Smear findings	Possible diagnosis	Comments
Atypical lymphocytosis	Viral infection (e.g., Epstein-Barr virus, cytomegalovirus)	Abundant cytoplasm
Basophilic stippling	Thalassemia, chronic alcohol use, lead or metal poisoning	Ribosomal precipitate (appears as blue granules) throughout the cytoplasm of the red blood cell
Cryoglobulin	Cryoglobulinemia, mycoplasma pneumonia, multiple myeloma, some autoimmune disorders	Proteins that precipitate when blood is below normal body temperature
Giant platelets	Congenital thrombocytopenias, immune thrombocytopenic purpura	Caused by increased platelet turnover or release of immature forms into the circulation
Megakaryocyte fragments	Myelofibrosis	Presence of large platelets
Nucleated red blood cells	Severe hemolysis, myelofibrosis	Immature red blood cells secondary to accelerated erythropoiesis
Oval macrocytosis	Vitamin B12 and folate deficiencies	Suggests impaired bone marrow synthesis
Platelet agglutination	Pseudothrombocytopenia	Clumping of platelets in patients with EDTA-activated antiplatelet antibodies
Platelet hypogranularity	Myelodysplastic syndrome, myelofibrosis	Suggests impaired bone marrow synthesis
Round macrocytosis	Myelodysplastic syndrome, myelofibrosis, chronic liver disease	Suggests impaired bone marrow synthesis
Schistocytosis	Thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, disseminated intravascular coagulation, defective prosthetic heart valve	Fragmented erythrocytes
Target cells	Chronic liver disease, hemoglobinopathies	Excess hemoglobin in the center of the red blood cell