Diagnostic Criteria for Aplastic Anemia

Diagnostic Approach

The diagnosis of aplastic anemia requires a comprehensive evaluation, including peripheral blood and bone marrow assessment, to distinguish it from other hypocellular disorders, according to the European Hematology Association 1, 2
Bone marrow biopsy is critical and necessary for diagnosis, showing severely reduced cellularity (<20% in severe cases), corrected for patient age, as recommended by the European Hematology Association 1, 3
The examination of at least 100 cells to assess for dysplasia of granulocytes and presence of blasts is essential, as stated by the European Hematology Association 2, 4

Aplastic anemia can be distinguished from hypocellular myelodysplastic syndrome (H-MDS) by the absence of moderate to severe erythroid dysplasia and abnormal sideroblasts, as noted by the European Hematology Association 1, 3
The presence of clusters of immature precursors (ALIP) in a hypocellular setting is characteristic of hypocellular acute myeloid leukemia (H-AML), not aplastic anemia, according to the European Hematology Association 4, 3

Age correction is necessary when assessing bone marrow cellularity to avoid misdiagnosis, as emphasized by the European Hematology Association 3
Careful exclusion of hypocellular variants of MDS and AML is critical, as treatment approaches differ significantly, as stated by the European Hematology Association 2
Previous genotoxic exposure or therapy must be excluded as they can cause hypocellular marrows resembling aplastic anemia, as noted by the European Hematology Association 1

Bone marrow aspirate with 500 cell differential is necessary to examine for dysplasia of erythroid precursors, granulocytes, and megakaryocytes, as recommended by the European Hematology Association 5, 6
Iron stain for ring sideroblast assessment is used to exclude MDS, with a study published in Haematologica in 2009 supporting its use 5
Standard cytogenetics/interphase FISH is used to rule out chromosomal abnormalities, as suggested by the European Hematology Association 5, 6
Flow cytometry is used to assess for abnormal phenotypes, with the International Society for Laboratory Hematology recommending its use 5
PNH screening by sensitive flow or molecular screening technique is necessary, as recommended by the European Hematology Association 5
Reticulin stain is used to assess for fibrosis, with a study published in Haematologica in 2009 supporting its use 5