RESUMO
Preanalytical factors such as storage time and temperature are proved to induce marked artifactual changes in hematological parameters in horses, small animals and humans. These errors can mirror findings typical of endotoxemia, leading to dangerous misdiagnosis. Since donkeys are common in warm climates and remote regions, blood samples from this species can be subjected to long lasting travels from the farm to the nearest laboratory, frequently under suboptimal conditions. Moreover, as other equids, donkeys are prone to suffer endotoxemia. Nonetheless, stability has not been evaluated in samples for hematology in this species. The aim of this study was to characterize the effect of temperature and storage time in hematological parameters from healthy donkeys and donkeys with induced endotoxemia. Blood samples were collected from six healthy female Andalusian donkeys and stored for 6, 12, 24, and 48 h at several temperatures (4, 24, and 35°C). Endotoxemia was induced in the same animals by an intravenous LPS infusion and samples obtained 30 min post-infusion were handled similarly. Hematological analysis was performed using a laser-based analyzer and blood smear examination. Storage at 24°C caused significant neutropenia after 48 h as well as morphological changes typical of endotoxemia in blood from healthy donkeys as soon as 24 h post-storage. Samples kept at 35°C displayed more profound and earlier artifactual variations. Conservation at 4°C did not cause any significant change in blood parameters. Prolonged (48 h) storage of samples from animals with induced endotoxemia at 24 and 35°C accentuated pre-existing leukopenia and neutropenia. These findings highlight that donkey samples should be stored at 4°C, instead of 24°C as recommended for horses. Moreover, blood smear interpretation should be cautious in samples stored for longer than 24 h and could be misleading when blood is kept at 35°C.
RESUMO
BACKGROUND: Donkeys are becoming increasingly important worldwide; therefore a reliable and accurate method of diagnosing disease is necessary. Flow cytometry-based hematologic analyzers are present in veterinary laboratories, but performance of LaserCyte has not been evaluated in donkeys. OBJECTIVES: The objective of the study was to compare the results of donkey blood obtained from the LaserCyte with impedance and manual methods. METHODS: Blood samples were collected from 84 healthy donkeys (1-20 years old) and measured with LaserCyte, Sysmex F-820 and manually. Agreement between methods was studied using Passing-Bablok test and Bland-Altman plots. Influence of blood abnormalities found on blood smears on LaserCyte counts was examined using Mann-Whitney or Kruskal-Wallis test. Intraassay precision was calculated. RESULTS: Hematologic variables obtained from the LaserCyte were significantly different from those obtained with impedance or manual methods; numerous values were flagged. Agreement between LaserCyte and manual method was poor for the majority of variables, but agreement between LaserCyte and impedance was only poor for HCT, MCH, and MCHC. LaserCyte had an intraassay precision < 10% for RBC and platelet variables, and > 10% for WBC variables. CONCLUSIONS: LaserCyte results were not interchangeable with results from other methods due to poor agreement. LaserCyte provided no additional hematologic variables or clinically relevant indices for donkey blood analysis. A large number of results were flagged, requiring the evaluation of blood smears. No benefits were found for the use of LaserCyte analyzer over the use of impedance or manual methods in this study. Specific software for LaserCyte for donkey blood would be beneficial.