HEMA 2 LEC - Automation in haematology Flashcards
Require some steps, as dilution of blood samples
Often measure only a small number of variables
Semi-automated instruments
Require only that an appropriate blood sample is presented to the instrument.
They can measure 8-20 variables including some new parameters which do not have any equivalent in manual methods.
Fully automated instruments
Sizing is based on
impedance technology.
Hb is measured automatically by a modification of the
manual (cyanide) method.
To reduce toxicity of Cyanide some systems replace it by a non-toxic material ?
Na- lauryl sulphate
The RBCs are counted automatically by two methods
2
Aperture impedance
light scattering technology
cells are counted as they pass in a stream through an aperture
What method of counting rbc
Aperture impedance:
Some problems which could be faced:
3
Two cells passing through the orifice at the same time, counted as one cell. RBC agglutination(clump of cells) Counting bubbles or other particles as cells.
allows either the PCV or the MCV to be determined.
Pulse height analysis
Fully automated multichannel instruments perform WBC counting by either
(3)
Impedance
Or light scattering
Or both.
Automated differential counters which are available now generally use _____ incorporated into a full blood counter rather than being standard alone differential counters
flow cytometry
3-part differential usually cont
Granulocytes or large cells
Lymphocytes or small cells
Monocytes(mononuclear cells) or (middle cells)
5-part classify cells to
Neutrophils Eosinophils Basophils Lymphocytes Monocytes
A sixth category designated “large unstained cells” include cells larger than normal and lack the peroxidase activity this include
Atypical lymphocytes
Various other abnormal cells.
Other counters identifies 7 categories including
Large immature cells(composed of blasts and immature granulocytes) Atypical lymphocytes(including blast cells).
Analysis in diff count may be dependant on:
Volume of the cell
Other physical characteristics of the cells
Sometimes the activity of cellular enzymes such as peroxidase.
technologies used in diff count
Light scattering and absorbance
Impedance measurement
In general automated differential counters are favourable to the manual in 2 conditions
Exam of normal blood samples
Flagging of abnormal samples
An automated retic count can be performed using the fact that ____ Fluorescent cells can then be enumerated using a flowcytometer.
various fluoro-chromes combine with the RNA of the reticulocytes.
An automated retic counter also permits the assessment of since
retic maturity
the more immature reticulocytes have more RNA fluoresce more or less ?? strongly than the mature retics found normally in PB.
moe strongly
Automated instruments produce ______ which allow the presence of more than one population of cells to be appreciated
volume distribution histograms
Automated instruments produce volume distribution histograms which allow what?
the presence of more than one population of cells to be appreciated
variation in cell volume,
RDW
an equivalent of the microscopic assessment of the degree of anisocytosis
RDW
RDW is an equivalent of the microscopic assessment of the degree of ___
anisocytosis
The total WBC count is determined in whole blood in which __ have been lysed.
red cells
Automated differential counters which are available now generally use flow cytometry incorporated into a ____ rather than being standard alone differential counters
full blood counter
Monocytes other name (2)
mononuclear cells
middle cells
large cells
granulocytes
small cells
lymphocytes
6th category in diff count automated is called
“large unstained cells”
include cells larger than normal and lack the peroxidase activity
“large unstained cells”
Automated differential counters employing_____ classify far more cells than is possible with a manual differential count.
flow cytometry
Other parameters in PLT automated count include (3)
MPV
PDW
Plateletcrit= MPV x platelet count
formula for plateletcrit
MPV x PLT count
sysmex model
Sysmex XE-2100
