BASIC HAEMATOLOGY
BLOOD CONSTITUENTS
RBC’S WBC’S PLT’S PLASMA
BONE MARROW
STEM CELLS
Late normoblasts WBC’S Megakaryocytes
Granulocytes Non-granulocytes
Reticulocytes Neutrophils Lymphocytes PLT’S
Eosinophils Monocytes
RBC’S Basophils
Notes
RBC’s – Live ~ 120 days Spleen; Hb broken down in Liver to Bile Acids & Bilirubin. NB. Decrease in size as they get older.
Lymphocytes
B-Lymphocytes (Bone Marrow) – Produce Ab’s against invading antigens eg. Viruses.
T-Lymphocytes (Thymus) – Ab’s are bound to the cell membrane (“Killer” T cells).
Monocytes
Phagocytic - “eat foreign bodies, antigens, debris, etc.
Neutrophils & Eosinophils
Contain proteolytic enzymes to break down cell walls.
Basophils contain Histamine & Heparin (Inflammatory processes) and are also thought to be involved in the metabolism of Fat.
Erythropoietin – produced by Kidneys in response to low O2 levels in blood gives increase in RBC’s.
RED BLOOD CELLS – ERYTHROCYTES
ANAEMIA
Decrease in Hb, HCT, & RBC’s
· Blood Loss (Internal/External Bleeding)
· Haemolysis (destruction)
· Bone Marrow Disease
· Iron Deficiency (Haemoglobin)
Bone Marrow Disease
· Non-regenerative Anaemia – No Retics despite Anaemia
· Regenerative Anaemia – Bone Marrow Retics
RDW RDW
RBC
No’s
RBC Size Retics Present
(Larger RDW)
Retics present Increased MCV
Decreased MCHC
Iron Deficiency
Lack of Hb Smaller RBC’S with less Hb
(MCV Decreased) (MCHC Decreased)
NB. Decreased MCV also results from Porto-systemic shunts due to Iron assimilation in the Liver.
POLYCYTHAEMIA
Increase in RBC’s
· Dehydration
· Bone Marrow disease
· Rarely – Cardiovascular Disease; Kidney malfunction; Polycythaemia vera
PLATELETS – THROMBOCYTES
Megakaryocytes Platelets Blood Clots
Thrombocytopenia (increase) – If MPV unchanged evaluate bone marrow.
Thrombocytosis (decrease) – Blood loss; Iron deficiency;
Bone Marrow Cancer.
WHITE CELLS – LEUCOCYTES
LYMPHOCYTES
Produce Ab’s against non-bacterial diseases ie. Viruses
Lymphocytosis (Increase)
· Viral diseases
· Stress (Cats & Horses) due to Adrenaline.
· Leukemia
Lymphopenia (decrease)
· Steroid therapy
· Steroid release from Adrenals (Cushings)
· Distemper or Parvo
MONOCYTES
2nd line of defence against Micro-organisms/Bacteria (after Neutrophils)
Monocytosis – Chronic disease; Stress; Steroid diseases
Monocytopenia – Irrelevant in Vet. Medicine
NEUTROPHILS
1st line of defence against Micro-organisms/Bacteria or inflammatory diseases.
Neutrophilia – Band Neutrophils (immature forms) released form Bone Marrow in response to inflammation. (Left – shift).
- Chronic stress – due to steroid release (eg. Cushings) but no bands.
Neutropenia – Invader is winning
EOSINOPHILS
Eosinophilia – Hypersensitivity (Allergic Reactions)
- Parasites (Fleas, Ticks, worms in horses)
Eosinopenia – Steroid mediated stress.
BASOPHILS
Normal to have none.
Basophilia – Very rare in Vet. Medicine
- Hypersensitivity (as above)
- Very rare cancers in dogs.
Basopenia – Does not exist.
HAEMATOLOGY ANALYSERS
12ul sample
~6 x 106 /mm RBC’s ~10 x 103 /mm WBC’s
PLT’s Hb
(+WBC’s very small nos) (RBC’s lysed Hb)
1/20,000 Dilution 1/300 Dilution
REQUIRE A FLOW OF SINGLE CELLS
Two commonly used methods:
Laminar flow Cytology Small aperture aspiration
(Hydrodynamic Focusing)
Partial
0 0 0 0 0 o vacuum
24 hour maintenance.
· CDC – WBC’s & RBC’s ABC – WBC’s & RBC’s
· Sysmex – WBC’s HMT – WBC’s & RBC’s (MS5)
· Celldyne – WBC’s & RBC’s Sysmex – RBC’s
Celldyne – WBC’s & RBC’s
Cellyvet – Vetlab
Medonic – Menarini
COUNTING METHODS
a) Impedance
To achieve diff use “lyse” reagent that shrinks white cells.
Eg. ABC: Lympho’s>Mono’s>Neutro’s>Eosino’s
b) Laser Scatter (eg. Sysmex, Celldyne, Lazercyte)
Sensor Source
Side Scatter
Front
Scatter Monocytes
Sensor
Lymphocytes
Front Scatter
Side Scatter
OTHER TYPES OF HAEMATOLOGY ANALYSERS
a) VS2000 – Hematek
OHP’s
b) QBC – Quantitative Buffy – Coat
Haematocrit tubes coated with fluorescent dye which results in differential staining of DNA & RNA in the White cells, Reticulocytes & Platelets.
Uses small plastic “float” to separate white cells in Buffy Coat.
Buffy Coat
P B E N M L R
PLASMA RBC’s
Detector UV Source
NB. Floating discriminators in Impedance/ Laser Scatter Counters simply refer to the ability to change cut-off points between different types of cells in different species.
Viz a viz Smart Cards in the ABC.