Hematology I Laboratory Manual - Experiment 7 - The Hemocytometer PDF

HEMATOLOGY I LABORATORY MANUAL Name: Date: Section: Group: Score: EXPERIMENT 7 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 counti...

HEMATOLOGY I LABORATORY MANUAL Name: Date: Section: Group: Score: EXPERIMENT 7 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: 1. Describe the basic parts and functions of a hemacytometer 2. Count blood cells using the hemacytometer 3. Identify the pitfalls in lling the counting chamber MATERIALS: Microscope Hematocytometer: Improved Neubauer counting chamber Red blood cell pipette White blood cell pipette Charts of counting chambers: Improved Neubauer Neubauer Fuchs-Rosenthal Speirs-Levy DIFFERENT TYPES OF COUNTING CHAMBER • • • • • • • Improved Neubauer Neubauer Fuchs-Rosenthal Speirs-Levy Buerker's and Tuerk's Bass-Jones Thoma Improved Neubauer Counting Chamber fi 1 HEMATOLOGY I LABORATORY MANUAL The improved Neubauer counting chamber is made of heavy colorless glass. On the middle third of the chamber, there are three parallel platforms extending across the slide and separated by moats. The central platform is subdivided by a transverse groove into halves, each wider than the two platforms (Fig. 7.1). The central platform is exactly 0.1 mm lower than the lateral platforms. Each of the halves of the central platform has the improved Neubauer ruling which consists of a primary square measuring 3 x3 mm (9 mm2) and is subdivided into nine secondary squares each measuring 1x1 mm (Fig. 7.2) The four-corner secondary squares (designated as W1, W2, W3, and W4) are used for WBC count and are subdivided into 16 tertiary squares. The central secondary square is divided into 25 tertiary squares, each measuring 0.2 mm. Furthermore, each of these tertiary squares is subdivided into 16 smaller squares. The total number of smaller squares in the central secondary square is 400. As a rule, RBs are counted on ve of the tertiary squares (designated as R1, R2, R3, R4, and R5) totaling to 80 smaller squares. A thick coverslip ground to perfection is necessary when using the counting chamber. An ordinary coverslip cannot be used because of its uneven surface. When the thick placed on top of the platform of the counting chamber, there is a space exactly 0.1 mm between the coverslip and the ruled platform. Neubauer Counting Chamber The Neubauer counting chamber is similar to the Improved Neubauer counting chamber except that the central secondary platform is divided into 16 tertiary squares only (Fig. 7.3). fi 2 HEMATOLOGY I LABORATORY MANUAL Fuchs-Rosenthal Counting Chamber The Fuchs-Rosenthal counting chamber is considerably larger than the Neubauer counting chamber. Its principal use is in the performance of low cell count, such as eosinophil count, spinal uid count, and leukopenic blood count. The ruled area measures 4x4 mm, and the depth is 0.2 mm. The central ruling is divided into 16 smaller squares (Fig. 7.4). Speirs-Levy Counting Chamber The Speirs-Levy counting chamber consists of four sections, two on each side of the counting chamber. Each ruled area consists of 10 squares each measuring 1 x 1 with a total area of 10 mm2. The squares are arranged in two horizontal rows of ve squares, which are further subdivided into 16 squares. The chamber has a depth of 0.2 mm (Fig. 7.5). fl fi 3 HEMATOLOGY I LABORATORY MANUAL The Red Blood Cell Pipette RBC pipette may be easily distinguished from the WBC pipette because it has either a red bead inside the mixing chamber or a red stripe on the stem. The stem is the portion from 0.0 to 1.0 containing one unit of volume. The mixing chamber or bulb is the area from 0.1 to 101 and holds 100 units of volume. Its bore is smaller than that of a WBC pipette. The White Blood Cell Pipette The stem of the WBC pipette is the portion from 0.0 to 1.0 and the mixing chamber is the portion from 1.0 to 11. The volume of the stem is exactly 10 times the volume of the mixing chamber. Thus, the bulb holds 10 units of volume. 4 HEMATOLOGY I LABORATORY MANUAL Name: Section: Date: Group: Score: REVIEW QUESTIONS 1. In a tabulated form, summarize the differences between RBC and WBC pipettes. Points of differentiation RBC pipette WBC pipette 2. Give other tests employing the two pipettes aside from RBC and WBC counts. 3. Describe the proper way of cleaning the Thoma diluting pipettes. 5