also assessed the copeptin-based glucagon stimulation test and found that glucagon-stimulated copeptin in healthy participants, using a copeptin cut-off level of 4.6 pmol/l, had a sensitivity of 100% and a specificity of 90% to discriminate between AVP deficiency and primary polydipsia (11). The gene discussed is AVP; the disease is neurohypophyseal diabetes insipidus.