Pseudoeosinophilia associated with malaria infection determined in the Sysmex XE-2100 hematology analyzer

Ann Hematol. 2005 Jun;84(6):400-2. doi: 10.1007/s00277-004-0987-z. Epub 2004 Dec 23.

Abstract

Hemozoin is known to be an end product of hemoglobin digestion by the malaria parasite. Hemozoin is a birefringent crystal, and thus hemozoin-containing white blood cells (WBCs) may show the atypical light scattering pattern. The purpose of this study was to investigate pseudoeosinophilia associated with malaria infection using a Sysmex XE-2100 hematology analyzer (Sysmex Corporation, Kobe, Japan). The study group included 16 patients with malaria infection. Of these, 38% showed erroneously high eosinophil counts and atypical eosinophil distributions in the WBCs scattergram, which was due to the presence of hemozoin-containing neutrophils. In two patients, their erroneously high eosinophil counts declined as the parasitemia decreased with treatment. In conclusion, hematologists should consider the possibility of pseudoeosinophilia as a result of hemozoin-containing WBCs and confirm the WBC differential count by microscopy in cases of malaria infection.

MeSH terms

  • Adult
  • Artifacts*
  • Birefringence
  • Eosinophilia / diagnosis*
  • False Positive Reactions
  • Female
  • Hemeproteins / analysis*
  • Hemeproteins / chemistry
  • Humans
  • Leukocyte Count / instrumentation*
  • Light
  • Malaria, Vivax / blood*
  • Male
  • Middle Aged
  • Neutrophils / chemistry*
  • Parasitemia / blood*
  • Scattering, Radiation

Substances

  • Hemeproteins
  • hemozoin