Cell counting techniques

Examining CSF with the Hemacytometer (continued)

  • White cells are less refractile and appear somewhat granular in appearance. In general, white cells will be larger than red cells. The segmented nucleus in neutrophils can be seen on high power. Lymphocytes and monocytes may be more difficult to differentiate in an undiluted, unstained specimen.
  • If cells are counted in the four corner squares and the center square on both sides of the hemacytometer, the number of cells counted equals the number of cells/mm3 which is the equivalent of cells/µL.
  • The ruled area of one side of a hemacytometer is shown on the right, marked with routine counting squares for red and white cell counts. Each large square is 1 mm2 by 0.1 mm in depth. If the four corner squares that are marked "W" in the image and the entire center square are counted on both sides of the hemacytometer, the area is equal to 10 square millimeters (10 mm2) and the total volume is 1 mm3 (10 mm2 x .1 mm = 1 mm3).

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