Laboratory Procedures

 Polychromasia:______________________________ ____________________________________________  Anisocytosis:________________________________ ____________________________________________  Poikilocytosis:_______________________________ ____________________________________________

 Can exist as Hypochromasia or Hyperchromasia.  Polychromatic erythrocytes exhibit a bluish tint. This is caused by a small amount of nucleus retained in the cytoplasm. These may appear as a Reticulocyte. (We will talk about these later in this presentation.)

 Is a decrease in color, due to a decreased staining intensity caused by insufficient hemoglobin within the cell.  Most commonly caused by Iron Deficiency

 Refers to a cell that appears darker than normal cells. This gives the appearance that the cell is over-saturated with hemoglobin.  TRUE hyperchromasia cannot exist!  Each erythrocyte has a fixed capacity for hemoglobin and over-saturation cannot occur

 Stands for: Mean Corpuscular Hemoglobin Concentration  Describes cells as normochromatic or hypochromatic  Normal MCHC is 31-36%  (You will learn this calculation in Clin. Path)

 Variations in Size  Can indicate Anemia  Classified by Macrocytosis OR Microcytosis

 Simply means that there are an abnormal amount of cells larger than normal size.  Can indicate liver disease or Vitamin B12 deficiency.

 Indicates that there is an abnormal amount of cells that are smaller than normal.  Can indicate iron deficiency.

 Stands for Mean Corpuscular Volume  Describes cells as being Normocytic, Microcytic, or Macrocytic.  Measures the average volume of RBC’s.  Normal values are fL (femtolitres)

 Is a major deviation in the normal shape of the erythrocyte.  Remember that this term is an umbrella term for abnormally shaped erythrocytes, and should not be used as a diagnosis.

 All of the following cells are under the “umbrella” of Poikilocytes. They just have different names!  (Remember rule #2)

Schistocytes (Fragmented Cells)  RBC’s with abnormal shape.  Formed as a result of shearing of the cell by fibrin strands. This occurs when red blood cells rapidly pass through microvasculature that is lined or meshed with strands.  They are observed in fragmentation hemolysis caused by DIC, vascular neoplasia, endocarditis, and possibly iron deficiency anemia.

 The term acanthocyte is derived from the Greek word “acanthi” meaning “thorn” Acanthocytes are cells with five to ten irregular, blunt, finger-like projections.  The projections with vary in width, length and surface distribution.  These cells are seen in animals with altered __________metabolism such as cats with ____________________________or dogs with ________________disease.

 Echinocytes have multiple, small, delicate regular shaped spines evenly distributed around the cell and are indistinguishable from artificially crenated cells.

 Echinocyte formation can be artificial, often seen with slow drying blood films or if the EDTA tube was underfilled. This artifact is then termed crenation.  Echinocytes have been associated with renal disease, lymphosarcoma and rattlesnake bites in dogs.  They can been seen after exercise in horses.

Crenation  Identified as the presence of many irregular membrane projections involving most RBC’s.  It is usually an artifact due to slow drying of the blood film.  Commonly observed in pig blood but can be seen in any species.

 These cells are crescent shaped with pointed ends.  Drepanocytes are often seen in normal blood of deer and goats. It is thought to be a result of low oxygen tension.

 Cells with pseudovacuoles are called blister cells or pre-keratocytes.

 Also called bite cells. Keratocytes are associated with trauma especially cellular damage from contact with fibrin strands.

Spherocytes  Cells have a spheroid shape instead of the usual biconcave disk shape.  Have reduced cell membrane and are hyperchromatic.  Seen most frequently in autoimmune hemolytic anemia (AIHA).  Usually seen in dogs.

 Is an “umbrella term” describing cells that are characterized by an increase in membrane surface area.  Include the following: ◦ Stomatocyte ◦ Target Cells

 The appearance of stomatocytes with their oval or rectangular central pallor has been compared to a smiling face, a fish mouth, and a coin slot.  Stomatocytes are associated with a hereditary condition but are also seen in liver disease, acute alcoholism (humans), and electrolyte imbalances.

Stomatocytes

Target Cells  Observed mainly in dogs.  Represent cells with an increased membrane- to-volume ratio not specific to any disease.  The cell membrane is thin and flimsy.

 Thin, bell-shaped cells  Centrally stained area  Can indicate liver disease or hemoglobinopathies.  May be seen as artifacts when smears made in high humidity or if blown dry.

 These tear drop shaped cells are seen in myeloproliferative diseases.  These cells, when produced as an artifact can be identified by the direction of their tail.

 Dacryocytes produced as an artifact have their tails pointing in the same direction.

 Nucleated red blood cells (NRBC) usually represent early release of immature red blood cells during anemia.  These are nuclear remnants seen in young erythrocytes during a response to anemia.

Basophilic Stippling  Observed in RBC’s that contain abnormal aggregation of RNA.  Can be observed in cases of heavy metal poisoning with non-regenerative anemias or intense erythrogenesis in dogs, cats, and ruminants.

Howell-Jolly Bodies  Nuclear remnants observed in young erythrocytes.  Often observed in cats and horses.  Can be seen in regenerative anemic animals.  Also may be seen with splenic disease or in an animal with the spleen removed.

Heinz Bodies  Particles of denature hemoglobin protien.  They stain with new methylene blue and appear as colorless bumps with quick stain.  May be caused by oxidant drugs and chemicals. Also associated with onion toxicity in dogs!  Normal cat blood may have 2-3%.  Spleen recognizes as abnormal and starts to lyse the cells.

 These are immature red blood cells that contain organelles (ribosomes) that are lost in the mature cell. Cats have two forms of reticulocytes. ◦ The aggregate form contains large clumps of reticulum. They mature into the punctate form within 24 hours. ◦ The punctate form, unique to cats, contains two to eight singular granules. Punctate reticulocytes circulate for 7-10 days before the all the ribosomes are lost.

Reticulocytes in the Peripheral Blood  Non-nucleated cell containing RNA which can be easily seen when stained with methylene blue.  Hallmark of erythrocyte regenerative response.