Peripheral Blood
The formed elements of peripheral blood include red blood cells (RBCs), white blood cells (WBCs) and platelets.
Except for a small percentage of slightly immature RBCs, i.e., reticulocytes, the RBCs are homogeneous.
WBCs include a) nongranular leukocytes, i.e., lymphocytes and monocytes, and b) granular leukocytes, i.e., neutrophils, eosinophils and basophils.
Platelets are small, non-nucleated cell fragments.