Abnormalities in Erythrocytes

Laboratory Procedures

Polychromasia:__________________________________________________________________________

Anisocytosis:____________________________________________________________________________

Poikilocytosis:___________________________________________________________________________

Remember These????

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.)

Polychromasia

Is a decrease in color, due to a decreased staining intensity caused by insufficient hemoglobin within the cell.

Most commonly caused by Iron Deficiency

Hypochromasia

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

Hyperchromasia

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)

MCHC

Variations in Size

Can indicate Anemia

Classified by Macrocytosis OR Microcytosis

Anisocytosis

Simply means that there are an abnormal amount of cells larger than normal size.

Can indicate liver disease or Vitamin B12 deficiency.

Macrocytosis

Indicates that there is an abnormal amount of cells that are smaller than normal.

Can indicate iron deficiency.

Microcytosis

Stands for Mean Corpuscular Volume Describes cells as being Normocytic,

Microcytic, or Macrocytic.

Measures the average volume of RBC’s.

Normal values are 66-77 fL (femtolitres)

MCV

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.

Poikilocytosis

All of the following cells are under the “umbrella” of Poikilocytes. They just have different names!

(Remember rule #2)

Many Poikilocytes

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.

Schistocytes

Acanthocytes (Spur Cells)

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.

Acanthocytes Continued

Echinoctyes (Burr Cell) Echinocytes have multiple, small, delicate

regular shaped spines evenly distributed around the cell and are indistinguishable from artificially crenated cells.

Echinoctyes Continued

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.

Drepanocytes (Sickle cell) 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.

Drepanocytes

Prekeratocytes Cells with pseudovacuoles are called blister

cells or pre-keratocytes.

Keratocyte (Helmet Cells) 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

Codocytes (aka Leptocytes)

Stomatocytes 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.

Target Cells (Bull’s Eye Cells) Thin, bell-shaped cells

Centrally stained area

Can indicate liver disease or hemoglobinopathies.

May be seen asartifacts when smearsmade in high humidity or if blown dry.

Target Cells

Dacryocytes (tear drop cells)

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’s) 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.

Heinz Bodies

Reticulocytes 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.