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Haematology
2 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
ParameterPARAMETER LASERCYTE QBC VETAUTOREAD IMPEDANZ SYSTEM
Hct Yes Yes Yes
Hgb Yes Yes Yes
RBC Yes Yes
Retics Yes Up to 4%
MCV Yes Yes
RDW Yes
MCHC Yes Yes Yes
MCH Yes Yes
WBC Yes Yes Yes
LYM Yes Yes ( Small )
MONO Yes Yes ( Middle )
NEU Yes Yes Yes ( Large )
EOS Yes Dogs and Cows
BASO Yes
PLT Yes Yes Yes
PCT Yes
PDW Yes
MPV Yes Yes
FIBRINOGEN Yes
NRBC’s Yes
3 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Eosinophils
Most frequent causes
Parasitic and allergic processes
Heartworm, Strongyle, Lung Flukes
Feline asthma, Flea bite dermatitis
Least frequent cause
Neoplasia, Fungal Infecion
Viral Infection ( FeLV )
Eosinopenia
When concurrent with lymphopenia is usually due to stress
Eosinophilia
4 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
What can cause changes in blood values?
Infections Bacteria Viral Funghi
Inflammation Intoxication Stress Anaemia Tumors Bleeding disorders Autoimmun diseases
5 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Why run Haematology inhouse?
• Blood samples consist of living cells and should therefore be analysed as quickly as possible, to avoid:
Changes in cells because of storage and transport
To minimise artefacts which can develop if the sample has contact to EDTA for a longer period of time
So treatment decisions are based on todays situation and not yesterdays
6 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Fresh Sample versus 48hr Sample
7 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
CBC Red cells (Erythrocytes)
White cells (Leucocytes) Granulocytes
- Neutrophiles - Eosinophiles
- Basophiles Agranulocytes
- Lymphocytes - Monocytes
Platelets (Trombocytes)
8 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
White differentials
• Typical “2 part” Diff Agranulocytes Granulocytes
• Typical “3 part” Diff Lymphocytes Monocytes Granulocytes
• Typical “5 part” Diff Lymphocytes Monocytes Neutrophile Grans Eosinophile Grans Basophile Grans
9 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
?What differentials do you get with..
QBC Autoread
LaserCyte
Impedance System
10 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Why can’t an impedance system give you a 5 part diff SIZE MATTERS !SIZE MATTERS !
11 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
LaserCyte….
Cells focused into a stream that passes through a laser light that interrogates them.
Light scatter is sensed by four photodiodes. Time of flight measurement also taken. Initial RBC count and platelet count taken. The RBC’s are then lysed using a mild agent. 5 part differential then performed qualiBeads are run with every sample. These act as an internal standard for quality assurance.
12 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
LaserCyte Technologie...
13 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
QBC Autoread…
The QBC uses centrifugation to separate cells by density.
The ‘float’ in the QBC tube reduces the volume of lumen in the area of the buffy coat.
This causes the cells to be spread out over a greater distance.
Cells take up the ‘acridine orange’ present in the tube (DNA and RNA/Lipoproteins).
Cell types are differentiated by the location and intensity of dye.
14 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
QBC VetAutoread
15 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Coulter® Principle
Impedance counters rely on the Coulter principle. When a particle passes through a narrow orifice, it causes a change in resistance. The magnitude of the change corresponds to cell size and the number of changes corresponds to cell size.
16 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Interfering Substances3 Part Impedance Technology
Giant / Clumped Platelets Results in erroneously low platelet counts. Erroneously high
WBC count. Can also be misclassified as RBC’s. nRBC’s and unlysed RBC’s
Unable to classify nRBC’s. nRBC’s result in erroneously high WBC count
Excessive eosinophils, metamyelocytes, blasts and plasma cells. Can cause erroneous monocyte count
Leukaemia and chemotherapy Harsh lysing agent can damage fragile cells
17 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Interfering Substances..
High WBC count WBC’s counted during RBC count. This can effect the red cell
parameters. (Hct, RDW,MCV and RBC) Agglutinated red cells
Can cause erroneously low RBC and can trap platelets. Microcytic cells and fragments
Can effect platelet count
18 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
Interfering Substances….
How does the operator know if you have abnormal cells present that may affect the results ?
How do they know if the results are due to the clinical condition or erroneous reading caused by abnormal cells?
Would you trust a system that could not flag ‘suspect’ results ?
19 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
ParameterPARAMETER LASERCYTE QBC VETAUTOREAD IMPEDANZ SYSTEM
Hct Yes Yes Yes
Hgb Yes Yes Yes
RBC Yes Yes
Retics Yes Up to 4%
MCV Yes Yes
RDW Yes
MCHC Yes Yes Yes
MCH Yes Yes
WBC Yes Yes Yes
LYM Yes Yes ( Small )
MONO Yes Yes ( Middle )
NEU Yes Yes Yes ( Large )
EOS Yes Dogs and Cows
BASO Yes
PLT Yes Yes Yes
PCT Yes
PDW Yes
MPV Yes Yes
FIBRINOGEN Yes
NRBC’s Yes
20 © 2004 IDEXX Laboratories, Inc., IDEXX Confidential
ABC Analyser – The Bad !
No retic information 3 Part Diff Impedance technology
Interfering substances 160 cycles include calibration / flushes / start up runs etc No data storage Few or no flags on abnormal samples Needs recalibrating every 6 months Different smart card per species
