Final Answer:
The type of red blood cells (RBCs) found on peripheral blood smear (PBS) in thalassemias includes hypochromic, microcytic RBCs with anisocytosis and poikilocytosis.
Step-by-step explanation:
1. *Peripheral Blood Smear (PBS):* This is a diagnostic test where a thin layer of blood is spread on a glass slide and examined under a microscope to assess the characteristics of blood cells.
2. *Thalassemias:* Thalassemias are a group of inherited blood disorders characterized by abnormal hemoglobin production and reduced red blood cell synthesis.
3. *Hypochromic:* Refers to RBCs that have a decreased concentration of hemoglobin, resulting in a paler color. In thalassemias, the production of normal hemoglobin is impaired, leading to hypochromic RBCs.
4. *Microcytic:* Describes RBCs that are smaller than usual. Thalassemias often lead to microcytic RBCs due to the underproduction of hemoglobin.
5. *Anisocytosis:* Indicates variability in the size of RBCs. Thalassemias can cause anisocytosis as a result of irregularities in RBC production.
6. *Poikilocytosis:* Refers to the presence of abnormally shaped RBCs. Thalassemias may lead to poikilocytosis due to the defective synthesis of hemoglobin.