The (fixed) urinary sediment, a simple and useful diagnostic tool in patients with haematuria

Examination of the urinary sediment is a simple and indispensable tool in the diagnostic approach to patients with asymptomatic haematuria. Various glomerular and nonglomerular diseases can cause haematuria. A well-trained expert can distinguish between these two forms of haematuria by examining the urinary sediment under a simple light microscope. In glomerular haematuria, dysmorphic erythrocytes and erythrocyte casts are found, whereas in nonglomerular haematuria the erythrocytes are monomorphic and erythrocyte casts are absent. However, few people have sufficient expertise in the examination of the urinary sediment, and consequently this investigation is performed far too seldom. A few years ago, a simple method of fixation of the urinary sediment became available. Fixed specimens can be stored at room temperature for at least two weeks, which enables the sending of a fixed specimen to an expert examiner by regular mail. In this way, the urinary sediment can more frequently be used as the initial investigation in the diagnostic route of patients with asymptomatic haematuria.