Dual population

• Finding on peripheral blood film showing two different types of red blood cell, usually including populations that are normocytic & normochromic, microcytic & hypochromic, or macrocytic & normochromic
• Causes include:
  • Sideroblastic anemia
  • Myelodysplastic syndrome
  • Iron deficiency
  • Vitamin B12 deficiency
  • Folate deficiency
  • Exogenous use of erythropoietin
  • Red blood cell transfusion