The diagnostic criteria for aplastic anemia include a decrease in all blood cells, generally no enlargement of the liver or spleen, reduced or severe reduction in bone marrow hyperplasia in multiple sites, and exclusion of other diseases causing a decrease in all blood cells. Therefore, the diagnosis of aplastic anemia requires the following tests: complete blood count, reticulocyte count, abdominal ultrasound, bone marrow cytology, bone marrow chromosome analysis, bone marrow biopsy, rheumatoid immune indicators, and peripheral blood T-cell subgroups. Additionally, for patients suspected of having aplastic anemia, further flow cytometry and differentiation from myelodysplastic syndromes are sometimes necessary.