Another study also found random copeptin levels >20 pmol/l as good cut-offs for AVP resistance, with post-overnight water deprivation levels of <2.6 pmol/l indicating AVP deficiency (diagnostic accuracy of 78%), and a ratio of Δplasma copeptin levels before and after water deprivation to plasma sodium post water deprivation had a high diagnostic accuracy of 94% for AVP deficiency (3). The gene discussed is AVP; the disease is neurohypophyseal diabetes insipidus.