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Test Findings


March 30th, 2020


Anisocytosis refers to increased variability of red blood cell size. Red cells are normally of uniform size, and significant variation
  • Look For

  • Elevated Red cell distribution width (RDW) on full blood count
  • Variability in red blood cell size on blood film
Anisocytosis may be caused by any condition that results in microcytosis or macrocytosis.
For example, a patient with early megaloblastic anaemia may have a mix of macrocytes and normally sized cells, resulting in an overall normal mean red cell volume (MCV) with anisocytosis.
  • Interpretation

  • More microcytic - suggests iron deficiency or sideroblastic anaemia
  • More normocytic - suggests early iron deficiency or megaloblastic anaemia, reticulocytosis (haemolysis, recovery following haemorrhage or bone suppression) or sickle cell anaemia
  • More macrocytic - suggests megaloblastic anaemia, myelodysplastic syndrome or chronic liver disease
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