Automation in hematology 2016

1. Dr.Titto rahim

2.  Process of replacement of tasks performed by
humans by computerized methods
 Semi-automated instruments
◦ Require some steps, as dilution of blood samples
◦ Often measure only a small number of variables
 Fully 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.

3.  Speed with efficient handling of a large
number of samples
 Accuracy and precision in quantitative blood
tests
 Ability to perform multiple tests on a single
platform
 Significant reduction of labor requirements
 Invaluable for accurate determination of red
cell indices

4.  Flags : flagging of laboratory test result
demands labor –intensive manual
examination of a blood smear
 Comments on red cell morphology cannot be
generated . Abnormal red cell shapes (such as
fragmented cells) cannot be recognized.
 Erroneously increased or decreased results
due to interfering factors
 Expensive with high running costs

5.  Electrical impedance
 Light scatter
 Fluorescence
 Light absorption
 Electrical conductivity

6. A stream of cells in suspension passes
through a small aperture across which
an electrical current is applied. Each
cell that passes alters the electrical
impedance and can thus be counted
and sized.

7.  Each cell flows in a single line through a flow
cell . A laser device is focused on the flow cell
as the laser light beam strikes a cell it is
scattered in various directions.One detector
captures the forward scatter light that is
proportional to cell size and other captures
the side scatter which is equal to cell
granularity & complexity

8.  Light absorption :Concentration of
hemoglobin is measured by absorption
spectrophotometry , after conversion of
hemoglobin to cynmethmoglobin
 Some analyzers use peroxidase cytochemistry
to classify leukocytes
 Electrical conductivity : Some analyzers use
conductivity of high frequency current to
determine physical and chemical composition
of leucocytes for their classification .

9.  Rbc count
 Hemoglobin
 Mean cell volume
 Mean cell hemoglobin
 Mean cell hemoglobin concentration
 WBC count
 WBC differential
 Platelet count
 Red cell distribution width
 Reticulocyte count

10.  Reticulocyte hemoglobin content
 Mean platelet volume
 Platelet distribution width
 Reticulated platelets

11. ◦ 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.

12.  The RBCs are counted automatically by two
methods
◦ Aperture impedance: where cells are counted as
they pass in a stream through an aperture.
◦ Or by light scattering technology
 The precision of an electronic counting for
RBCs is much better than the manual count,
and it is available in a fraction of time.
 This made the use of RBC indices of more
clinical relevance.

13.  Red cell count and volume are directly
measured by aperture impedance or light
scatter analysis . In a red cell histogram , cell
numbers are plotted on Y axis,white cell
volume on X-axis
 Analyzer counts those cells with volume of
36fl and 360 fl
 MCV is used for anemia classification in
microcytic, macrocytic and normocytic types

14.  Mean cell hemoglobin =hemoglobin (g/l)/red
cell count (10/ml)
 Mean cell hemoglobin concentartion (g/dl)=
hemoglobin(g/dl)/hemotocrit(%)
Hemocrit (%) =mean cell volume(fl)/red cell
count (10 /ml)

15.  RBC count
 Mean cell volume
 Red cell distribution width
 Hemoglobin
 Reticulocyte count
 WBC count
 Differential WBC count
 Platelet count
 Mean platelet volume

16.  Automated instruments produce volume
distribution histograms which allow the
presence of more than one population of cells
to be appreciated.most instrument produce a
quantitative measurement of variation in cell
volume, an equivalent of the microscopic
assessment of the degree of anisocytosis.
This is known as the RDW.

17.  The total WBC count is determined in whole
blood in which red cells have been lysed.
 Fully automated multichannel instruments
perform WBC counting by either
◦ Impedance
◦ Or light scattering
◦ Or both

18.  Automated differential counters which are
available now generally use flow cytometry
incorporated into a full blood counter rather
than being standard alone differential
counters
 Automated counters provide a three-part or
five- to seven-part differential count.

19.  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

20.  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).

21.  The accuracy of automated counters is less
impressive than their precision.
 In general automated differential counters are
favorable to the manual in 2 conditions
◦ Exam of normal blood samples
◦ Flagging of abnormal samples

22.  Platelets can be counted in whole blood using
the same tech. Of electrical or electro-optical
detection as are employed for RBCs.
 Other parameters include
◦ MPV
◦ PDW
◦ Plateletcrit= MPV x platelet count.

23.  An automated retic count can be performed
using the fact that various fluoro-chromes
combine with the RNA of the reticulocytes.
Fluorescent cells can then be enumerated
using a flowcytometer.
 An automated retic counter also permits the
assessment of retic maturity since the more
immature reticulocytes have more
RNAfluoresce more strongly than the mature
retics found normally in PB.

24.  They are precise but care should be taken so
that they are also accurate.
 Some problems which could be faced:
◦ 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