title: Pseudoeosinophilia associated with malaria infection determined in the Sysmex XE-2100 hematology analyzer.
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.
authors.affiliation: Department of Laboratory Medicine, College of Medicine, Mokdong Hospital, Ewha Womans University, Mokdong 911-1, Yangcheon-Gu, Seoul, South Korea, 158-710. JungWonH@hitel.net
authors.forename: Jungwon
authors.initials: J
authors.lastname: Huh
authors.forename: Junseop
authors.initials: J
authors.lastname: Jung
authors.forename: Hyungdu
authors.initials: H
authors.lastname: Yoon
authors.forename: Whasoon
authors.initials: W
authors.lastname: Chung
mesh_terms: D000328:Adult; D016477:Artifacts; D001718:Birefringence; D004802:Eosinophilia / Q000175:diagnosis*; D005189:False Positive Reactions; D005260:Female; D006420:Hemeproteins / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D007958:Leukocyte Count / Q000295:instrumentation*; D008027:Light; D016780:Malaria, Vivax / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000737:chemistry*; D018512:Parasitemia / Q000097:blood*; D012542:Scattering, Radiation
chemical_list: D006420:Hemeproteins; C020753:hemozoin