1.2.5 Anatomy, Physiology, and Health Education I Laboratory
Lab 6 Total Leukocyte count with improved Neubauer's chamber (Cont'd...)
Causes of Leucopenia: i. certain viral (hepatitis, influenza, measles, etc.),
and bacterial (typhoid, paratyphoid, tuberculosis, etc) infections ii. primary bone marrow depression (aplastic anaemia)
iii. secondary bone marrow depression (due to drugs, radiation, etc.) iv. anaemia (iron deficiency megaloblastic etc).
Clinical significances of differential leukocyte count:
Requirements: Microscope, Improved Neubauer's Chamber, WBC pipette, WBC diluting fluid
[It is prepared as follows: a) Glacial acetic acid: 2.0 ml, b) 1 % (w/v) gentian violet: 1.0 ml, c) Distilled water: 97 ml.
This solution is stable at room temperature (25°C ± 5°C). A pinch of thymol may be added as preservative], Double oxalated or EDTA blood.
Procedure: Make a 1:20 dilution of blood. Cork the tube tightly and mix the suspension by rotating in a cell-suspension mixer for
at least 1 minute. Fill the Neubauer counting chamber by means of a Pasteur pipette or glass capillary (the depth of the
fluid should be 0.1 mm). Focus on one of the 'W' marked areas (each having 16 small squares) by turning objective to low
power (10 X). Count cells in all four W marked corners.
Number of white cells/cu mm (µl) of whole blood = (number of white cells counted * dilution/ 16) / (depth of fluid * 1/4x
1/4). [Dilution = 20; Depth of fluid = 0.1 mm (constant)]
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