Non glomerular red cells

The morfology of the blood red cells found in urinary sediment is extremely variable. To recognize some of the most typical aspects accurately can be of considerable diagnostic value since there are quite close correlations between certain pathological conditions of the kidney and the urinary tract and the morphology of the red cells in the sediment.
Using a morphological classification, a first category may include the following elements, typical of hematuria, generally caused by 'urologic' diseases:
  • biconcave red cells similar to those in the blood

Red cells morphologically similar to those in the blood (urologic hematuria)
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  • red cells that have lost their biconcave shape but still appear 'intact'. They may be disc or ballon-shaped, of spherocyte type; those of smaller dimentions are tipical of this morphological class.
The pigmentation of these red cells is often well preserved; in hypotonic urine however they may become what are known as 'ghost cells';

Ballon-shaped red cells, all of similar appearance
(calculi in the renal pelvis)
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  • crenated red cells.
All these forms can be easily reproduced suspending normal

Leukocytes and crenated red cells
(calculi in the renal pelvis; urinary infection).
These red cells come from the urinary tract
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red blood cells in solutions with varying physico-chemical properties (hypo-, iso, or hypertonic).

Urinary red cell morphology can be assessed best by fase-contrast microscopy.

Relatively normal red cells in a case of 'non-glomerular' hematuria. The outlines of the cells are brought out very clearly in phase-contrast examination
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It was Birch and Farley, and more recently Fasset (who also adopted the percentage count of the

various types of erytrocyte), who showed by this procedure that relatively normal cells with very regular or crenated outlines are most often found in 'non-glomerular' bleeding, a criterion now commonly accepted.

'Wrinkled' red cells: red blood cells suspended in urine differing in osmolality (from 400 mOsm/kg to 1000 mOsm/kg). When the urine has a very high osmolality the red cells may be quite seriously damaged; under these conditions it may be difficult to ascertain that the cellular membrane is definitely intact (phase-contrast)
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