LAP4

LAB4
Blood cell count
Counting of blood cells are done either by an electronic cell counter or manually with the special glass slide known (Hemocytometer). Since many different formed elements are in the blood in high concentration, blood must be diluted before counting. The diluting fluid is selected for its ability to :-
Dilute the blood , lyses cell types not wanted , stain cell types want to count .
Blood cell counts are usually reported in number of cell per cubic millimeter (no. of cells / mm) or per microliter (no. of cells / ul.) (1 ul. = 1 mm).
Red Blood Corpuscles Count :-
Normal erythrocytes may be described as biconcave discs ; they are thicker at the edges than in the middle why ? During development R.B.Cs loss their nuclei and most of their organelles thus they are unable to divide . Each erythrocyte contains large quantities of Hb that allow O2 & CO2 to be carried in R.B.Cs.
The biconcave shape increases the surface of area thus greatly facilitating to exchange the blood gas.
The lack of nucleus gives the R.B.C great flexibility & elasticity and folded when move through very narrow blood capillaries . Also the round edges reduce the friction the cells in the capillaries.
Erythrocytes live for about 122 days in males and 112 days in females.
Principle:-
Whole blood is diluted with an isotonic diluent, the number of cells in affixed volume is counted and the final count is expressed as the number of cells in one cubic millimeter (No. of cells / 1 mm) of undiluted blood
Reagent & Equipments:-