[Glomerular erythrocytes in urine. Identification and significance]

The glomerular origin of microhematuria can often be identified by typical changes in erythrocyte morphology when the urinary sediment is examined with a phase contrast microscope. The so-called "glomerular erythrocytes" appear in uneven annular shape (ring forms) or as fragmented, crushed and ruptured cells (destroyed forms). Non-glomerular erythrocytes originating from the urinary tract have different morphological characteristics. The occurrence of only a few glomerular erythrocytes (0-2 per high power field) is a normal finding. The morphological characteristics of the erythrocytes should be analyzed as the first step in the work up of microhematuria. In the case of clearcut glomerular microhematuria, unnecessary urological or radiographical investigation can thus be avoided.