Urine cortisol:creatinine ratio in healthy and sick cats.

Urine cortisol:creatinine ratios (UCCR) were determined from single urine samples obtained by cystocentesis in 47 cats allotted into 2 groups: 31 healthy cats and 16 sick, hospitalized cats with assorted clinical illnesses. The mean (+/- standard deviation) UCCR for healthy cats was 5.9 +/- 7.0 (median, 3.2; range, 0.6 to 27.8). Age or gonadal status had no significant effect on the magnitude of UCCR within this group. However, sick cats had significantly higher UCCR (P = .002) when compared with healthy cats. The mean UCCR for sick cats was 19.6 +/- 19.2 (median, 14.8; range, 1.7 to 75.1). This report establishes a reference range for UCCR in 31 normal cats and provides evidence that health status affects UCCR in cats.