Table 2.

Summary of SIAD subtype definition in response to 3% NaCl infusion

SIAD SubtypeDefinition
APlasma copeptin consistently >38 pmol/L with a copeptin slope <95% CI for that of healthy persons (i.e., <0.66 pmol/L/mOsM/kg H2O)
BAny plasma copeptin concentration with a positive copeptin slope >0.25 pmol/L/mOsM/kg H2O, but a low osmotic threshold <95% CI for that of healthy persons (i.e., <281 mOsM/kg H2O)
CPlasma copeptin concentration between 2 and 38 pmol/L with a copeptin slope between −0.25 and 0.25 pmol/L/mOsM/kg H2O
DPlasma copeptin concentration consistently <2 pmol/L regardless of the copeptin slope
EAny plasma copeptin concentration with a copeptin slope <−0.25 pmol/L/mOsM/kg H2O