title: Spurious reticulocyte profiles in a dog with babesiosis.
abstract: A 9-year-old, female Maltese dog was referred to the Veterinary School of Toulouse with a 2-day history of anorexia and weakness. On clinical examination, the dog had hyperthermia (39.7°C), abdominal discomfort, and polypnea. Significant laboratory findings included pigmenturia, hyperbilirubinemia, hypercreatininemia, hyperfibrinogenemia, abnormal Snap canine pancreas-specific lipase, and pancytopenia with a nonregenerative anemia. A peripheral blood smear revealed numerous intraerythrocytic large Babesia but no polychromasia. There was a discrepancy between the absolute automated reticulocyte count (Sysmex reticulocyte count: 60 × 109/L; RI 19.4-150.1 × 109/L) and the manual reticulocyte count (3.6 × 109/L) as well as the absence of polychromasia. The optical red blood cell scattergram showed an abnormal isolated reticulocyte cluster at the location of low-fluorescence ratio cells. These findings were interpreted as erythrocytes parasitized by large Babesia. The discrepancy between the Sysmex reticulocyte count and the manual reticulocyte count has been reported previously in people with falciparum malaria and numerous intra-erythrocytic Plasmodium falciparum organisms. This spurious reticulocyte profile and reticulocyte count were observed with the Sysmex XT-2000iV and the ProCyte using the same fluorescent dye polymethine but not with the LaserCyte using new methylene blue which does not stain Babesia organisms on a blood smear performed for manual reticulocyte counting.
authors.affiliation: Equipe de Biologie Médicale-Histologie, CREFRE, INSERM, UPS, ENVT, Université de Toulouse, Toulouse, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Piane
authors.affiliation: Unité d'Urgence et soins intensifs, UPS, INP, ENVT, Université de Toulouse, Toulouse, France.
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Théron
authors.affiliation: Unité d'Urgence et soins intensifs, UPS, INP, ENVT, Université de Toulouse, Toulouse, France.
authors.forename: Marcel
authors.initials: M
authors.lastname: Aumann
authors.affiliation: Equipe de Biologie Médicale-Histologie, CREFRE, INSERM, UPS, ENVT, Université de Toulouse, Toulouse, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Trumel
mesh_terms: D000818:Animals; D001403:Babesia / Q000302:isolation & purification*; D001404:Babesiosis / Q000097:blood* / Q000469:parasitology / Q000473:pathology; D001772:Blood Cell Count / Q000295:instrumentation / Q000662:veterinary; D004283:Dog Diseases / Q000097:blood* / Q000469:parasitology / Q000473:pathology; D004285:Dogs; D004912:Erythrocytes / Q000469:parasitology / Q000473:pathology; D005260:Female; D017701:Reticulocyte Count / Q000295:instrumentation / Q000662:veterinary; D012156:Reticulocytes / Q000469:parasitology / Q000473:pathology*
keywords: Babesia; pseudoreticulocytosis; reticulocyte fluorescence ratios; scattergram