Teschner et al. [19] used the method developed by Rieger et al. [18], reporting that PCT concentrations were quite high in horses that have colic due to endotoxemia with respect to control group (23,532.4 vs. 385.3 ng/mL); this method has been used by Barton et al. [20] to measure PCT in bronco alveolar fluid (BALF), showing that PCT level increased in horses with chronic pneumopathies and there was a correlation between plasma and BALF PCT. Here, CALCA is linked to serum lipopolysaccharide activity.