Lab

Red Cell Distribution Width

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Red Cell Distribution Width, RDW

  1. Iron Deficiency Anemia from other Microcytic Anemias
  2. May increase before MCV becomes abnormal
  • Definition
  1. Measures size variability of Red Blood Cell population
  • Normal
  1. Range: 11.5-14.5%
  • Normal Red Cell Distribution Width (RDW)
  1. Mean Corpuscular Volume (MCV) Increased
    1. Aplastic Anemia
    2. Pre-Leukemia
  2. Mean Corpuscular Volume (MCV) Normal
    1. Anemia of Chronic Disease
    2. Acute blood loss
    3. Hemolysis
    4. Chronic Lymphocytic Leukemia (CLL)
    5. Chronic Myelogenous Leukemia (CML)
    6. Hemoglobinopathy
    7. Normal variant
  3. Mean Corpuscular Volume (MCV) Decreased
    1. Anemia of Chronic Disease
    2. Thalassemia (Heterozygous)
  • Increased Red Cell Distribution Width (RDW)
  1. Mean Corpuscular Volume (MCV) Increased
    1. Vitamin B12 Deficiency
    2. Folate Deficiency
    3. Immune Hemolytic Anemia
    4. Liver disease
  2. Mean Corpuscular Volume (MCV) Normal
    1. RDW increases before MCV becomes abnormal
      1. Early Iron Deficiency Anemia
      2. Early Vitamin B12 Deficiency
      3. Early Folate Deficiency
    2. Anemic globinopathy
  3. Mean Corpuscular Volume (MCV) Decreased
    1. Iron Deficiency Anemia
    2. RBC fragmentation
    3. HbH
    4. Thalassemia intermedia