NM01 - Effect of Fasting versus Feeding on Selected Biochemical Analytes in 100 Healthy Dogs

Abstract: Background – Fasting is often recommended prior to the collection of blood for routine biochemical analysis despite a paucity of evidence to support this requirement.
Objectives – To compare measurements of selected biochemical analytes collected before and after feeding in clinically healthy dogs.
Animals – 100 clinically healthy dogs weighing >15 kg.
Methods – Prospective observational study. Food was withheld for at least 10 hours. Preprandial serum was collected, and then dogs were fed their usual food at an amount equivalent to at least 2/3 resting energy requirement. Serum was collected at 2-, 4-, 6-, and 8-hours postprandially. The proportion of postprandial values that exceeded either the reported total allowable error (TEa), or for SDMA, the reference change value (RCV), was determined.
Results -The proportion of dogs with postprandial measurements that exceeded the TEa or RCV was 92/100 for triglycerides, 66/100 for BUN, 17/100 for glucose, 46/100 for phosphorus, 9/100 for bilirubin, 5/100 for SDMA, 2/100 for creatinine, and 0/100 for cholesterol and albumin. Of dogs with a postprandial result above the upper end of the reference interval, the proportion that had a fasted measurement above the reference interval was 3/36 for triglycerides, 7/17 for SDMA, 2/3 for creatinine, 8/10 for cholesterol, and 0/6 for glucose. Albumin and BUN never exceeded the reference interval, nor did postprandial lipase in dogs with normal fasted lipase.
Conclusions and clinical importance – Certain biochemical analytes may be impacted by feeding in healthy dogs. The impact in patients with illness requires investigation.