WBCs and RBCs

Normal RBCs

Avian RBC

Camelid RBC

Neutrophils

-Most common WBC in all domestic species except ruminants

Eosinophils

-About the same size as a neutrophil

-Absent or present in very low numbers (normal)

Basophils

-Rarely seen in normal blood smears

-Common in equine

-Slightly larger or same size as neutrophil

Lymphocytes

-Most common WBC in ruminants and lab animals

-Smallest of WBCs

-Minimal cytoplasm

Monocytes

-Largest of all WBCs

Platelets (Thrombocytes)

-Fragments of cytoplasm of megakaryocytes in bone marrow

Macro platelet -common in cats

Platelet clump -common in dogs

Rouleaux Formation (abnormal)

-Most common in horses

-May be an artifact of delay, refrigeration, or inflammation

Agglutination (abnormal)

-Antibody coats the RBC surface causing clumping

Anisocytosis (abnormal)

-Variation in RBC size

Hypochromic (abnormal)

-Increased central pallor and less heme

Torocyte (abnormal)

-Normal color but middle of cell is absent

Poikilocytosis (abnormal)

-Variation in cell shape

-Common in healthy goats and neonate ruminants

Echinocytes (abnormal)

-Crenated RBCs

-Surrounding solution is hypertonic

-Most common shape variation of RBCs

Acanthocytes (abnormal)

-Projections over entire surface

-Associated with liver and kidney disease and rattlesnake bites in dogs

Stomatocytes (abnormal)

-Elongated, often curved, central pale area resembling a mouth

Knizocytes (abnormal)

-Bar cells

-Darker staining central area which extends across cell with pale on either side

Codocytes (abnormal)

-Target cells

-Thicker, darker staining center surrounded by lighter staining area and dark periphery

Spherocytes (abnormal)

-Thickened/rounded, smaller, darker staining (hyperchromic)

-Seen with autoimmune diseases and splenic disorders

Schistocyte (abnormal)

-irregular RBC fragment due to mechanical damage to cell membrane

Keratocyte (abnormal)

-Helmet cell

-RBC with portion removed

Ovalocyte/Elliptocyte

-Oval shaped RBC

-Normal for camelids

-Nucleated forms in birds, fish, amphibians, reptiles

Dacryocyte (abnormal)

-Teardrop shaped RBC

Fusocyte/Accuminocyte (abnormal)

-Spindle shaped that tapers to a point at both ends

Drepanocyte (abnormal)

-Sickle cell

-Elongated, thread-like cell

-Seen in deer (cervids)

Nucleated RBC (abnormal)

-Anemia (increased RBCs from bone marrow due to increased destruction or loss of RBC in circulation)

Reticulocytes

-Immature RBCs

-Polychromic and macrocytic

-Dark stain: NMB; Bluish stain: Diff Quik

-Cats: Aggregate and Punctate

Howell-Jolly Body

-Stains well with Diff Quik

-Small retained portion of nucleus

Heinz Body

-Stains well with NMB

-Small, round, refractile denatured hemoglobin that is bright and colorless with slightly darkened edges

-Single or multiple within the cell or surface

Basophilic stippling

-Stains well with Diff Quik

-Sometimes seen secondary to regenerative bone marrow response to anemia

-Heavy metal toxicity (lead poisoning)