Red Blood Cell Count (RBC count) (MANUAL METHOD, Purpose, Procedure, and Normal values.

Red Blood Cell Count(RBC count) (MANUAL METHOD) : Purpose, Procedure, and Normal values.

RED CELL COUNT (MANUAL METHOD)

RED CELL COUNT (MANUAL METHOD)

RED CELL COUNT (MANUAL METHOD)

Principle of RBC Count:-  

Whole blood is diluted appropriately using an isotonic diluent to avoid lysis of red cells. The number of red cells in a known volume and of known dilution is counted using a counting chamber.

RBC Diluting fluid:- 

(Formal citrate) Sodium citrate3.0 g

Formaldehyde1.0 ml Distilled water,99.0 ml Alternatively, 0.85 % sodium chloride may be used.

Specimen:- 

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

Procedure of RBC Count:-

Prepare 1:200 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 3.98 ml of diluting fluid.

• Charge the improved Neubauer counting chamber carefully with the well mixed diluted blood. 

• If 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 to 5 minutes.

• Locate the ruled area of the counting chamber under 10x objective of the microscope. Check that the cells are evenly distributed.

Using 40 x objective, count the total number of red cells in five groups of 16 small squares in the central ruled area (areas A, B, C, D and E in Fig. 3.5), which is equal to 80/400 mmi.e.0.2 mm2

method of cunting cells in a ruled area

Calculation:-

  Total red cell count/cu.mm

 

Normal velues 

• Normal RBC range for men is 4.7 to 6.1 million cells per microliter (mcL).

• The Normal RBC range for women who aren't pregnant is 4.2 to 5.4 million mcL.

• The Normal RBC range for children is 4.0 to 5.5 million mcL.

Clinical significance of blood cells count

Clinical significance of blood cells count

Note

If the patient is very anaemic or if less than 400 cells have been counted, the dilution of blood should be decreased to 1/100 by filling the pipettes with blood to the 1.0 mark instead of the 0.5 mark.