Table 1. Differential diagnoses in myelodysplastic syndrome and appropriate diagnostic tests for identifying myelodysplastic syndromes.

Differential diagnosis	Diagnostic tests
Aplastic anemia, pure red cell aplasia (PRCA)	Histology, cytology, parvovirus B19
Toxic bone marrow injury (alcohol, lead, NSAR, etc.)	History, lab tests
Reactive bone marrow changes (sepsis, HIV, chronic infections, Tbc, autoimmune diseases etc.), copper deficiency	Cytology, history, lab tests
Monocytosis of other etiology	History, lab tests, molecular genetic testing
Paroxysmal nocturnal hemoglobinuria (PNH)	Immunophenotyping
Immune thrombocytopenia	History, course
Megaloblastic anemia	Vitamin B12/folic acid concentration
Hypersplenic syndromes	History/clinical features (splenomegaly)
Acute leukemia (especially erythroleukemia, FAB-M6)	Cytology, genetic and molecular genetic testing
Myeloproliferative diseases (especially aCML, PMF)	Histology, cytogenetic and molecular genetic testing
Hairy cell leukemia, LGL	Cytology, immunophenotyping, molecular genetic testing (braf, stat3), T-cell receptor
Congenital dyserythropoietic anemia (rare)	Moleculargenetic (sec23b und cdan-1)

NSAR, nonsteroidal antirheumatics; Tbc, tuberculosis; aCML, atypical chronic myeloid leukemia; PMF, primary myelofibrosis; LGL, large granular lymphoma