CBC
Marked normo or macrocytic anemia
Leukopenia, commonly with abnormal neutrophil morphology
Thrombocytopenia
Peripheral smear
Type and screen
Infectious workup, if signs of infection present
Evaluate for other causes of symptoms
Marked normo or macrocytic anemia
Leukopenia, commonly with abnormal neutrophil morphology
Thrombocytopenia
Myelodysplastic syndrome
Acute leukemia, infiltrative malignancy 
Acute myeloid leukemia
Myelodysplastic syndrome, myelofibrosis
Leukemoid Reaction
Aplastic anemia
Chronic myeloid leukemia
Paroxysmal nocturnal hemoglobinuria