Shortened erythrocyte life span is due to deletion or point mutation of the bead protein gene. What tests are required for shortened erythrocyte life span: The diagnosis can usually be made based on clinical features and laboratory tests, combined with a positive family history. When available, genetic diagnosis can be made. The peripheral blood picture shows small-cell hypochromic anemia, with varying size of red blood cells, enlarged central lightly stained area, anomalous, target-shaped, fragmented red blood cells, nucleated red blood cells, dot-colored red blood cells, multi-stained red blood cells, and Howe’s vesicles; reticulocytes are normal or increased. The bone marrow picture showed a markedly active proliferation of the erythrocyte system with a predominance of middle and late juvenile erythrocytes, and the mature erythrocyte changes were the same as in peripheral blood. The HbF content is significantly increased, mostly >0.40, which is an important basis for the diagnosis of severe β-depletion. Cranial X-ray shows thinning of the inner and outer plates of the skull, widening of the plate barrier, and vertical short hair-like bone spurs between the bony cortex. Erythropoietin: Erythropoietin (EPO) is a glycoprotein produced by the kidney. EPO may stimulate hematopoietic pluripotent stem cells to form erythroid progenitors, but it is also thought to act on erythroid lineage progenitors and subsequent cells. In stem cell culture, the addition of EPO results in both burst erythroid colony-forming units (BFU-E) and colony-forming units responsive to erythropoietin (CFU-E). In fact, EPO has an effect on cells of the entire erythroid system. Erythrocyte volume distribution width (RDW): Erythrocyte volume distribution width is a parameter that reflects the heterogeneity of erythrocyte volume size and is often based on the coefficient of variation of the measured erythrocyte volume size. (1) Increased erythrocyte volume distribution width is seen in iron deficiency anemia. In particular, an increase in the width of the erythrocyte volume distribution when the MCV is still in the reference range is characteristic of early iron deficiency anemia. (2) Decreased MCV can be seen in both ischemic anemia and thalassemia minor, but the former has increased erythrocyte volume distribution width, while the latter has normal RDW, which helps to differentiate them. (3) In hemolytic anemia and megaloblastic anemia, both MCV and erythrocyte volume distribution width are increased. In the case of aplastic anemia, the MCV and red blood cell volume distribution width were unchanged.