The total white blood cell count provides the number of leukocytes per cubic millimeter of blood. A range of 4,000 to 11,000 per cubic millimeter (mm3) of blood is considered to be normal.
1. The Unopette for white blood cell counts consists of three parts: reservoir\ pipette, and shield, The shield is used to introduce a hole into the reservoir. Puncture the reservoir with the shield before proceeding any further. The reservoir contains acetic acid which will destroy the red blood cells, leaving only white blood cells. The pipette, which has the number "25" etched in blue, is used to draw blood from the finger.
2. Scrub a finger with alcohol. Stick the finger with a sterile lancet. Immediately after using the lancet, place it in the bio-hazard container. Do not try to recap the lancet. Any disposable object contaminated with blood should be placed into the bio-hazard container.
3. Place the pipette into the blood at an angle slightly above horizontal. Capillary action will draw the blood into the pipette. The blood will only fill the pipette the correct amount. Do not be concerned about over-filling the pipette.
4. Immediately upon filling the pipette, place a finger over the wide end of the pipette, with your other hand squeeze the reservoir slightly, seat the pipette into the reservoir, remove your finger from the pipette, then let go of the reservoir. A slight vacuum is created in the reservoir and the blood will be sucked into the reservoir. Squeeze the reservoir several times to mix any blood in the reservoir with the acetic acid. The blood and acetic acid must stand for at least ten minutes or longer before it is ready to use. It can stand longer.
5. Charge the hemacytometer. To charge the hemacytometer, place the cover glass on the raised surfaces of the hemacytometer. Remove the pipette from the reservoir and insert the other end of the pipette into the reservoir. Squeeze out several drops of the mixture into a dry cotton ball. Place a small drop of the mixture on the polished counting surface of the hemacytometer next to the edge of the cover glass. Capillary action will suck the mixture under the cover glass. The chamber is properly filled when the polished counting surface is evenly filled with none of the mixture running into the moat around the counting surface.
6. Place the hemacytometer under the low power objective and locate the grid lines. Figure 26.1 shows the grid line arrangement of the hemacytometer. Note on the drawing the areas that have the large "W" marked on them. These four corner areas have each been subdivided into sixteen smaller grids. Count the white blood cells in each of the four large grids. On low power, the large grid area will almostfill the entire field of view. Using the mechanical hand counter, systematically count the sixteen smaller grids. To avoid over counting, count those cells that touch the grid lines on the left and top boundaries. Do not count those cells that touch the grid lines on the right and bottom boundaries.
7. To determine the number of white blood cells per cubic millimeter of blood, add the number of cells counted in the four large grid area and multiply the total by 50.
8. Once you have finished your count, place your Unopette for white blood counts into the bio-hazard container.
9: Record your total white blood cell count below.
Figure 26.1 Materials for WBC Count
Materials for RBC Count
Figure 26.1 Materials for WBC Count
Was this article helpful?
This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.