Copeptin levels increased with increasing severity of LRTI, as classified by the Pneumonia Severity Index- predictive of mortality (AUC 0.75)- copeptin levels in survivors 24.3 pmol/L (normal: 10.8 to 43.8 pmol/L), versus 70.0 pmol/L (normal: 28.8 to 149 pmol/L) in non-survivors- optimal threshold of copeptin, 53 pmol/L; sensitivity to correctly predict mortality, 58% with a specificity of 80%; LR+ 3.0, LR- 0.5 The gene discussed is AVP; the disease is susceptibility to pneumonia measurement.