AVP and systemic inflammatory response syndrome: Copeptin levels increased with disease severity from systemic inflammatory response syndrome to sepsis and severe sepsis to septic shock- copeptin levels in non-survivors, 171.5 pmol/L versus survivors, 86.8 pmol/L, P < 0.001- predictive of mortality (AUC 0.75)- optimal prognostic accuracy of copeptin at 96 pmol/L; sensitivity, 61.5%, specificity 83.8%