differential blood count

differential blood count

The number and type of white blood cells as determined by microscopic examination of a thin layer of blood on a glass slide stained to show the shape of the various cells. The number and variety of white cells in a sample of a given size are obtained. Even though the red cells are not counted by this method, their shape, size, and color can be evaluated. Some blood diseases and inflammatory conditions may be recognized in this way. In a differential count, the varieties of the leukocytes and their percentages normally should be: neutrophils (segmented), 40% to 60%; eosinophils, 1% to 3%; basophils, 0.5% to 1%; lymphocytes, 20% to 40%; monocytes, 4% to 8%.

See also: count

differential blood count

An assessment of the percentage numbers of the various types of white cells present in the blood-the neutrophil polymorphs (40–75%), lymphocytes (20–45%), monocytes (2–10%), eosinophils (up to 6%) and basophils (up to 1%). Changes in the normal percentages are usually significant.