WHITE CELL COUNT (TOTAL, TLC) (MANUAL METHOD

WHITE CELL COUNT (TOTAL, TLC) (MANUAL METHOD)

WHITE CELL COUNT (TOTAL, TLC) (MANUAL METHOD)

Principle:- Whole blood is diluted appropriately using a diluent which haemolyses red cells, leaving all the nucleated cells intact. The number of white cells in a known volume and known dilution are counted using a counting chamber. 

Diluting fluid:- Acetic acid, 2% (v/v), tinged with gentian violet.

Specimen:- Whole blood, anticoagulated with EDTA. Capillary blood can be used if it is diluted immediately after collection.

Technique:- Prepare 1:20 dilution of the blood in the diluting fluid in a Thoma pipette or using Unopette system, as described earlier.Alternatively, add 0.02 ml of blood to 0.38 ml of diluting fluid.

Charge the improved Neubauer counting chamber with the well-mixed diluted blood. Thoma pipette is used, remember to discard first 3-5 drops before charging the chamber.

Allow the cells to settle in a moist chamber for 3-5 minutes.

Using 10 x objective of the microscope, locate the four large corner squares (areas 1, 2, 3 and 4 . The area of these squares is 4 mm. Check that the cells are evenly distributed.

Count the total number of white cells in the four large corner squares in the same pattern as described for the red cell count

calculation :- toatal white cells count./cu.mm(or µl)

Normal range:- Adult: 4.500-11.000cu.mm (4.5 to 11.0× 10⁹/L)

Neonates: 10.000 – 25.000/cu.mm(10.0-25.0 ×10⁹/L)