White Blood Cell Disorders and Platelets:: 1. Leukemoid Reaction vs Toxic Changes

Leukemoid reaction revisited

  • The term leukemoid reaction is used to describe peripheral white blood cells that on the stained blood smear may have some resemblances to leukemia cells.
  • Quantatively in a leukemoid reaction, the neutrophil count is >50,000 cumm with more immature cells, particularly myelocytes, than are usually present in toxic left shift syndromes. The presence of immature cells in a leukemoid reaction awakens thoughts of leukemia. Great care must be taken to make a distinct differentiation between aberrant white blood cell proliferations and a benign but exaggerated granulocytic proliferative response.
  • Our material is from a 1-month-old girl with Down's syndrome. Her total white blood count was 37,000/mm3 interpreted as leukocytosis with left shift.
  • Leukocytosis with a left shift, and leukemoid reactions with high alkaline phosphatase are conditions to be mindful of in patients with Down's syndrome.
  • The alkaline phosphatase score is high in leukemoid reactions, low in granulocytic leukemia.

Earn ASCLS P.A.C.E.® credits for your AMT, ASCP, or NCA recertification requirements.

White Cell and Platelet Disorders: Peripheral Blood Clues to Nonneoplastic Conditions course details »

Learn more about medical technologist continuing education for MTs, MLTs, and other lab personnel »

Get information on laboratory compliance training for clinical and medical laboratories »