Leukocytes white blood cells, or WBCs play a role in the body's immune response. They are less numerous than RBCs and most are short-lived. The objective of coagulation is to convert soluble fibrinogen into insoluble fibrin. As this occurs, blood cells and platelets get stuck in the net of fibrin, stopping blood loss. After a clot forms, it undergoes clot retraction within 30 minutes.
Fibroblasts invade and strengthen the clot.