RBC Morphology

RBC MorphologyDifferential ListPossible Concurrent ResultsComments

Microcytosis

*Iron-deficiency anemia, portocaval shunt, copper or pyridoxine deficiency, anemia of chronic diseaseDecreased MCV, MCHC

Increased RDW

Hypochromasia

Poorly or non-regenerative

May be normal in Asian dog breeds

Macrocytosis

1. Immature erythrocytes

2. FeLV, myelodysplasia, myeloproliferative disorder

3. Macrocytosis of poodles

4. Hereditary stomatocytosis 1. Regenerative anemia

2.

3. No anemia

Increased MCV

Increased nucleated RBCs

Increased H-J bodies

Hypersegmented neutrophils

4. stomatocytes

Chondrodysplasia in Alaskan malamute

Hypertrophic gastritis in Drentse partrijshond

No clinical disease in miniature schnauzers

3. Probably hereditary, no clinical signs

Polychromasia

1. Extravascular hemolysis

2. Acute Blood loss

3. Hemangiosarcoma

4. Intravascular hemolysis

1. Regenerative anemia

Bilirubinuria

Bilirubinemia

Neutrophilic leukocytosis

2. Regenerative anemia

Decreased PP

Normal morphology

3. Regenrative anemia

Decreased PP

Schistocytes

Acanthocytes

4. Regenerative anemia

Hemoglobinuria

Hemoglobinemia

Agglutination Occurs in liver, spleen, bone marrow

4. Complement mediated,

Bacterialtoxins, Parasites,

Hereditary, Other chemicals/toxins

Hypochromasia

1. Iron-deficiency anemia in dogs1. Increased MCV

Increased RDW

Microcytosis

Keratocytes

Schistocytes

Acanthocyte

1. Hepatic Lipidosis in cats

2. Microangiopathy: hemangiosarcoma, lymphosarcoma of liver/spleen, hematoma 1. Icterus

2. Regenerative anemia

Keratocytes

Schistocytes

Nucleated RBCs

Keratocyte

1. Iron-deficiency anemia

1. Increased MCV

Increased RDW

Microcytosis

Keratocytes

Schistocytes

Schistocyte

1. DIC

2. Vascular neoplasms; hemangiosarcoma

3. Iron-deficiency anemia due to oxidative injury

1. Thrombocytopenia

Regenerative anemia

2. Regenerative anemia

Keratocytes

Acanthocytes

3. Increased MCV

Increased RDW

Microcytosis

Keratocytes

Schistocytes

Echinocytes (Burr cells)

1. Artifact/ crenation

2. Renal disease

3. Lymphoma

4. Rattlesnake bite (type 3)

5. Chemotherapy in dogs

6. Exercise in horses2. Increased BUN, creatinine

decreased urine specific gravity

Spherocyte

1. Immune-mediated hemolytic anemia

2. Mismatched blood transfusion

3. Zinc toxicosis

4. Bee stings

1. Regenerative or pre-regenerative anemia

AgglutinationNot appreciated in in species other than dogs

3. Usually causes Heinz body anemia

Eccentrocyte

(no picture; lopsided-looking cell with most hemoglobin on one side)1. Oxidative damage

2. Glucose-6-dehydrogenase deficiency1. Heinz bodies

2. Heinz bodies

Codocyte/leptocyte aka target cell

Little clinical significance

1. Artifact of excessive EDTA

2. Increased serum cholesterol in dogs

Stomatocyte

1. Hereditary stomatocytosis1. Chondrodysplasia in Alaskan malamute

Hypertrophic gastritis in Drentse partrijshond

No clinical disease in miniature schnauzers

Heinz Bodies

1. Diabetes mellitus in cats

2. Lymphoma

3. Hyperthyroidism

4. Oxidative drugs and compounds

May cause intravascular hemolysis( severe hemolytic anemia if many RBCs are affectedCaused by oxidative denaturation of hemoglobin

4. Onions, garlic, Brassica sp plants, dried or wilted red maple leaves, benzocaine, zinc, copper, acetominophen, propfol, naphthalene, vitamin K, methylene blue, propylene glycol

Basophilic stippling

1. Immature RBCs in ruminants, cats, dogs

2. Lead poisoning1. Regenerative anemia

Howell-Jolly bodies

1. Regenerative anemia

2. splenectomy/ suppressed spleen function1. Reticulocytes/ polychromasia

Increased MCV

Nucleated RBCs

Nucleated RBCs

1. Regenerative anemia

2. Lead poisoning

3. Nonfunctioning spleen/splenectomy

4. Increased corticosteroids

5. Myelodysplasia or myeloproliferative disease in cats1. Reticulocytes/

polychromasia

Increased MCV

Howell-Jolly bodies

2. Increased nucleated RBCs out of proportion with degree of anemia

5. Lack of polychromasia

Siderotic granules/ Pappenheimer bodies

1. Impaired heme synthesis

2. Chloramphenicol therapy

3. Myelodysplasia

4. Ineffective erythropoiesis of unknown cause

Agglutination

1. IMHA

2. Mismatched blood trransfusion1. Regenerative anemia

Spherocytes

Falsely increased MCV

Falsely decreased RBC count

Rouleaux formation

1. gammopathy

2. multiple myeloma1. Increased PP

2. Increased PP

Normal in horses; slight rouleaux normal in dogs and cats

Regenerative Anemia

. Macrocytosis

Increased MCV (not so much in dogs)

Decreased MCHC

Polychromasia

Reticuloytes (not in horses)

Basophilic stippling (ruminants)

Serial increases in MCV (horses)

Increased RDW

Nucleated RBCs

Howell-Jolly bodies

Hypochromasia