Red blood cells (RBCs) may also be found in the urine sediment. They are smaller than WBCs but do not have a nucleus. They may be disc- or spherical-shaped or have spiked or crenated appearance. The top image illustrates the disc shape and crenated appearance.
Large numbers of RBCs in the sediment are associated with damage to the glomerular membrane or vascular injury within the genitourinary tract. The bottom image is unstained urine sediment that contains numerous RBCs.
RBCs may also be considered contamination if the urine specimen is collected from a female patient during menses.
