Leukocyte (WBC) Disorders

Leukocyte (WBC) Disorders: Comprehensive Study Notes

I. Introduction to Leukocyte Characteristics & Basic Terminology

Cell Characteristics for Comparison

When evaluating white blood cells (WBCs), compare the following three characteristics:

1. Cell Size: Compare to a red blood cell (RBC).

2. Nucleus: Observe its shape.

3. Cytoplasm: Note its color and any inclusions present.

Suffixes to Remember

These suffixes indicate changes in cell numbers:

• ___________ philia = Increase in cell numbers

• _______cytosis = Increase in cell numbers

• __________ penia = Decrease in cell numbers

Key Definitions

• Leukocytosis: An increase (above the established reference range) in the total number of white blood cells (WBCs) in circulation, due to any cause. It represents the sum of all WBCs.

• Leukopenia: A reduction in the total number of white blood cells (WBCs) in circulation.

• Left Shift: The appearance of increased numbers of immature WBCs in blood circulation. A classic example is the presence of Band neutrophils in the blood. In most species, the presence of immature neutrophils (like Band cells) is the primary determinant of a Left Shift.

II. Neutrophil Population and Left Shift

Understanding the Left Shift

A Left Shift, indicating the release of immature neutrophils from the bone marrow, can be classified as either Regenerative or Degenerative.

• Regenerative Left Shift:

  • Characterized by an increased total white cell count and an increased number of immature WBCs in circulation.

  • Crucially, mature cells still outnumber immature cells.

  • Represents an early, appropriate response to increased demand for neutrophils.

• Degenerative Left Shift:

  • Characterized by a normal or even low total white cell count, but with immature cells out-numbering mature cells.