‘Cast’ describes the shape of aggregated particulates in urine rather than a particular substance, thus a modifier is necessary to describe the actual composition of the<unk>    ‘Cast’ simply describes a cylindrically shaped aggregation of some particulate that forms in the distal convoluted tubule or distal nephron via precipitation of a mucoprotein secreted by tubule cells (Tamm-Horsfall protein) or, in proteinuria and to a lesser extent, albumin. <unk> formation is pronounced in environments favoring protein denaturation and precipitation (low flow, concentrated salts, low pH). Unfortunately, Tamm-Horsfall protein is particularly susceptible to precipitation in these conditions.
When present on microscopic evaluation during<unk> sis,<unk>  hold significance as diagnostic and prognostic indicators of kidney disease.  As reflected in their cylindrical form,<unk>  are generated in the small tubules and collecting ducts of the kidney, and generally maintain their shape and composition as they pass the lower conveyances of the<unk>  system.  Although the commonest forms are benign, other forms are indicative of a pathologic state.  All rely on the inclusion or adhesion of various elements on a mucoprotein base – the hyaline<unk>   The various types of<unk>  that can be found in urine sediment may be classified as follows:
Urinary casts
Serum-ascites albumin gradient
Proteinuria
Bacteriuria
Beeturia
Charcot-Leyden crystals
Lipiduria
Albuminuria