Alkaline phosphatase activity in airway fluid obtained by tracheal wash from adult horses.

Background: Collection of fluid from the lower respiratory tract (LRT) plays an important role in both the pathophysiological investigation and diagnosis of respiratory tract disease. Enzymes such as ALP are, among others, indicators of cell damage or death, type II pneumocyte proliferation, and neutrophil invasion, and have been useful as biomarkers of respiratory disease in other species.

Objectives: The purpose of this study was to determine and compare tracheal wash (TW) ALP activity in healthy horses and horses with LRT inflammation (LRTI) determined by TW cytology profile.