Figure 7-13.Loading the counting chamber.

Figure 7-11.Preparing reservoir to receive blood from the capillary tube

Hospital Corpsman Revised Edition - Complete Navy Nursing manual for hospital training purposes
Page Navigation
264

7. Immediately prior to cell counting, mix again by gentle inversion, taking care to cover the upper opening of the overflow chamber with your index finger. 8. Place the coverglass on the hemacytometer counting chamber, making sure coverglass is clean and free of grease. (Fingerprints must be completely removed.) 9. Remove the pipette from the reservoir. Squeeze the reservoir and reseat the pipette in the reverse position, releasing pressure to draw any fluid in the capillary tube into the reservoir. Invert and fill the capillary pipette by gentle pressure on the reservoir. After discarding the first 3 drops, load (charge) the counting chamber of the hemacytometer by gently squeezing the reservoir while touching the tip of the pipette against the edge of the coverglass and the surface of the counting chamber (fig. 7-13). A properly loaded counting chamber should have a thin, even film of fluid under the coverglass (fig. 7-14, view A). Allow 3 minutes for cells to settle. If fluid flows into the grooves (moats) at the edges of the chamber or if air bubbles are seen in the field, the chamber is flooded and must be cleaned with distilled water, dried with lens tissue, and reloaded (fig. 7-14, view B). If the chamber is underloaded, carefully add additional fluid until properly loaded. 10. Place the loaded hemacytometer into a petri dish with a piece of dampened tissue to keep the hemacytometer from drying out (fig. 7-15). Allow 5 to 10 minutes for the cells to settle. 11. Once the cells have settled, place the hemocytometer on the microscope. Use the low-power lens to locate the five small fields (1, 2, 3, 4, and 5) in the large center square bounded by the double or triple lines. See figure 7-16. Each field measures 1/25 mm², 1/10 mm in depth, and is divided into 16 smaller squares. These smaller squares form a grid that makes accurate counting possible. 12. Switch to the high-power lens and count the number of cells in field 1. Move the hemacytometer until field 2 is in focus and repeat the counting procedure. Continue until the cells in all five fields have been counted. Note the fields are numbered clockwise around the chamber, with field 5 being in the center. 7-13 HM3f0712 Figure 7-12.—Mixing blood sample and diluent. HM3f0713 Figure 7-13.—Loading the counting chamber.

Privacy Statement
Press Release
Contact