Urinary cast is cylindrical structures produced by the kidney and present in the urine in certain disease. They are produced by the distal convoluted tubule and collecting ducts of nephrons, then dislodge and into the urine. We can detected by microscopy examination.
They are produced via precipitation of Tamm-Horsfall mucoprotein which is secreted by nephritic cells, and sometimes also by albumin in conditions of proteinuria. Cast formation caused by protein denaturation and precipitation (low flow, concentrated salts, low pH). Tamm-Horsfall protein is particularly susceptible to precipitation in these conditions.
As reflected in their cylindrical form, casts are generated in the small distal convoluted tubules and collecting ducts of the kidney, and generally maintain their shape and composition as they pass through the urinary system. Although the most common forms are benign, others indicate disease. All rely on the inclusion or adhesion of various elements on a mucoprotein base?the hyaline cast. "Cast" itself merely describes the shape, so an adjective is added to describe the composition of the cast. Various casts found in urine sediment may be classified as follows.