The clinical art and science of urine microscopy

The examination of urine sediment is a diagnostic test which is frequently neglected by nephrologists. With this review the authors wanted to demonstrate that it can provide useful and relevant information in a wide spectrum of clinical situations.

The authors reviewed the main contributions dealing with urine sediment examination, published in international journals in the period from January 2002 to April 2003. After a section on methodological aspects, they described the importance of urine sediment examination in various diseases of the urinary tract. These included bladder B-lymphoma, systemic histoplasmosis, urate nephropathy, Fabry disease, myeloma cast nephropathy, giant cell arteritis, and lupus nephritis. The significance of 'decoy cells' in the urine as a marker of polyomavirus BK reactivation was also discussed, both in renal transplantation and other conditions such as solitary pancreas transplantation, chronic lymphatic leukaemia, and HIV infection. In the section devoted to urine sediment changes caused by drugs the authors dealt with leukocyturia induced by indinavir, and crystalluria, which can follow amoxycillin and acyclovir administration. Finally, they reported on the utility and limits of flow cytometry for the automated analysis of urine sediments.

The review of the recent literature on urine sediment examination shows that this test has important clinical implications in a large spectrum of diseases. Therefore, it should be more widely used by nephrologists.