Background: There is a need for a clinically useful, quantitative index for measurement of disease activity in cats with chronic enteropathy (CE).

Objective: To develop a numerical activity index that is of practical value to clinicians treating CE in cats.

Animals: Eighty-two cats with CE.

Methods: Retrospective case review of 59 cats diagnosed with inflammatory bowel disease (IBD). Prospective validation study of 23 cats having either IBD or food-responsive enteropathy (FRE). Multivariate regression analysis was used to identify which combination of clinical and laboratory variables were best associated with intestinal inflammation of IBD. This combination of variables was expressed in a score that was used as an activity index for the prospective assessment of disease activity and of the effect of treatment in cats with IBD or FRE.

Results: The combination of gastrointestinal signs, endoscopic abnormalities, serum total protein, serum alanine transaminase/alkaline phosphatase activity, and serum phosphorous concentration had the best correlation with histopathologic inflammation and comprise the feline chronic enteropathy activity index (FCEAI). Positive treatment responses in cats with CE were accompanied by significant (P < .05) reductions in FCEAI scores after treatment.

Conclusions and Clinical Importance: The FCEAI is a simple numerical measure of inflammatory activity in cats with CE. The scoring index can be reliably used in the initial assessment of disease severity for both IBD and FRE and as a measure of clinical response to treatment for these disorders.