محمد الشويلي المـديـر العـــام
جنسيـﮯ : مساهماتيـﮯ : 2740 عمريـﮯ : 45 نقاطيـﮯ : 3460
| موضوع: RBC Count الثلاثاء يوليو 07, 2015 12:32 am | |
| بسم الله الرحمن الرحيم RBC Manual Count
Introduction • Red blood cells make up almost 45 percent of the blood volume. • Their primary function is to carry oxygen from the lungs to every cell in the body. • Red blood cells are composed predominantly of a protein and iron compound, called hemoglobin, that captures oxygen molecules as the blood moves through the lungs, giving blood its red color. • As blood passes through body tissues, hemoglobin then releases the oxygen to cells throughout the body.
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 Diluting fluid: • One of the following solutions may be used: 1. Isotonic saline: – 0.85% sodium chloride (NaCl) in distilled water. 2. Hayam’s solution. 3. Gower’s solution. 4. Citrate-formalin solution. Sample: – Whole blood using EDTA or heparin as anticoagulant. Capillary blood may also be used. Equipment's: – (Pipettes) used one of the following: • Thoma pipette (RBCs) • Micropipette –20ml . – Improved Neubauer chamber with the cover slips. – Microscope. – Clean gauze. – Procedure: 1. Dilution of the blood: – Micropipette (20m) 1:201 dilution. • Pipette 4.0ml of diluting fluid into a tube • Pipette 20ml of will mixed anticoagulated whole blood to the tube. – 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. 2. Load the cleaned hematocytometer. 3. Place the hematocytometer on the microscope stage, lower the condenser 4.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. 5.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 – N = the total number of red cells counted in the counting chamber. – Dilution 1: 200 Dilution Factor = 200 Counted Volume: – Each counted square has a volume of 0.2 X 0.2 X 0.1 = 0.004 – 5 squares volume = 5 X 0.004 = 0.02 mm – Volume correction factor = 1/0.02 = 50 Total RBC count = – N X 200 X 50 = N X 10.000 Discussion 1. In certain conditions, such as polycythemia, the red blood cell count may be extremely high, which makes it difficult to obtain an accurate count. In this instance, make a larger dilution of blood. For a 1:301 dilution, add 20mL of whole blood to 6.0mL of diluting fluid. 2. For a patient who has severe anemia and in whom the RBC is low, make a 1:101 dilution by adding 20mL of whole blood to 2.0mL of diluting fluid. 3. Make certain the pipettes, hemacytometer, and cover glass are free from dirt, lint, and dried blood. Ensure that the diluting fluid is free from blood and other contamination. 4. RBC takes longer to perform than a WBC because of the larger number of cells. Therefore, proceed as quickly as possible once the cells have settled. Drying of the dilution in the counting chamber causes inaccuracies in the final cell count. 5. The range of error for a manual RBC is generally about 10 to 20%.
الموضوع الاصلي : RBC Count المصدر : مستشفى الرفاعي العام | |
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