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RBC Manual Count. Erythrocyte Count. Principle: In order to facilitate RBCs count a specified volume of blood is diluted with a specified volume of isotonic fluid. Red cell diluting fluid must be : anti-coagulant anti-hemolysis. anti-aggregation. anti-Rouleaux. preserve RBC shape.
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Erythrocyte Count • Principle: • In order to facilitate RBCs count a specified volume of blood is diluted with a specified volume of isotonic fluid. • Red celldiluting fluid must be: • anti-coagulant anti-hemolysis. • anti-aggregation. • anti-Rouleaux. • preserve RBC shape.
Erythrocyte Count Diluting fluid: • One of the following solutions may be used: • Isotonic saline: • 0.85% sodium chloride (NaCl) in distilled water. • Hayam’s solution: • Sodium Sulphate10 g. • Sodium Chloride 2 g. • Mercuric Chloride 0.25 g. • Distilled Water 100ml • Gower’s solution: • Sodium Sulphate 12.5 g. • Glacial acetic acid 33.3 ml • Distilled water 100 ml. • Citrate-formalin solution: • Tri-sodium Citrate • Formalin
Note: In certain conditions, Hayam’s solution may cause clumping of RBCs and Rouleaux formations, while Gower's solution prevents these problems Sample: Whole blood using EDTA or heparin as anticoagulant. Capillary blood may also be used. Equipments: (Pipettes) used one of the following: Thoma pipette (RBCs) Micropipette –20l is the desired volume. Improved Neubauer chamber with the cover slips. Conventional light microscope. Clean gauze.
Procedure: 1. Dilution of the blood: • Thoma red count pipette. • Draw the blood up to exactly the 0.5 mark and dilute to the 101 mark. • Mix continuously for 2-3 minutes. • Load the cleaned hematocytometer. • Place the hematocytometer on the microscope stage, lower the condenser.
Procedure: • Focus with x10 objective lens on the large central square. This square is ruled into 25 small squares, each of which is further divided into 16 smaller squares, of the 25 squares, only the four corner squares, and one middle square are used to count RBCs. • Switch to 40 objective lens, and start counting in the five designated squares.
Calculations: • Total RBC Count = • N x Dilution Factor x Volume Correction Factor • Where: • N= the total number of red cells counted in the counting chamber. • Dilution 1: 200 • Dilution Factor = 200 • Counted Volume: • Volume correction factor = 50 • So, • Total RBC count = • N X 200 X 50 = N X 10.000