The Hemacytometer PDF

The Hemacytometer The hemacytometer is used to count the cellular elements of the blood, namely the red blood cells (RBCs), the white blood cells (WBCs), and the platelets. It consists of the following: the counting chamber, the WBC pipette, and the RBC pipette. Accessory devices such as the...

The Hemacytometer The hemacytometer is used to count the cellular elements of the blood, namely the red blood cells (RBCs), the white blood cells (WBCs), and the platelets. It consists of the following: the counting chamber, the WBC pipette, and the RBC pipette. Accessory devices such as the suction device and thick coverslip are also required for manual counting of cells. OBJECTIVES: Describe the basic parts and functions of a hemacytometer Count blood cells using the hemacytometer Identify the pitfalls in filling the counting chamber. Hemacytometer Hemo: blood Cyto: cell Meter: measurement Thus, it is an instrument used to count the blood cells. Materials: Microscope Charts of counting Hemacytometer: chambers: Improved Neubauer Improved Neubauer counting chamber Neubauer Red blood cell pipette Fuchs- Rosenthal White blood cell pipette Speirs-Levy Hemocytometer? A hemocytometer is a square chamber carved into a piece of thick glass that has a specific depth. It is used to calculate the density of cells in suspensions. It’s called hemocytometer (or hemacytometer / haemocytometer, but not hematocytometer). Hemo, for blood; cyto, for cell; meter, for measuring. So altogether: measuring blood cells. Different types of Counting Chamber Ordinary Neubauer counting chamber Improved Neubauer counting chamber Levey’s counting chamber Fuch’s Rosenthal chamber NEUBAUER’S SLIDE Thick glass slide with two ruling area on centre Ruled area are separated by H-shaped gutter/trough Beyond the two vertical arm of trough there are two raised shoulder (ridge) which support cover glass. Lining is coated by shining metal or rhodium  Each scale is 3mm wide and 3 mm long. Depth of the chamber is 0.1 mm. The whole scale is divided into 9 big squares. Each square is 1 mm long and 1 mm wide.  The four corner squares are further divided into sixteen smaller squares and are used for WBC counting. Four corner squares are meant for WBC counting. Total 64 small squares.  Central square is divided into 25 medium sized square and are separated by triple line. The medium sized square are further divided into 16 small square (tiny) The four corner and central square are used for platelets and RBC count. Counting Rule Do not count cells touching Bottom line Right line > This is to avoid double counting. Counting rule Thomas pipette Consist of graduated capillary tube, mixing bulb with glass bead and aspirating tube. Parts: stem, bulb , rubber tube Thomas pipette are: WBC and RBC pipette. How does a hemocytometer work? This big square has other little squares inside, following the pattern below: Differences between RBC and WBC pipette RBC WBC It has a red bead It has a white bead It has graduations up to It has graduations up to mark 101. mark 11. Size of bulb is larger Size of bulb is smaller Size of lumen is smaller Size of lumen is larger Cover slip Special cover glass with smooth surface and even thickness. Thickness = 0.3, 0.4, 0.5 mm Length = 16 x 22 mm, 22 x 23 mm Sources of error False high count: False low count: Improper mixing Blood diluted with tissue fluid Uneven distribution of cells Undue delay in counting of cell. Error in pipetting Clumping of cells. Error in calculation Uneven distribution of cells Blood taken from area of Faulty technique of hemo concentration. counting Yeast , dirt and leukocyte Improper standardized are counted as RBC. counting chamber. Thank you…….. Rey A. Lovendino, RMT, MSPH