Laboratory Procedures for Veterinary Technicians Review

Hematopoiesis

The prodution of blood cells and platelets

Whole Blood

Composed of plasma and cells

Plasma

Fluid portion of whole blood. The liquid remaining when clotting is prevented with an anticoagulant

Cells

RBCs, WBCs, and thrombocytes

Erythrocytes (RBCs)

Contain hemoglobin to carry oxygen. Primary job is delivering oxygen to cells and tissues. Last for about 1 month in circulation

Thrombocytes (Platelets)

Involved in blood clotting. Along with circulating proteins, they form clot after initial injury

Leukocytes (WBCs)

Part of the immune system

Complete Blood Count (CBC)

Cells most commonly evaluated using ____. A routine test providing information about blood cell types. Can also indirectly assess bone marrow health

Erythropoiesis

Production of erythrocytes

Leukopoiesis

Production of leukocytes

Thrombopoiesis

Production of thrombocytes. Platelets are produced from megakaryocytes and form the first stage of coagulation when a blood vessel is damaged. Influenced by the hormone Thrombopoietin. Fibrin forms in the presence of aggregated platelets, leading to clot formation. Fibrin clot is needed for effective hemostasis at injury sites.

Kidneys

Secrete hormone erythropoietin. RBC production is regulated by the hormone erythropoietin, which is released as needed

Spleen

Stores extra RBCs

Erythroproietin (EPO)

Cytokine responsible for production of RBCs. Triggers the process of Erythropoiesis

EPO Process

Tissues that lack oxygen due to low red bloods. The kidneys secrete more EPO in response. EPO stimulates bone marrow to make more red blood cells. Kidneys detect an increase in hemoglobin, a key protein in red blood cells, and will secrete less EPO in response

Oxygen Saturation

Percentage of available hemoglobin that is carrying oxygen

Hematopoietic Stem Cells

Specialized cells that reside within the bone marrow and have the ability to generate all types of blood cells. Essential for maintaining a healthy blood. Can increase their production of specific blood cell types to meet the body’s needs.

Rubriblasts (RB)

Also known as pronormoblast, is the earliest form seen in peripheral blood have a large nucleus and nucleoli is prominent

Prorubricyte

Cytoplasm still present, moderate nucleus seen, smaller than rubriblasts.

Rubricyte

Smaller nucleus, no nucleoli present. Basiophilc cytoplasm clumping seen

Metarubricyte (MR)

Small cells, condensed nucleus, hemoglobin formation is complete

Reticulocyte

Immature RBC, usually released by the bone marrow when the body senses anemia.

Polychromatic Rubricyte

PR

Progranulocyte

PG

Mature Neutrophil

MN

Thrombocytosis

High numbers of platelets

Thrombopenia

Low numbers of platelets

Granulocytes

Granules: Neutrophils, Eosinophils, Basophils

B Cells/B Lymphocytes

Responsible for antibody responses. Produce antibodies

T Cells/T Lymphocytes

Responsible for cell mediated immune response. Produce chemicals to stimulate immune reaction

-penia

Decreased number of cells

Neutropenia

Decreased neutrophils

Pancytopenia

Decrease of all blood cell types

-philia

Increased number of cells

Left-Shift

Increased numbers of immature neutrophils

Leukemia

Neoplastic cells of blood or marrow

Leukemoid Response

Mistaken for leukemia . Marked leukocytosis, usually inflammatory disease

Myeloblast

Cells differentiate into neutrophils, basophils, eosinophils, and monocytes after this stage

Phagocytosis

Chase and engulf bacteria

Neutrophil

First line of defense. Chase and engulf bacteria. Live only 6 hours in circulation. Most numerous in blood. Segmented nucleus in mature cell. Immature lack segments. Most common type of cell. Primarily involved in fighting bacterial infections

Lymphocyte

Three types. Impossible to differentiate types on blood smear. Primarily found in lymph nodes. Live weeks to month. Second most common cell. Important for immune response and antibody production

Monocyte

Live about 24 hours. Mature into macrophages in tissue. Third most common type of blood. Precursors to macrophages that engulf cellular debris and foreign material

Eosinophil

Respond to chronic allergens and parasitism. De-granulate to alert the immune system. Live about 1 week. Very low number of cells. Play a role in allergic reactions and parasitic infections

Basophil

Produce immediate allergic response. De-granulate to produce heparin and histamine. Live about 3 days. Very low in number or absent. Involved in allergic reactions and inflammation

Liver

Manufactures proteins

Albumin

Maintains oncotic pressure

Globulin

Anitbodies

Fibrinogen

Clotting

RBC

Number of red blood cells. The iron in hemoglobin is what gives it its color. In stained filmed, mature ones appear circular with a lighter, central area called the central parlor. Hypochromic have less color than normal, due to a reduction in hemoglobin. Hyperchromic have more color than normal, often due to an increase in hemoglobin

HCB

Volume of hemoglobin present. Direct relationship to RBC numbers

HCT

Percentage of red blood cells to plasma. Close to or the same as PCVP

Absolute

RBC volume changes

Relative

Plasma volume changes

RETIC

number of reticulocytes

% RETIC

Percentage of erythrocytes that are reticulocytes

Mean Corpuscular Volume (MCV)

Average volume of RBC. Normocytic, microcytic, macrocytic

Red Blood Cell Distribution Width (RDW)

Variation in volume of RBC

Mean Corpuscular Hemoglobin (MCH)

Average amount of hemoglobin per RBC

Mean Corpuscular Hemoglobin Concentration (MCHC)

Average concentration of hemoglobin per RBC

PLT

Number of platelets

Plateletcrit (PCT)

Mass of platelets in relation to blood. Not commonly used. Measure of the percentage of total blood volume that is made up of platelets

Platelet Distribution Width (PDW)

Variation in volume of platelet

Mean Platelet Volume (MPV)

Mathematical average size of individual platelets counted by an analyzer. Increased may be seen in loss, destruction or consumption of platelets but accompanied by megakaryocytic hyperplasia.

Hematology

The study of the numbers and morphology of blood cellular elements

Blood Collection

A fundamental part of veterinary practice. Procedure should be performed aseptically. Aim for a clean stick to avoid sample hemolysis. Gently withdraw blood to minimize cell damage. Minimize disturbance and discomfort to the animal

Jugular Vein, Peripheral Vein

Preferred sites for small animals

Jugular Vein

Preferred sites for horses

Jugular Vein, Tail Vein

Preferred sites for cattle

Jugular, Brachial Artery, Pedal Artery

Preferred sites for bird

Tail Vein

Preferred sites for pocket pets

Ethylenediaminetetraacetic Acid (EDTA)

Purple top. Used for hematology and cytology on body cavity fluids. Prevents clotting. Requires proper filling to avoid cell artifacts. Avoid shaking after collection. Generally preferred for non-mammalian hematology. The blood of certain species of birds, such as cranes, and reptiles, such as turtles, can hemolyze upon contact with EDTA. When hemolysis occurs in these specific non-mammalian species due to EDTA, it invalidates the packed cell volume (PCV) and negatively impacts the assessment of red blood cell morphology during blood smear examination. The preferred anticoagulant

Heparin

Green Top. Yields plasma for biochemistry. Can be used for some hematology tests. Heparin tubes should be more than half full for chemistry. Typically ran in house

Sodium Citrate

Blue top. Used for obtaining plasma for coagulation panel testing. Tests that assess how well the blood clots and involve measurements like prothrombin time (PT), Activated partial thromboplastin time (aPTT), and quantitative fibrinogen assay (QFA). Used for non-mammalian hematology if EDTA causes hemolysis, maintain correct blood: citrate ratio. The preferred anticoagulant

Gel or Clot Activator

Red-top or tiger top. Primarily used for collecting blood samples for serum separation. Promotes blood clotting and facilitates the separation of serum from the blood cells after centrifugation

Chemistry Panels

Assess various aspects of an animal’s health, including kidney function, liver function, electrolyte balance, and more

Serum

Does not contain fibrinogen or other clotting factors because they are removed during the clotting process. Often preferred for chemistry, serology, and immunology tests

Packed Cell Volume (PCV)

Measures the percentage of red blood cells in the blood

Total Protein (TP)

Measures the total amount of protein in the plasma

Anemia

A deficiency in red blood cells

Normal PCV/TP

Indicates the patient is likely well-hydrated and has a normal red blood cell volume

Elevated PCV/TP

Indicates dehydration

Low PCV

Indicates anemia

35-55%

Dogs PCV

25-45%

Cats PCV

Clear or Straw

Normal serum/plasma

Icteric

Yellow serum/plasma

Lipemic

Strawberry milk colored serum/plasma

Hemolyzed

Dark red serum/plasma

Diff-Quik

A type of rapid Romanowsky-type stain used for preparing blood smears for microscopic evaluation

Anisocytosis

Indicates that there is a variation in the size of red blood cells within a sample

Microcytosis

Refers to red bloods cells that are smaller than normal

Macrocytosis

Refers to red blood cells that are larger than normal

Poikilocytosis

Abnormally shaped

Acanthocytes

Characterized by irregular, spiky projections. Commonly seen in liver disease. Spur cells. Seen in altered lipid metabolism. Hepatic lipidosis in cats. Hemangiosarcoma in dogs

Schistocytes

Result from damage or fragmention of red blood cells

Echinocytes

Have many small rounded protrusions. Distributed evenly through the cell. Can occur if EDTA tube in underfilled. Seen in renal disease, lymphosarcoma, snake bite

Nucleated Red Blood Cells (NRBC)

Immature red blood cells that still retain a nucleus. Normally found in the bone marrow and are not typically present in healthy adult peripheral blood

Spherocytes

Small, spherical, dense RBC’s. Lack Central pallor. Partially eaten

Stomatocytes

Open or smiling mouth at the pallor. RBC membrane defect. Can be artifact

Schistocytes

Fragmented RBCs as a result of membrane damage. Have a helmet, horned, or crescent appearance. Occur due to trauma in blood vessels