Table 1.

Reference intervals for serum concentrations of urea nitrogen, creatinine, and symmetric dimethylarginine (SDMA) based on results from 206 clinically normal, older cats. The 90% confidence intervals (CI) are calculated for both the lower and upper limits of each reference interval

Analyte	Lower Reference Limit	90% CI	Upper Reference Limit	90% CI
Urea nitrogen (mg/dL)	17	15–18	39	37–39
Creatinine (mg/dL)	0.8	0.8–0.9	2.1	2.0–2.1
SDMA (μg/dL)	5	3–6	14	14–15