals contains only a few hyaline casts (2 or less/lpf) or granular (1 or less/lpf).