Leukaemoid reaction


Appropriate Tests


Extreme peripheral blood leucocytosis (usually >50x 10^9/L), often with immature white cells, and a superficial resemblance to leukaemia.

Review clinical features, Full blood count, Blood film, White cell count differential; consult haematpathologist.

See also Table 4, Neutrophilia, Neutrophilia with early myeloid cells (Blood film)

Myeloid reaction


Carcinoma, especially advanced and/or metastatic


Severe/chronic often bacterial infection

  • Abscess
  • Tuberculosis


Cytokine therapy, especially G-CSF


Recovery from bone marrow aplasia/hypoplasia


Lymphoid reaction




Infectious mononucleosis


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