What is the appropriate workup for suspected myelodysplastic syndrome?

MDS Workup

The workup for suspected myelodysplastic syndrome requires bone marrow aspiration with iron stain and biopsy, cytogenetics, complete blood count with differential and peripheral smear examination, plus exclusion of reversible causes of cytopenias through specific laboratory testing. 1

Mandatory Initial Evaluation

History and Physical Examination

• Document duration of cytopenias (must be persistent for at least 4-6 months, or 2 months if accompanied by specific karyotype or bilineage dysplasia) 1
• Prior chemotherapy, radiation therapy, radioimmunotherapy, or radioiodine exposure 1
• Occupational or hobby exposure to benzene 1
• Current medications, alcohol intake, smoking history 1
• Bleeding/bruising tendency and infection history 1
• Family history focusing on inherited bone marrow failure disorders (Fanconi anemia, telomere disorders, dyskeratosis congenita—especially in younger patients) 1
• Complete physical examination including spleen size assessment 1
• Transfusion history documentation 1

Required Laboratory Tests

Hematology Studies

• Complete blood count with differential 1
• Platelet count 1
• Reticulocyte count 1
• Peripheral blood smear examination for dysplasia in erythrocytes (anisocytosis, poikilocytosis, basophilic stippling), granulocytes (pseudo Pelger-Huet cells, hypogranulation), and platelets (giant platelets, anisometry) 1

Biochemistry Studies to Exclude Reversible Causes

• RBC folate and serum B12 (to exclude megaloblastic anemia) 1
• Serum iron, total iron binding capacity, and ferritin (to exclude iron deficiency) 1
• Lactate dehydrogenase 1
• Bilirubin and haptoglobin (to exclude hemolysis) 1

Serum Erythropoietin

• Measure prior to RBC transfusion (helps guide treatment decisions regarding erythropoiesis-stimulating agents) 1

Mandatory Bone Marrow Evaluation

All patients with suspected MDS require bone marrow examination 1

Bone Marrow Aspirate

• Morphologic evaluation of dysplasia in erythroid, myeloid, and megakaryocytic lineages (≥10% dysplastic cells required for diagnosis) 1
• Blast enumeration (critical for classification; count at least 500 cells including 100 erythroblasts and 30 megakaryocytes) 1
• Iron stain (Prussian blue/Perls stain) to identify ring sideroblasts (≥15% defines MDS-RS) 1

Bone Marrow Biopsy

• Assessment of cellularity, fibrosis, and topography 1
• Evaluation of megakaryocytic dysplasia (often better visualized on biopsy than aspirate) 1

Cytogenetic Analysis

• Conventional karyotyping of bone marrow aspirate with at least 20 analyzable metaphases 1
• Mandatory for all patients as it provides presumptive evidence of MDS even without definitive morphologic features and is essential for prognostic assessment 1, 2
• Specific MDS-associated abnormalities include: del(5q), monosomy 7 or del(7q), trisomy 8, del(20q), i(17q), del(12p), del(11q), del(13q), del(9q), inv(3)(q21q26.2) 1

Viral Serology

• Anti-HIV testing 1
• Anti-parvovirus B19 (especially in hypoplastic MDS) 1
• Cytomegalovirus testing 1
• Hepatitis B antigen and anti-hepatitis C virus (in transfusion-dependent patients) 1

Recommended Additional Testing

Flow Cytometry

• Evaluation for paroxysmal nocturnal hemoglobinuria (PNH) clone 1
• Assessment for large granular lymphocytic (LGL) disease 1
• Immunophenotyping of myeloid lineages (can detect abnormalities in erythroid, immature myeloid, maturing granulocytes, and monocytes) 1

Molecular/Genetic Testing

• Consider in patients with familial cytopenias to assess for inherited bone marrow failure syndromes 1
• Evaluation for copper deficiency 1
• JAK2 mutation testing in patients with thrombocytosis 1
• For CMML patients: evaluate for 5q31-33 translocations and/or PDGFRB gene rearrangements 1
• HLA-DR15 typing (may predict response to immunosuppressive therapy) 1

FISH Analysis

• If conventional cytogenetics repeatedly fails (absent or poor-quality metaphases), FISH can detect targeted chromosomal abnormalities in interphase nuclei 1

HLA Typing

• For patients requiring platelet support 1
• For potential allogeneic stem cell transplant candidates: full HLA typing (A, B, C, DR, DQ) of patient and potential donors 1

Critical Diagnostic Pitfalls

When Diagnosis is Uncertain

If only unilineage dysplasia is present, no increase in blasts, ring sideroblasts <15%, and no recurrent cytogenetic abnormalities, observe for 6 months with repeat bone marrow examination before confirming MDS diagnosis 1. These patients typically have mild cytopenia only and rapid progression is unlikely 1.

Repeated Bone Marrow Examinations

May be required weeks, months, or even years apart to establish diagnosis and identify patients with rapid disease progression 1

Referral Requirement

All newly diagnosed patients should be evaluated at a center with specific hematologic competence to provide comprehensive diagnostic approach 1

Blast Counting Method

Count blasts as percentage of all nucleated bone marrow cells (not just nonerythroid cells per older criteria), which affects classification boundaries between MDS and AML 1