Artifactual changes in PCV, hemoglobin concentration, and cell counts in bovine, caprine, and porcine blood stored at room and refrigerator temperatures John I. Ihedioha, Rebecca C. Onwubuche Background: Blood samples collected from farm animals for hematology testing may not reach the laboratory or be examined immediately upon collection, and in some cases may need to be transported for hours before reaching a laboratory. Objective: The objective of this study was to investigate the artifactual changes that may occur in PCV, hemoglobin (Hgb) concentration, and cell counts in bovine, caprine, and porcine blood samples stored at room (308C) or refrigerator (58C) temperature. Methods: Baseline values for PCV, Hgb concentration, and RBC and WBC counts were determined immediately after blood collection from 36 cattle, 32 goats, and 48 pigs using manual techniques. Blood samples were split into 2 aliquots and stored at 308C or 58C. Hematologic analyses were carried out at specified intervals during 120 hours of storage. Results were analyzed by repeated measure ANOVA; results at different temperatures were compared by paired t-tests. Results: Compared to baseline values, there were no significant changes in Hgb concentration, RBC count, or WBC count in samples from cattle; in Hgb concentration and RBC count in samples from goats; and in Hgb concentration and WBC count in samples from pigs throughout the 120 hours of storage at both 308C and 58C. Significant changes (P , .05) from baseline occurred in PCV after 14 hours of storage at 308C and after 19 hours of storage at 58C in cattle and goats; and after 10 hours of storage at 308C and 14 hours of storage at 58C in pigs. Significant changes also were observed in Hgb concentration at 96 hours at 308C and 58C, and in RBC counts at 48 hours at 308C and 96 hours at 58C in porcine samples; and in total WBC counts at 120 hours at 308C and 58C in caprine samples. Artifactual changes were more pronounced in the samples stored at 308C. Conclusions: At both 308C and 58C, blood samples from cattle and goats can be stored for up to 12 hours, while blood samples from pigs can be stored for up to 8 hours without any significant changes in PCV. Blood samples from all 3 species can be stored for more than 24 hours without significant changes in Hgb concentration, RBC count, and total WBC count. (Vet Clin Pathol. 2007;36:60–63) Ó2007 American Society for Veterinary Clinical Pathology Key Words: Artifactual changes, blood, cattle, pig, goat, preanalytical error, storage, temperature u The method of storage and handling of blood samples between the time of collection from an animal and the time of evaluation in the laboratory can strongly influence the results obtained from hematologic determinations; misleading results could be generated from blood samples that are improperly stored or handled. 1,2 It is therefore routinely re- commended that hematologic determinations on blood sam- ples should be carried out immediately after blood collection, and if not immediately possible, the sample should be stored in a refrigerator until determinations can be carried out in order to minimize artifactual changes. 1–4 However, the field veterinarian (especially in developing countries) is often faced with situations in which blood samples have to be collected from farm animals at remote farms or farm settlements where power supply, refrigerators, and standard laboratory facilities may either be unavailable or nonfunctional, and blood samples will need to be transported unrefrigerated for hours before reaching a laboratory that is most often located in an urban area. Sometimes, the time spent collecting samples from a large number of animals may contribute to delay in moving the samples to a laboratory. Even upon arrival at a laboratory, hematologic evaluations may be further delayed, especially when automated hematology analyzers are unavailable, manual procedures have to be followed, and the samples are large in number. There have been no reports (known to the authors) of studies on artifactual hematologic changes in bovine, caprine, and porcine blood samples stored at either refrigerator or room temperature. Most of the earlier studies on the arti- factual hematologic changes in blood of humans and some other animal species showed that storage at refrigerator temperature (48C) stabilizes blood specimens and leads to relatively fewer artifactual changes than storage at room temperature (22–258C). 2–4 However, studies on equine blood by Clarke et al 5 showed that artifactual hematologic changes were less pronounced in equine blood samples stored at room From the Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, University of Nigeria, Nsukka, Enugu State, Nigeria. Corresponding author: John I. Ihedioha (jiiferh@yahoo.com). ª2007 American Society for Veterinary Clinical Pathology Page 60 Veterinary Clinical Pathology Vol. 36 / No. 1 / 2007