Serum- A yellowish fluid obtained from the blood after the formation of clot. Serum contains all the Proteins, Metabolites, Hormones, Electrolytes except for cells and clotting factors. In Serum, the blood cells stick together and form a mesh-like structure that is commonly called a Clot. Serum therapies are widely used for the treatment of Hair problems, Chronic Urticaria etc.
Plasma- A yellowish fluid obtained from the blood in which blood cells are freely present without any clot. In plasma, All the Proteins, Metabolites, Hormones, Electrolytes as well as Clotting factors are present.Plasma is commonly transfused in the patients suffering from Hemophilia, Burn patients and Clotting Disorders.
For further details you can refer to this blog- https://paramedicsworld.com/hematology-practicals/difference-between-serum-and-plasma/medical-paramedical-studynotes