Evaluation of Myelodysplastic Syndrome

Essential Hematological Markers

• The American College of Hematology recommends a complete blood count with differential, reticulocyte count, and peripheral blood smear to characterize the type and severity of cytopenias 1, 2, 3
• The National Comprehensive Cancer Network suggests that a reticulocyte count is essential to evaluate bone marrow response 1, 2, 3
• The European Society for Medical Oncology states that a peripheral blood smear is crucial to identify dysplastic features such as Pelger-Huët cells, chromatin abnormalities, and hypo/degranulation in granulocytes 1, 4

Biochemical Markers for Differential Diagnosis

• The American College of Hematology recommends measuring ferritin, serum iron, transferrin, and transferrin saturation to exclude iron-deficiency anemia and evaluate iron overload 1, 2, 3
• The National Comprehensive Cancer Network suggests that vitamin B12 and folate levels should be measured to exclude megaloblastic anemia 1, 2, 3, 5
• The European Society for Medical Oncology states that haptoglobin and bilirubin are necessary to evaluate hemolysis 1, 5

Specialized Tests to Consider

• The American College of Hematology recommends flow cytometry to evaluate HPN clone in cases with clinical suspicion 1
• The National Comprehensive Cancer Network suggests that molecular testing for JAK2 mutation should be performed in patients with thrombocytosis 2, 3, 6
• The European Society for Medical Oncology states that evaluation of mutations in genes associated with myelodysplastic syndrome (including DNMT3A, ASXL1, TET2, JAK2, and TP53) can identify clonal cytopenias of uncertain significance (CCUS) 1, 7

Additional Evaluations

• The American College of Hematology recommends HLA-DR15 typing to evaluate response to immunosuppressive therapy 2, 3
• The National Comprehensive Cancer Network suggests that copper deficiency should be evaluated in appropriate cases 2, 3
• The European Society for Medical Oncology states that HIV testing should be performed if clinically indicated 2, 3

Common Pitfalls to Avoid

• The American College of Hematology warns against treating with folic acid before excluding or treating B12 deficiency, as folic acid doses >0.1 mg daily can produce hematologic remission while allowing irreversible neurologic damage to progress 5
• The National Comprehensive Cancer Network advises against relying solely on serum B12 levels, as functional deficiency can exist with "normal" values, requiring confirmation with methylmalonic acid or homocysteine 5
• The European Society for Medical Oncology states that the presence of leucocytosis does not exclude myelodysplastic syndrome, especially in overlap syndromes such as chronic myelomonocytic leukemia (CMML) 6

Laboratory Evaluation Algorithm

• The American College of Hematology recommends a step-wise approach to laboratory evaluation, starting with complete blood count, reticulocyte count, and peripheral blood smear, followed by exclusion of secondary causes, and finally evaluation of prognostic and therapeutic markers 1, 2, 3

White Blood Cell Count in Myelodysplastic Syndrome

WBC Count Patterns by MDS Subtype

• Most MDS patients present with normal to low WBC counts, typically with absolute neutrophil counts <1800/mcL defining cytopenia in prognostic scoring systems, according to the National Comprehensive Cancer Network 8, 9, 10, 11, 12
• Nonproliferative CMML is characterized by WBC ≤12,000/mcL (≤12 × 10⁹/L), classified within MDS spectrum for prognostic studies, as recommended by the National Comprehensive Cancer Network 8, 9, 10, 12
• Proliferative CMML is defined by WBC >12,000/mcL (>13 × 10⁹/L in 2017 classification), representing myeloproliferative overlap syndrome, according to the National Comprehensive Cancer Network 8, 13

Clinical Significance for Prognostication

• Absolute neutrophil count <1800/mcL defines neutropenia in the IPSS risk stratification system, which is a critical factor in determining survival and AML evolution risk, as stated by the National Comprehensive Cancer Network 8, 9, 10, 11, 12
• The number of cytopenias (0-1 vs 2-3) is one of three major independent variables determining survival and AML evolution risk, according to the National Comprehensive Cancer Network 8, 9

Critical Clinical Pitfalls

• Distinguish proliferative from nonproliferative CMML using the 12,000-13,000/mcL threshold, as this fundamentally changes classification and treatment approach, as recommended by the National Comprehensive Cancer Network 8, 9, 13