Veterinary Hematology

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Veterinary Hematology

• - An introduction

Gittan Gröndahl, DVM, PhD
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What Is Blood, and How Much Blood Is There?
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What Is Blood, and How Much Blood Is There?
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Red Blood Cells The Oxygen Carriers
Hemoglobin
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Red Blood Cells The Oxygen Carriers
Hypoxia
Erythropoeitin (EPO)
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Red Blood Cells Measurements
Hemoglobin
Hematocrit / PCV
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Red Blood Cells Physiological Alterations
HGB RBC HCT
growing animals...
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Red Blood Cells Physiological Alterations
HGB RBC HCT ???
exercise, fear, stress...
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Red Blood Cells Physiological Alterations
dehydration, shock, high altitude, chronic lung
disease, anabolic steroids...
HGB RBC HCT ???
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Red Blood Cells Physiological Alterations
anaemia, anaesthesia, sedation, late pregnancy...
HGB RBC HCT ???
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Red Blood Cells Artefactual Alterations
hemolysis, too little blood, extended storage
in EDTA...
HCT ???
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Red Blood Cells Regenerative Signs
Reticulocytes
If HCT lt30 (dog) or lt20 (cat) ? count
reticulocytes
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Red Blood Cells Regenerative Signs
Reticulocytes never in horses!
Not even seen in regenerative anemia in
horses Instead, macrocytes are released RDW
? MCV ?
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Red Blood Cells Regenerative Signs
Nucleated RBC
Anisocytosis greater variation in cell size, RDW
?
Polychromasia variable coloration
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Red Blood Cells Regenerative Signs
Howell-Jolly bodies nuclear remnants
Basophilic punctuation
Macrocytosis large cells, MCV ?
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So What Is This?
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Red Blood Cells Number and size in mammals
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Red Blood Cells Mean Cell Volume (MCV)
Used in classification of anemias
Macrocytosis - MCV ? Often in regenerative anemia
Microcytosis - MCV ? Often sign of iron
deficiency, such as chronic blood loss
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Red Blood Cells MCHC, Mean Cell HGB
Concentration
Used in classification of anemias
Normochromic - MCHC normal
Hypochromic - MCHC ? In acute and chronic blood
loss, hemolytic anemia or iron deficiency
(Hyperchromic - MCHC ? ) Artefact!
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Blood Groups in Animals
All animals species have their specific blood
group system.
1. Blood transfusions 2. Incompatibility between
dam and offspring
Cross-matching!
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Anemia Too Low Oxygen Carriage Capacity
Signs of anemia
Pale in eye and mouth Vigor and strength
? Appetite ? Heart rate ? Respiratory rate
? Laboured breath Blood, bleedings,
hematomas Icterus
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Anemia General Causes
1. Blood loss (regenerative anemia) Coagulopathies
Gastrointestinal hemorrhage Platelet
disorders Splenic rupture Trauma/surgery
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Anemia General Causes
2. Blood destruction / hemolysis (regenerative
anemia) Fragmentation Immune-mediated
disease Infections Intrinsic RBC
defects Toxicities
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Anemia General Causes
3. Decreased / ineffective production of RBC
(non-regenerative anemia) Anemia of inflammatory
disease Aplastic or hypoplastic anemias Metabolic
or endocrine disease Neoplastic
disease Nutritional deficiency anemias (e.g.,
iron, copper, folate, cobalt)
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Platelets The Sealers and Healers
First line of defense in damage to vessels
Important in inflammation and wound healing
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Platelets Thrombocytopenia PLT ?
Caused by
Production ? Destruction ? Consumption ?
Signs, if PLT lt20-50 x 109/L Hematomas Bleedings
horse
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Platelets Thrombocytopenia PLT ?
Certain medications (antibiotics, NSAID,
hormones) Some infections (FIV, FeLV, BVDV,
EIA, Ehrlichia etc) Hemolytic anemia DIC
Disseminated intravascular coagulation Vaccination
Malignant cells
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Platelets Thrombocytopenia PLT ?
False Low PLT Caused by
Platelet aggregates
Platelets and fibrin clumps
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Platelets Thrombocytosis PLT ?
Caused by
Surgery or trauma Chronic bleedings Acute/chronic
infections or inflammatory conditions Cushings
disease Corticosteroid therapy Myeloproliferative
disorders
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White Blood Cells The defence troops
Defence Cleaning up Inflammatory reactions
Signalling system Cytokines Receptors
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White Blood Cells The defence troops
First line of defence Phagocytosis
Antibodies Cell destruction
Toxic proteins Parasites Allergic reactions
Interplay Phagocytosis
Allergic reactions Histamin, heparin
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White Blood Cells Physiological Alterations
breed, sex...
WBC ??/ ??
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White Blood Cells Physiological Alterations
late pregnancy, feeding...
young animals...
WBC ???
exercise, stress, excitation...
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White Blood Cells Artefactual Alterations
extended storage...
WBC ???
Cells from very sick animals are the most
sensitive
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Granulocytes Neutrophils
White, small pink granules
White, no granules
White, small stronger pink granules
White/pink, no granules, knobby nuclei
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Granulocytes Band Neutrophils
Bands Left Shift
Regenerative left shift Neutrophilia with gt1,0 x
109/L of Bands for dogs and catsgt0,3 x 109/ L of
Bands for horses and cattle
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Granulocytes Band Neutrophils
Bands Left Shift
Poor Prognosis!
Degenerative left shift Normal or Low WBC count
with significant left shift or Band neutrophils
Segmented neutrophils (with any WBC count)
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Granulocytes Toxic Neutrophils
Guarded Prognosis!
Basophilic discoloration, foaming, Döhle bodies,
toxic granules
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Granulocytes Eosinophils
Small rod-shaped orange granules
Very large globular orange granules
Many small round orange granules
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Granulocytes Basophils
Small oval granules, pale lavender. Rare.
No granules, ribbon-like nucleus, gray-lavender.
Rare.
Small deep purple granules. Low numbers.
Small deep purple granules. Low numbers.
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Lymphocytes
Small, dense chromatin
Small, dense chromatin
Quite variable
Slightly larger
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Lymphocytes -Reactive and Granular
Reactive lymphocytes
Granular lymphocytes
Small pink granules
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Monocytes
Extremely variable in appearance in all animals
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Avian Hemogram
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Dogs Hemogram
Excitement (adrenaline epinephrine) Not so much
change All cells (?)
Inflammation WBC ??? Left shift if gt1 x 109/L
bands Neutro ??? (10-30)
Stress (cortico-steroids) WBC ?? Neutro ?? No
left shift Lymph ? Eos ? Mono ?
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Cats Hemogram
Stress (cortico-steroids) WBC ?? Neutro ?? No
left shift Lymph N/? Eos ?
Excitement (adrenaline epinephrine) Common
reaction Lymph ??
Inflammation WBC ??? (25-40) Left shift if gt1 x
109/L bands Neutro ???
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Horses Hemogram
Stress (cortico-steroids) WBC ?? (-20) Neutro
?? No left shift Lymph N/?
Excitement (adrenaline epinephrine) Common
reaction WBC ?? (12-15) No left shift Lymph ??
(6-14)
Inflammation WBC ?? Left shift if gt0.3 x109/L
bands Neutro ?? (10-20) Severe infectionsWBC
?? Neutro ?? degenerative left shift toxic
changes
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Cattles Hemogram
Inflammation Acute WBC N/? Marked left shift
(gt0.3 x109/L bands) Chronic WBC ?? (20) Neutro
?? Left shift
Stress (cortico-steroids) WBC N/? No left
shift Lymph ? Eos ?
Excitement (adrenaline epinephrine) WBC ??
(15-27) No left shift Lymph N
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WBC- General Interpretation
Repeated analyses -gt Best for assessment of

• pathological conditions
• duration
• prognosis

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WBC- General Interpretation

• neutrophils ?
• mild left shift
• persistent eosinophils

Mild infection that the body can handle well
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WBC- General Interpretation

• neutrophils ?
• mild left shift
• lymphocytes ?
• eosinopenia

Moderate or severe infection
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WBC- General Interpretation

• immature neutrophils ?
• segmented neutrophils ?

Grave condition
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WBC- General Interpretation

• neutrophils ?
• no immature neutrophils
• lymphocytes ?
• eosinophils ?

Stress (e.g., severe disease, pain) or steroid
influence
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WBC- General Interpretation

• monocytes ?

Chronic disease
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WBC- General Interpretation

• degenerative left shift
• falling lymphocyte numbers
• persistent lymphopenia
• persistent absence of eosinophils

Each of these signs Unfavourable prognosis
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WBC- General Interpretation

• falling WBC count together with increase in
  lymphocyte and eosinophil counts
• decreasing numbers of immature
  neutrophils

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Interpretation Medonic histogram (dog)
Platelets/Thrombocytes (PLT)
Platelets and Red blood cells / Erythrocytes (RBC)
White blood cells/Leukocytes (WBC) divided into
3 populations LYM, MID and GRAN
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Interpretation Medonic histogram (cat)
Platelets/Thrombocytes (PLT) typical for cat
low, flat curve with poor distinction from red
cells FD-flag
Platelets and Red blood cells/Erythrocytes (RBC)
White blood cells / Leukocytes (WBC) divided
into 3 populations LYM, MID and GRAN
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Interpretation Medonic histogram (horse)
Platelets/Thrombocytes (PLT) typical for horse
low, flat curve, relatively few platelets
Platelets and Red blood cells / Erythrocytes (RBC)
White blood cells / Leukocytes (WBC) divided
into 3 populations LYM, MID and GRAN
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Interpretation Numerical values
Platelet parameters Platelet count (PLT) Mean
platelet volume (MPV) Plateletcrit (PCT) Platelet
distribution width (PDW)
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Interpretation Numerical values
Red blood cell parameters Hemoglobin
(HGB) Hematocrit (HCT RBC x MCV) Red blood cell
count (RBC) Mean red cell volume (MCV) Mean cell
hemoglobin concentration (MCHC HGB/HCT) Red
cell distribution width (RDW)
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Interpretation Numerical values
White blood cell parameters White blood cells
count (WBC) Lymphocytes (LYM, LYM) Granulocytes
(GRAN, GRAN) Mid cells (MID, MID)
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Why review a blood smear?

• To identify among the white blood cells for
  example.
• Immature cells
• Toxic changes
• Monocytosis
• Eosinophilia
• Basophilia
• Mast cells
• Leukemia (blast cells)

• To identify among the red blood cells for
  example.
• Autoagglutination
• Eccentrocytes
• Echinocytes
• Spherocytes
• Heinz bodies
• Nucleated red blood cells
• Blood parasites in or on erythrocytes
• Parasites in plasma, e.g. microfilaria

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When should one review a blood smear?

• If you routinely make a blood smear it will
  always be available
• Blood samples that look very abnormal
• If WBC is lower or higher than normal, especially
  if over 30x109/L
• If the absolute count of lymphocytes (LYM) or mid
  cells (MID) is above normal
• If any parameter is outside normal range together
  with an instrument flag
• Blood samples with signs of anemia