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Veterinary Medicine International
Volume 2014 (2014), Article ID 409573, 10 pages
Research Article

Retrospective and Prospective Investigations about “Quatrefoil” Erythrocytes in Canine Blood Smears

1Department of Veterinary Sciences, University of Pisa, via Livornese Lato Monte, San Piero a Grado, 56124 Pisa, Italy
2Department of Comparative Biomedical Sciences, University of Teramo, Piazza Aldo Moro 45, 64100 Teramo, Italy

Received 26 August 2013; Revised 7 October 2013; Accepted 7 October 2013; Published 6 January 2014

Academic Editor: Francesca Mancianti

Copyright © 2014 Alessandra Gavazza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The presence of unusual two RBCs patterns (so-called “quatrefoil RBCs,” qRBCs) on canine blood smears at Optical Microscope (OM) was seen during routine evaluation of CBCs. Two consecutive retrospective investigations were arranged including about 7,000 CBCs and clinical records and laboratory data from dogs showing qRBCs. Few samples with qRBCs were prepared for Scanning Electron Microscope (SEM). qRBCs were found in 6.89% (139 of 2016) and 8.47% (133 of 1569) of dogs and in 3.89% (154 of 3,958) and 4.47% (138 of 3,081) of CBCs (some dogs were tested more than once). Statistical analysis was significant for age groups (Chi squared, ), decreased total leukocyte and neutrophil counts (ANOVA, ), RBCs anisocytosis, polychromasia, and Howell-Jolly bodies (ANOVA, , <0.005, and <0.003, respectively). qRBCs were distributed in the area of feathered edge and at the smear side of body-feathered edge area in blood films. SEM ruled out the possibility of an optical illusion or an accidental overlap. qRBCs are associated with ageing of dogs, total leukocyte and neutrophil counts, and RBC anisocytosis, polychromasia, and Howell-Jolly bodies. Few hypotheses were discussed to explain the origin and meaning of this RBC arrangement.