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Purpose
To detect sickle cells in homozygous
sickle cell Anemia using Sodium Metabisulphite .This reduces oxygen tension in
Red Blood Cells.
Principle
Whole blood is diluted using
Sodium metabisulphite solution, which reduces Oxygen tension causing the Red
cells with sickle cells trait to assume a crescent shape.
Materials/
Reagents
Sodium meta-bisulphite solution,
slides ,cover slip ,Microscope , Pasteur pipette , Test tube
Standard
Procedure
·
Prepare a solution of 2% Sodium
Metabisulphite by dissolving 2.0g in 10ml of Distilled water
·
Add 0.5ml of whole blood to 0.5ml of 2% sodium metabisulphite in a test tube
·
Mix thoroughly and place a drop on a glass
slide, cover with a cover slide
·
Seal all the four edges with Vaseline
·
Leave at room temperature for one hour
·
Observe the red cell morphology under the
microscope
·
Proceed with the control in the same way
Results
and Interpretation
·
Normal Control will show normal red cells which retain their
biconcave discoid shape in the presence of
sodium metabisulphite
·
Sickle cell trait red cells will lose their characteristics
morphology due to reduced oxygen tension on the presence of sodium
metabisulphite (appearing crescent)
Normal cells vs Sickle cells
Quality
control: Use RBCs from known positive and Negative patients as control
Limitation:
Avoid
being confused with crenated ,Schistocytes or pencil RBCs
References
·
Monica cheesbrough, Medical Laboratory manual
for tropical countries ,Vol 12,2nd edition
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