The number of platelets in adult blood is (1-3) × 10 per L, with a diameter of 2-3 um. Platelets are viewed as nonfunctional cellular debris in the blood over a long period of time. Platelets have a specific morphological structure and biochemical composition and are present in relatively constant numbers in normal blood (e.g., 100-300,000/mm in humans) and have important roles in physiological and pathological processes such as hemostasis, wound healing, inflammatory responses, thrombosis, and organ transplant rejection.
Plates are found only in mammalian blood and have no nuclear structure, i.e., no chromosomes.
Thrombocytopenia is defined as a platelet count of less than 100,000/ml (100 x 10/L) in the peripheral blood.
Clinically, thrombocytopenia is classified according to the cause of thrombocytopenia: primary thrombocytopenia and secondary thrombocytopenia. Secondary thrombocytopenia is most often seen in leukemia, aplastic anemia, myelodysplastic syndrome (MDS), paroxysmal sleep hemoglobinuria (PNH), and hypersplenism, etc. Treatment is largely based on the primary cause and requires platelet input to prevent hemorrhage if necessary.