HMGB1 and systemic inflammatory response syndrome: The optimal serum HMGB1 cut-off between SIRS and non-SIRS dogs with AP was determined graphically to be 0.35 ng/mL, with the area under the curve being 0.82, the sensitivity 87.5% (95% CI = 47.35–99.68%), and the specificity 71.4% (95% CI = 41.90–91.61%).