PCV and RBCs count PDF

Hematocrit Value (Hct) Packed cell value(PCV) Definition of Hematocrit: It is the percentage ratio of the RBCs volume to the total blood volume. Also, known as the packed cell volume, or PCV. NB: (hematocrit from the Greek = blood separation) For example: a hematocrit value of 40% means t...

Hematocrit Value (Hct) Packed cell value(PCV) Definition of Hematocrit: It is the percentage ratio of the RBCs volume to the total blood volume. Also, known as the packed cell volume, or PCV. NB: (hematocrit from the Greek = blood separation) For example: a hematocrit value of 40% means that there are 40 milliliters of RBCs in 100 milliliters of blood. identify the equipment in the lab: 1. Sterile the finger then pricks it with a Lancet 2. Allow blood to enter a special heparinized capillary tube till 2/3 its length.. 3. Clean the capillary with a wipe and seal it with clay 4-Put the tube in the centrifuge with sealed end out. 5-Balance the centrifuge 6-Put the cover and centrifuge for 5-10 minutes to separate the blood cells form plasma. Measure The percentage volume of RBCs is determined by using special graduated scale(hematocrit chart).  Measure The percentage volume of RBCs is determined by using special graduated scale(hematocrit chart).  How to Calculate the PCV: PCV = (RBCs Volume x 100 )/ Total blood volume Normal average In healthy adult individuals: Gender Average Male 46% Female 42% Clinical Significance for measuring PCV Increase PCV Decrease PCV Polycythemia Anemia RBC’s Count To determine total number of red blood cells present in one µl of blood sample. Principle: The blood sample is diluted (usually 200 times) with isotonic solution then the red blood cells will be counted under magnification.  HEMOCYTOMETER Hemo: blood Cyto: cell Meter: measurement/counter  WBCs counting area (16 big squares) One big square Each one is divided into 16 small squares The dimension of each small squares length= 1/20 mm Width= 1/20 mm RBCs counting area Depth= 1/10 mm (25 big squares)  Procedure: 1. Prick the clean finger with lancet and withdraw the blood in the RBC pipette up to 0.5 mark. 2. Then withdraw isotonic solution up to 101 mark. 3. Rotate the pipette equally in your hands to mix the solution well by swirling. 4. Allow a small drop of diluted blood to spread into the counting chamber. 5- Leave the hemocytometer for 3 min. to allow the cells to settle. 6- Focus with x10 objective lens on the large central square. This square is divided into 25 small squares, each of which is further divided into 16 smaller squares. 7- Only the four corner squares, and one middle square are used to count RBCs. 8- Switch to 40 objective lens and start counting in the five designated squares. 10X magnification showing RBCs counting area (25 big squares) 40X magnification showing 16 small squares of each big square  Calculations: Total RBC Count = No. of counted cells Volume of small square X dilution X no. of small square No. of counted cells 1/4000 X 1/200 X 80 Normal values 5.5 million cells/μl in males 5 million cells/μl in females Clinical Significance RBCs count is increased in polycythemia RBCs count is decreased in anemia Polycythemia: A clinical condition in which the red blood cell count is above normal due to increased activity of bone marrow and excess production of red blood cells. There is an increase in hemoglobin content and increase in packed cell volume (PCV) a. Pathological polycythemia: as in Hypoxia due to heart or lung disease. b. Physiological polycythemia: Due to hypoxia as in case of living in high altitude Thanks