Influence of veterinary care on the urinary corticoid: Creatinine ratio indogs

Physical and emotional stresses are known to increase the production and se cretion of glucocorticoids by the adrenal cortex in both humans and experim ental animals. The urinary corticoid:creatinine (C:C) ratio is increasingly used as a measure of adrenocortical function. In this study we investigate d whether a visit to a veterinary practice for vaccination, a visit to a re ferral clinic for orthopedic examination, or hospitalization in a referral clinic for 1.5 days resulted in increases of the urinary C:C ratio in pet d ogs. In experiment I, owners collected voided urine samples from 19 healthy pet dogs at specified times before and after taking the dogs to a veterina ry practice for yearly vaccination. In experiment 2, 12 pet dogs were evalu ated in a similar way before and after an orthopedic examination at a refer ral clinic. In experiment 3, 9 healthy pet dogs were hospitalized for 1.5 d ays and urine samples were collected before, during, and after this stay. B asal urinary C:C ratios in all experiments ranged from 0.8 to 8.3 x 10(-6). In experiment I, the urinary C:C ratio after the visit to the veterinary p ractice ranged from 0.9 to 22.0 x 10(-6). Six dogs had a significantly incr eased urinary C:C ratio (responders), but in 5 of these dogs the ratio was less than or equal to 10 x 10(-6). Tn experiment 2, 8 of 12 dogs responded significantly with urinary C:C ratios ranging from 3.1 to 27.0 x 10(-6). In experiment 3, 8 of 9 dogs had significantly increased urinary C:C ratios, ranging from 2.4 to 24.0 x 10(-6), in some or all urine samples collected d uring hospitalization. In 4 dogs urinary C:C ratios 12 hours after hospital ization were still significantly higher than the initial values. Thus, a vi sit to a veterinary practice, an orthopedic examination in a referral clini c, and hospitalization can be considered stressful conditions for dogs. A l arge variation occurs in response, and in individual dogs the increases in urinary C:C ratios can exceed the cutoff level for the diagnosis of hyperad renocorticism. Therefore, urine samples for measurement of the C:C ratio in the diagnosis of hyperadrenocorticism should be collected in the dog's hom e environment, to avoid the influence of stress on glucocorticoid secretion .