Hematology

Hypochromasia Hypochromasia indicates that the red blood cells have less hemoglobin than normal and the term, hypochromasia, is used in two contexts: As a descriptor of red blood cells on a blood smear: Here it refers to the appearance of red blood cells with a thin rim of cytoplasm (due to less hemoglobin) resulting in increased central […]

This section provides information on the specific tests (how they are performed and how we interpret them) that are on a hemogram. Note that we have not included the estimation of total protein by refractometry or an assessment of plasma color, since this is not provided on all hemograms. We have also provided the following

Anaplasma species are intracellular bacteria that are within the family of Anaplasmataceae of the order Rickettsiales. The family of Anaplasmataceae now includes the genera of Ehrlichia, Anaplasma, and Neoricketssia, after renaming of organisms and reclassification in 2001 based on 16S RNA and groESL gene sequences in the bacteria  (Allison and Little, 2013). The names of some species,

Cytauxzoon felis is an apicomplexan protozoal parasite that causes severe, and often fatal disease, in cats. Organisms parasitize erythrocytes and schizonts are found in macrophages in blood and tissues, facilitating diagnosis (for more images of the parasite, including schizonts, see the feline blood and infectious disease albums under the Atlas in the hematology gallery). Epidemiology

Canine Mycoplasma haemocanis (formerly Haemobartonella canis) rarely causes anemia in dogs with normal spleens and normal immune systems. Clinical anemia can develop when a carrier dog is splenectomized or when a splenectomized dog is transfused with blood from a carrier donor. M. haemocanis may be a widespread latent infection in kennel-raised dogs. These dogs are

Babesia and Theileria are protozoal parasites that are different genuses within the phylum Apicomplexa. They have a replicative stage within mammalian RBCs.  Since one of the life stages (sporozoites) replicate asexually (to form merozoites) within RBCs and rupture RBCs to infect other cells, they result in a hemolytic anemia with an intravascular component (hemoglobinemia, hemoglobinuria), helping

Canine Distemper Large aggregates of viral nucleocapsid particles can form in erythrocytes, leukocytes, and epithelial cells in many tissues during the acute phase of infection with Canine distemper virus, resulting in cytoplasmic inclusions visible by light microscopy. Their presence in blood is transient; they are very rarely encountered but are pathognomonic when identified. Shown at

Stain precipitate Stain precipitate usually results from the use of aged staining solutions and/or inadequate rinsing of slides following application of stain. Shown at right is a smear in which large obvious aggregates of stain precipitate are overlying erythrocytes. Notice how the precipitate is in a different plane of focus than are the cells. Finer

Red blood cell inclusions can arise from a variety of sources. Correct identification of these abnormalities is important since it can provide insights into metabolic, physiologic, and pathologic conditions affecting the red blood cells. Basophilic stippling Basophilic stippling represents the spontaneous aggregation of ribosomal RNA in the cytoplasm of erythrocytes. These aggregates stain, and hence

The term “poikilocyte” is a generic or umbrella term to describe erythrocytes with abnormal shape. We can subclassify poikilocytes by specific shape changes, some of which have fairly unique diagnostic significance, while other forms are quite non-specific. Wherever possible, the red blood cell shape should be identified specifically, e.g. acanthocyte, keratocytes, echinocytes, and the generic