Effects of different drying methods on smears of canine blood and effusion fluid

Abstract

Background Glass slide preparations from a variety of specimens (blood, masses, effusions) are commonly made as part of the diagnostic work-up, however the effects of various drying methods in veterinary practice and diagnostic laboratory settings is not clear. Objective Compare the effects of four drying methods on results of microscopic examination of canine blood smears and direct smears of pleural or peritoneal effusion fluid. Methods Twelve canine blood samples (6 from healthy dogs, 6 from sick dogs) and 6 canine peritoneal or pleural effusion samples. Four smears were prepared from each of the 18 samples and dried using the following methods: air-dry, hair dryer with or without heat, and heat block at 58 °C. Observers, blinded to the drying method, independently reviewed the slides microscopically, using a scoring system to evaluate cell morphology and (for blood smears) echinocyte numbers; scoring results were analyzed statistically. Results For blood smears, several comparisons showed more adverse effects on morphology using the heat block method than for one or more other drying methods. For effusion fluid smears, RBCs dried with the heat block or air-dry methods had more poorly preserved morphology than RBCs dried by the hair dryer method without heat. Conclusions and clinical relevance The results (1) indicate that different drying methods had a significant effect, (2) support using a hair dryer without heat for both blood smears and effusion fluid smears, and (3) discourage using a 58 °C heat block.

Successful treatment of pyruvate kinase deficiency and inflammatory bowel disease comorbid with exocrine pancreatic insufficiency and hypocobalaminaemia in a cat

“…Remarkably, however, repeat prescription of prednisolone after splenectomy significantly improved the HCT concentration, RBC morphology and the presence of echinocytes (Table 1, Figures 1 and 2). Because echinocytes can be an artefactual finding, all blood smears were stained at blood collection to prevent artefacts 12 . Moreover, evaluating the average number and percentage of echinocytes in blood smears provides meaningful results 12 .…”

“…Because echinocytes can be an artefactual finding, all blood smears were stained at blood collection to prevent artefacts 12 . Moreover, evaluating the average number and percentage of echinocytes in blood smears provides meaningful results 12 . Thus, genuine echinocytes were thought to be evaluated adequately, and a combination of prednisolone and splenectomy appears to be an effective treatment for PK deficiency in cats, despite a confounding factor such as chronic inflammation arising from IBD contributing to anaemia.…”