RBCs may also be found in the urine sediment. They are smaller than WBCs and do not have nuclei. They may be disc- or spherical-shaped, or may have a spiked or crenated appearance. The top image illustrates the disc shape and crenated appearance.
The presence of large numbers of RBCs in the sediment is associated with damage to the glomerular membrane or vascular injury within the genitourinary tract. The bottom image is an unstained urine sediment that contains numerous RBCs.
Note that RBCs may also be contamination, if the urine specimen was collected from a female patient during menses.