Monocyte Count


Monocyte Count, Monocyte, Macrophage

  • Characteristics
  1. Forms in Bone Marrow from Myeloblasts as with other Granulocytes (Basophils, Eosinophils, Neutrophils)
  2. Function: Phagocytosis of dead or damaged cells (similar to Neutrophils)
    1. Monocytes move from peripheral blood into tissue and become Macrophages
    2. Transformation to Macrophages controlled by Cytokines
    3. Macrophages directly perform the Phagocytosis
  3. Monocyte Morphology on Blood Smear
    1. Mononuclear Leukocyte (same class as Lymphocyte)
    2. Slightly larger than a Lymphocyte
    3. Kidney shaped nucleus
  4. Macrophages have specific names in certain tissues
    1. Osteoclast (Bone)
    2. Mesangial Cell (Kidney)
    3. Langerhans Cell (Skin)
    4. Alveolar Macrophage (lung)
    5. Microglia (Central Nervous System)
    6. Kuppfer Cell (Liver)
  • Labs
  • Normal
  1. Range: 2-8% of White Blood Cells
  • Causes
  • Increased
  • Causes
  • Decreased
  • Evaluation
  • Monocytosis (Monocytes >880/mm3)
  1. See Leukocytosis
  2. History and potential causes
    1. Travel and contagious contacts
  3. Diagnostics (consider)
    1. Chest XRay
    2. Specific infection testing (e.g. Monospot, PPD or quantiferon)
    3. Acute phase reactants (ESR, CRP)