Blood Cell Morphology

Discocytes

RBCs with a round, biconcave shape that allows for flexibility and optimal gas exchange.

Acanthocytes

RBC with irregular, spiky projections; seen in liver disease, abetalipoproteinemia.

Bite cells

RBCs with a "bite-like" removal of hemoglobin; formed when spleen removes Heinz bodies; associated with G6PD deficiency.

Blister cells

RBCs with a vacuole or blister-like appearance, often a precursor to bite cells. Seen in oxidant damage.

Elliptocytes

Oval or elongated RBCs; seen in hereditary elliptocytosis and iron deficiency anemia.

Megalocytes

Large, oval-shaped RBCs; common in megaloblastic anemias (e.g., B12 or folate deficiency).

Echinocytes (burr cells)

RBCs with short, evenly spaced projections; reversible and may be artifact, but also seen in uremia or pyruvate kinase deficiency.

Schizocytes

Fragmented RBCs; typically from mechanical damage (e.g., DIC, TTP, HUS).

Drepanocytes

Crescent- or sickle-shaped RBCs due to polymerization of hemoglobin S; hallmark of sickle cell disease.

Stomatocytes

RBCs with a mouth-like (slit-shaped) central pallor; associated with hereditary stomatocytosis or liver disease.

Spherocytes

Small, round RBCs lacking central pallor; seen in hereditary spherocytosis or autoimmune hemolytic anemia.

Dacryocytes

Tear-shaped RBCs; seen in myelofibrosis, thalassemia, or marrow infiltration.

Codocytes

RBCs with a central bullseye appearance; seen in liver disease, thalassemia, and hemoglobinopathies.

Neutrophils

Most abundant WBC. Segmented nucleus. First responders in bacterial infection; phagocytose pathogens.

Lymphocytes

Second most common WBC. Includes B and T cells; central to adaptive immunity (antibody production and cytotoxic response).

Monocytes

Largest WBC. Kidney-shaped nucleus; differentiate into macrophages in tissues and help in phagocytosis and antigen presentation.

Eosinophils

Bilobed nucleus; involved in allergic reactions and parasitic infections. Contain granules with cytotoxic proteins.

Basophils

Least common WBC. Involved in allergic and inflammatory responses; release histamine and heparin.