Aplastic Anemia — Classification of Bone Marros Aplasia with Cytopenias — Clinical Pathway

Aplastic Anemia Clinical Pathway — All Settings

Classification of Bone Marrow Aplasia with Cytopenias

Classification of Severity

  Bone Marrow Criteria Cytopenia Criteria
Severe Aplastic Anemia (SAA)
  • BM cellularity < 25-30% of normal for age
  • OR
  • < 50% of normal cellularity for age with < 30% of cells being hematopoietic (non-lymphocytes)
  • 2 of the following must be present
    • ANC < 500/µL*
    • Platelets < 20,000/µL
    • Absolute reticulocyte count < 60,000/µL
Moderate Aplastic Anemia
  • BM cellularity < 50%
  • 2 of three cell lines below normal range for > 6 weeks, but not meeting criteria for SAA:
    • ANC < 1500/µL
    • Platelets < 100,000/µL
    • Anemia with absolute reticulocyte count < 60,000/µL

*Very severe aplastic anemia is defined as an ANC < 200/µL, otherwise meeting criteria for SAA

Causes of Bone Marrow Aplasia Based on Diagnostic Evaluation

Result of Diagnostic Evaluation Likely Diagnosis
Abnormal chromosomal breakage study Fanconi anemia or related disorders
Lymphocyte telomere length analysis below 1 percentile Dyskeratosis congenita/telomere biology disorders
Germline mutation in SBDS gene Shwachman-Diamond syndrome
Classic somatic cytogenetic lesions/increased blasts Myelodysplastic syndromes (MDS)/leukemia
  • Elevated ferritin ( > 1000 ng/ml)
  • Elevated triglycerides
  • Decreased fibrinogen, hepatosplenomegaly, hemophagocytosis
 Hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS)
None of the above abnormalities Idiopathic acquired aplastic anemia