Copeptin proAVP (s) (Serum (s), frozen)

For the medical clarification of polyuria/polydipsia syndrome.
No coffee, tea or nicotine before blood collection. Stop medication 48 hours prior, if necessary.
The determination of copeptin has the advantage over ADH that serum can be used instead of EDTA plasma.
Parallel determination of osmolality in serum is recommended.

• Polyuria-polydipsia syndrome: improved differential diagnosis
• Monitoring for vasopressin deficiency after pituitary surgery
• Reliable follow-up for Hypopituitarism after traumatic brain injury

In the differential more…

if copeptin proAVP < 21.4 pmol/l, an infusion with 3% NaCl solution should be given until serum sodium has risen > 147 mmol/l. This is followed by another blood draw for determination of stimulated copeptin. The determination of copeptin under 3% NaCl stimulation without prior fluid restriction is clearly superior to the indirect thirst test in the differentiation of patients with primary polydipsia and central diabetes insipidus. A major diagnostic advance is the markedly improved differentiation of patients with primary polydipsia from those with only partial hormone deficiency. (Fenske et al. NEJM 2018; 379: 428-439)