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Hematologic Findings For Various Types of Beta Thalassemia

Beta Thalassemia Minima

Beta Thalassemia MinorBeta Thalassemia Intermedia Beta Thalassemia Major

Delta-Beta Thalassemia

AnemiaAbsentMild to absentModerateSevereMild

Red blood cell (RBC) count

NormalIncreasedDecreased to normalDecreasedDecreased to normal

Hemoglobin(Hb)

NormalDecreased to normal (10 - 12 g/dL) Decreased (7 - 10 g/dL)Marked decrease (<7 g/dL)

Decreased to normal (8 - 13 g/dL)

Mean corpuscular volume (MCV)Slight to no decreaseMarked decreaseMarked decreaseMarked decreaseMay be slightly decreased
Mean corpuscular hemoglobin concentration (MCHC)Slight to no decreaseMarked decrease Marked decreaseMarked decreaseMay be slightly decreased
Red blood cell distribution width (RDW)NormalNormal to slightly increasedIncreasedIncreasedNormal
RBC morphologyNormal
  • Marked hypochromia and microcytosis
  • Codocytes (target cells)
  • Possible basophilic stippling

Nucleated RBCs are usually not present

  • Marked hypochromia and microcytosis
  • Codocytes (target cells)
  • Possible basophilic stippling

Nucleated RBCs are usually not present

  • Marked hypochromia and microcytosis
  • Codocytes (target cells)
  • schistocytes
  • ovalocytes
  • basophilic stippling
  • polychromasia
  • nucleated RBCs
  • Possible hypochromia and microcytosis
  • Codocytes (target cells)
  • Basophilic stippling
Reticulocyte countNormalMay be slightly increasedSlightly increased (<5%)Mildly increased (5 - 10%)Mildly increased
Hb electrophoresisNormal pattern
  • Decreased amount of Hb A
  • Variable amounts of Hb A2 and Hb F
  • Decreased amount of Hb A
  • Variable amount of Hb A2
  • Hb F is usually increased
  • Severly decreased amount of Hb A
  • Variable amount of Hb A2
  • Usually an increased amount of Hb F

Decreased amount of Hb A and Hb A2

Increased amount of Hb F (15 - 20%)

If red blood cells are normochromic and normocytic, the RBC, Hb, and Hematocrit (HCT) test values follow in three-fold progression (i.e., RBC x 3 = Hb and Hb x 3 = HCT). This is sometimes referred to as "the rule of threes." This rule will usually not apply in cases of beta thalassemia, particularly beta thalassemia minor where the RBCs are not normochromic and are microcytic, and where there is a disproportionate number of RBCs for the amount of hemoglobin that is present.