 Separates into three components: › Red Blood Cells (RBC’s) › White Blood Cells and platelets (buffy coat) › Plasma  Bottom 1/3 to ½ of tube contains the heaviest of cellular material (the RBC’s).

 The blood film is used to perform the differential WBC count; estimate platelet numbers; and evaluate the morphological features of WBCs, RBCs and platelets.  Wedge smears are prepared by placing a small drop of blood on a clean glass microscope slide

 Always stain using the lightest to darkest stain.  Remember which side of your slide is up (clothes pins are marked “top”)  Rinse off from back side of slide  May heat fix to speed up process.

 This is where the different white blood cells are tallied separately. This can be done by a blood counting machine, or by hand.  To manually count the different cells, first you must make a perfect slide. Stain the slide once it is dry.  Using a cell counter you will tally a total of 100 cells (this will make it easy to turn the numbers into a %)

 In the CBC, we determine the number of RBC’s in several different ways. The quickest and easiest is called the hematocrit, also referred to as the packed cell volume (PCV).  The hematocrit or the packed cell volume will tell you if the animal is dehydrated or anemic.

 Whole blood is collected in an anticoagulant, such as EDTA or heparin and place in a capillary tube (75 mm). Microhematocrit tubes should be filled, with one ended plugged with clay sealant

 A blood sample is placed in a tiny glass tube and spun in a centrifuge for 2-5 minutes.  Lie the tube in the centrifuge Hct head with plugged end to the outside, note the number of your slot. Ensure that a balancing hematocrit tube is placed opposite, either by someone placing their tube there, or by adding an empty tube  The cells are heavier than the plasma and are compacted at one end of the tube.

 Special hematocrit tube have a linear scale, so the amount of blood in the tube need to be exact  The bottom of the RBC layer should be at the zero line and the top of the plasma on the top line (page 37 Fig 2-7)  PCV is determined as the percentage of the cellular portion relative to the total amount of blood in the tube

 Plasma color and transparency may be helpful in the determination of a diagnosis and should be recorded  Normal plasma is clear and a pale straw –yellow color  Page 36

 Plasma Protein concentrations estimation by refractometry is is an important component of the CBC in all species  The plasma used to determinate the PCV is collected by breaking the hematocrit tube just above the Buffy coat- plasma interface

 The plasma is allowed to flow onto the refractometer prism.  Page 37 fig 2-9

 Literally means “no blood” but clinically means low total blood hemoglobin.  Absolute anemia: most common, caused by failure to produce adequate numbers of cells or by a loss of cells at a rate greater than can be produced.

 Pale mucous membranes  Exercise intolerance  Tachycardia  Panting  Icterus if anemia is caused by RBC breakdown in bloodstream.

 By RBC size (MCV): › Macrocytic  Erythrocytes are larger than normal.  Usually in the presence of regenerative anemia.  May be seen in FeLv  May see anisocytosis › Normocytic › Microcytic  Cells are smaller than normal which has been determined by Mean Cell Volume (MCV).  Usually occurs with iron deficiency caused by chronic blood loss or parasitism  By Hemoglobin concentration (MCHC) › Hypochromatic  RBC’s have decreased density of the characteristic hemoglobin color.  Frequently observed in iron deficiency caused by chronic blood loss or parasitism. › Normochromatic

 Regenerative anemia: › Characterized by evidence of increased production and delivery of new erythrocytes into circulation. › Usually suggests an extra bone marrow cause (blood loss, hemolysis, etc.)., › Diagnosis:  Peripheral blood smear.  Will see macrocytosis, polychromasia with Wright’s stain, reticulocytosis with methylene blue stain, may also see increased numbers of nucleated RBC’s

 Nonregenerative anemia: › Indicates anemia is result of bone marrow defect. › No response evident in peripheral blood. › Marrow examination may be helpful with the diagnosis.

 Blood Loss Anemia › Results from excessive hemorrhage although source can be subtle. › Must determine if blood loss is internal or external. › Possible causes:  Trauma  Persistent bleeding lesions  Thrombocytopenia  Coagulopathies  Heavy parasitism  Iatrogenic causes

 Acute Blood Loss › Anemia due to loss of blood in a sudden episode. › All RBC parameters are normal for the first 12 hours. › Hypovolemic shock can be apparent prior to a decreased PCV. › Anemia will be normocytic, normochromatic, and apparently unresponsive with a low CRC. › By day 4-5, the retic count increases and the anemia appears responsive.

 Blood is lost slowly and continuously for a period of time.  Body compensates for anemia by lowering oxygen- hemoglobin affinity, preferential shunting of blood to vital organs, increased cardiac output (tachycardia), and increased levels of erythropoietin.  Anemia remains unresponsive unless iron stores are depleted.  With decreasing iron stores, erythropoiesis is limited and RBC’s become smaller and deficient in Hgb (microcytic and hypochromic).  Clinical signs include lethargy, weakness, decrease exercise tolerance, anorexia, pallor, lack of grooming, mild systolic murmur.  Results in iron deficiency

 Result of increased erythrocyte destruction within the body.  Intravascular hemolysis: desctruction of erythrocyctes within the blood vessels and loss of Hgb from the cells.  Extravascular hemolysis: RBC’s are lysed following phagocytosis.

 Can produce anemia through hemolysis  Parasites attach to erythrocyte membrane and cause increased destruction of the cells.  May have symptoms of non-specific weight loss, anorexia, fever, etc.  Babesia  Ehrlichiosis

 Hemoglobin denatures and forms Heinz bodies.  Onion toxicity, Acetaminophen toxicity

 Canine vWD is the most common inherited blood disorder.  Von Willebrand’s Factor promotes platelet clumping in healthy dogs. Lack of this factor will cause a bleeding disorder.  Dobies, German Sheperds, and Labs most common.