Urinary Cast
From Anvita Health Wiki
Contents |
More Specific Terms
- broad cast
- broad, muddy brown cast
- epithelial cast
- erythrocyte cast (RBC cast)
- fatty cast
- granular cast
- hyaline cast
- leukocyte cast (WBC cast)
- mixed cellular cast
- waxy cast
Indications
- evaluation of proteinuria
Clinical-significance
- proteinuria
- translucent colorless gels formed from proteins in the tubules of nephrons
- very few casts are seen in the urine sediment of healthly individuals, except after heavy exercise ( proteinuria of heavy exercise)
- increased numbers of casts generally indicate renal disease involving many nephrons
- the Tamm-Horsfall protein forms the matrix of all casts, forming a meshwork of fibrils that trap cells, cell fragments or granular material
- plasma proteins entering the tubules (generally albumin but also hemoglobin, myoglobin or immunoglobulin light chains) increase cast formation combining with Tamm-Horsfall protein to form less lucent casts & granular casts
- cast formation increases with diminished pH, increased ionic strength & with stasis of urine within the nephron
- casts begin to disintegrate in dilute or alkaline urine or in the presence of bacteria (possibly via alkalinization)
More General Terms
References
Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 441-42
