Definition: A condition most frequently caused by bacteria (usually >10^5/mL).
Bacteria and polymorphonuclear leukocytes are the distinguishing urinary sediment particles. Other particles which may be found include transitional epithelial cells and isomorphic erythrocytes. When the infection involves the kidney parenchyma also leukocytic casts and epithelial renal tubular cells, either free or within casts, can be observed.