Cylindruria

Abstract

Abstract:The morphological analysis of urine sediment is an essential part of urinalysis and casts are important elements of urinary sediment. Their shape is typically cylindrical, with extremities often rounded. Casts form within the renal tubules and are made of Tamm-Horsfall glycoprotein (THG). Under some physiological or pathological conditions THG fibrils aggregate giving rise to casts, whose formation is favoured by a number of factors including high urine osmolality and/or low pH. Casts can be found in normal subjects, in non-renal conditions, such as fever, dehydration, and acute heart failure as well as in virtually all renal diseases. Casts can be classified on the basis of their morphology as hyaline, granular, waxy, fatty, cellular (leukocytic, erythrocytic, epithelial), containing crystals or microorganisms, pigmented and mixed. As the correct identification of casts is crucial for an accurate and timely diagnosis of renal disorders, laboratory professionals should be trained to identify and classify casts properly.

The role of organic urine sediment analysis in the monitoring of renal diseases

“…The casts are important components of the urine sediment as they can be associated with a number of renal disorders whose diagnosis may also be proper urine identification (Rizzi et. al, 2017;Caleffi and Lippi, 2015;Chew and Di Bartola, 2004). It is also necessary to know that urine sampling after intense physical activity can cause, among other things, severe cylindruria.…”

“…In addition, there is a large amount of amorphous phosphates and crystals. (Fogazzi, 2010;Caleffi and Lippi, 2015).…”

“…It is not advisable to examine too alkaline urine because such an environment prevents the formation of casts and favors the lysis of other cellular elements. Additional conditions that may violate the exact identification and classification of casts include: contamination of the sample with genital secretions, the presence of large amounts of amorphous phosphates and crystals, as well as the urine of low urine specific gravity (Fogazzi, 2010;Caleffi and Lippi, 2015). The cylinders faithfully depict the inner tubular lumen of the ascending parts of the Henle loop, the distal tubules or the kidney collection canals, where they are created.…”

“…Indications for cytological examination of the urine are: screening of asymptomatic patients exposed to carcinogens, triage of symptomatic patients, detection of non-neoplastic, premalignant and malignant lesions, metastatic tumors, lesions that cannot be detected by cystoscopy or biopsy, and monitoring of therapy (Ostović, 2015). First of all, an identification of the urinary sediment is crucial for the accuracy and timely diagnosis of renal disorders (Caleffi and Lippi, 2015).…”

“…However, the total accuracy of these instruments in identifying (erythrocytes, leukocytes, epithelial cells, casts) is questionable. The gold standard for the study of urinary sediment elements, or the best identification, is still based on traditional, phasecontrast microscopic, manual analysis with low and high power magnification (Bogaert etal., 2016;Caleffi and Lippi, 2015;European Confederation of Laboratory Medicine, 2000;Clinical and Laboratory Standard Institute, 2009). This review article focuses on pre-analytic and analytical factors that influence the urinary sediment identification, as well as on the normally expected sediment elements and the clinically relevant interpretation of abnormal findings of urinary sediment in some renal diseases.…”