Lab

Complete Blood Count

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Complete Blood Count, CBC

  • Efficacy
  1. Complete Blood Count is over-utilized in acute infectious illness
    1. Does not distinguish Sepsis, Septic Joint, Bacterial Meningitis, Appendicitis, Diverticulitis, occult Bacterial Infection
    2. CBC is the “Last Bastion of the Intellectually Destitute” (Amal Mattu)
  2. References
    1. Cruz (2017) JAMA Pediatr 171(11):e172927 +PMID: 28892537 [PubMed]
    2. Pediatric EM Morsels (Fox)
      1. https://pedemmorsels.com/wbc-count-fever/
  • Physiology
  1. See Bone Marrow
  2. Bone Marrow produces stem cell lines
    1. Images
      1. HemeBloodCellOrigin.jpg
    2. Myeloid lines
      1. Erythroblasts (develop into erythrocytes)
      2. Myeloblasts (develop into Granulocytes)
      3. Megakaryocyte (develop into Platelets)
    3. Lymphocytic lines
      1. Lymphoblasts (develop into Lymphocytes)
  • Technique
  • Specimen
  1. Specimen rejected if clotted
    1. Immediately mix specimen 10 times by gently inversion
  2. Tube type: Lavender or Purple Top
  3. Volume
    1. Adults: 3 ml (1 ml minimum)
    2. Children: 1 ml (0.3 ml in pediatric micro-container)
  • Lab
  • Components
  1. White Blood Cell Count
    1. Neutrophil Count
    2. Lymphocyte Count
    3. Eosinophil Count
    4. Basophil Count
    5. Monocyte Count
  2. Red Blood Cell Count
  3. Hemoglobin
  4. Hematocrit
  5. Erythrocyte Indices
    1. Mean Corpuscular Volume
    2. Mean Corpuscular Hemoglobin Concentration (MCHC)
    3. Mean Corpuscular Hemoglobin
  6. Red Cell Distribution Width
  7. Platelet Count