Lab

Monocyte Count

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Monocyte Count, Monocyte, Macrophage

  • See Also
  1. Complete Blood Count
  • Characteristics
  1. Forms in Bone Marrow from Myeloblasts as with other Granulocytes (Basophils, Eosinophils, Neutrophils)
  2. Function: Phagocytizes dead or damaged cells
    1. Monocytes move 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
  • Interpretation
  • Normal
  1. Range: 2-8% of White Blood Cells
  • Causes
  • Increased
  1. Infection
    1. Viral Infection
    2. Parasitic Infection
  2. Inflammatory Bowel Disease
  3. Sarcoidosis
  4. Neoplasms
  5. Monocytic Leukemia
  6. Lymphoma
  7. Multiple Myeloma
  • Causes
  • Decreased
  1. Aplastic Anemia
  2. Lymphocytic Anemia
  3. Glucocorticoids
  • 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)
  • References
  1. Saiki in Friedman (1991) Medical Diagnosis, p. 227
  2. Abramson (2000) Am Fam Physician 62(9):2053-60 [PubMed]
  3. Riley (2015) Am Fam Physician 92(11):1004-11 [PubMed]