Serum constituents analyses in dairy cows: Effects of duration and temperature of the storage of clotted blood A. Ehsani, A. Afshari, H. Bahadori, M. Mohri, H.A. Seifi * Center of Excellence in Ruminant Abortion and Neonatal Mortality, School of Veterinary Medicine, Ferdowsi University of Mashhad, P.O. Box 1793-91775, Mashhad, Iran Accepted 6 February 2008 Abstract We studied the effects of storage time and temperature of clotted whole blood on the amounts of 17 analytes in bovine blood serum. Serum separated after blood was allowed to stand for 2, 4, 6, 12 and 24 h at room temperature or on ice. Results obtained for phosphorous, magnesium, urea, cholesterol, b-hydroxybutyrate (BHBA), triglyceride, albumin, total protein and c-glutamyletransferase (GGT) were not influenced by storage at room temperature or on ice for as long as 24 h. Duration of the clotted whole blood storage had a significant effect on calcium, glucose concentrations, creatine kinase (CK) and aspartate aminotransferase (AST) activities and temperature had a significant effect on glucose, non-esterified fatty acids, CK and bilirubin concentrations. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Biochemistry; Clotted blood; Storage; Dairy cow Proper blood sample processing and handling is required in order to obtain reliable biochemical measure- ments. Temperature and duration of whole blood storage can affect some biochemical constituents. To have minimal changes in the actual concentrations of blood biochemical constituents, it is a standard practice to separate serum from the blood clot by centrifugation as soon as the clot forms. The effect of storage temperature and time to sepa- rating serum from blood clot on few blood analytes was studied in different species (Ono et al., 1981; Stokol and Nydam, 2005). Significant changes were seen for total pro- tein, calcium, AST and glucose between 2 and 24 h at 23 °C (Ono et al., 1981). In veterinary medicine, to date very little has been pub- lished on the stability in whole blood and of many bio- chemical markers. The issue is important, because in large epidemiological studies it is often not feasible to cen- trifuge and freeze blood samples immediately after veni- puncture especially in cattle. This study was done to provide recommendations to dairy practitioners and researchers on how long and how best to store the clotted blood samples before serum sepa- ration for most common biochemical analytes to obtain accurate results in dairy cattle. Twelve adult Holstein dairy cows from a herd were recruited and the sampled blood from each individual cow via jugular venipuncture (using 18 gauge needles) was divided into 12 plain tubes (totally, 144 samples were used). Six tubes were stored at room temperature (23 ± 2 °C) and another six tubes were stored on ice (4 ± 2 °C) immediately after sampling. The specimens were transported to the laboratory and maintained as whole blood. At 2, 4, 6, 12 and 24 h from the initial zero time sampling, two aliquots from each temperature were centri- fuged at 1800 g for 10 min, and the separated sera were kept frozen at À20 °C until assay. Harvested sera were analyzed for the determination of glucose (glucose oxidase), cholesterol (CHOD-PAP), 0034-5288/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.rvsc.2008.02.004 * Corresponding author. Tel.: +98 915 311 4355; fax: +98 511 8763852. E-mail address: haseifi@ferdowsi.um.ac.ir (H.A. Seifi). www.elsevier.com/locate/rvsc Available online at www.sciencedirect.com Research in Veterinary Science 85 (2008) 473–475