Endocrine Abstracts

Introduction: Measurement of copeptin is proposed for use in the differential diagnosis of polyuric syndrome.

Aims: To evaluate the diagnostic value of copeptin levels in patients with polyuria syndrome.

Materials and methods: The study included 17 patients with central diabetes insipidus (CDI), 3 patients with nephrogenic diabetes insipidus (NDI), 7 patients with primary polydipsia (PP) and 26 control subjects. In all individuals blood samples were taken after 8 h fast. Copeptin levels were measured by BRAHMS CT-proAVP Kryptor.

Results: In 38% (10) of healthy volunteers, the level of copeptin was less than 5 pmol/l. The rest control individuals average levels were 8.5±2.8 pmol/l (from 5.41 to 15.16). Patients with CDI in 82% had copeptin levels below 5 pmol/l, the rest 6.8±0.8. Patients with PP in 71% had copeptin levels below 5 pmol/l, two patients had levels 5.3 and the 6.7 pmol/l. All NDI patients had measurable copeptin concentrations in the blood – 8.6, 12.9 and 14.5 pmol/l.

Conclusions: A large proportion of values in the range below the sensitivity of the method of determination in healthy people and patients with PP makes it difficult to differentiate them from ones with CDI. The increase in method sensitivity would be desirable.