Diagnostic effectiveness of stress biomarkers in cats with feline interstitial and bacterial cystitis.

High urine serotonin concentrations were found in cats with FLUTD compared with healthy controls and interpreted as the presence of stress not only in cats with FIC but also in cats with BC. Also, based on the ROC-based diagnostic performance evaluation of these stress biomarkers, urine serotonin, and dopamine concentrations can be used to diagnose FIC, and serum dopamine concentrations can be used to differentiate FIC and BC in cats.