[Hormones as biomarkers for diagnosis and prognosis].

Procalcitonin is a biomarker for estimating the likelihood of a bacterial infection. Procalcitonin-guided antibiotic therapy can reduce antibiotic overuse in respiratory tract infections. The differential diagnosis of water-electrolyte imbalances is challenging. Copeptin is co-secreted with arginine vasopressin (AVP) and is a reliable surrogate of plasma AVP. Copeptin may become a useful diagnostic tool in patients with polydipsia-polyuria syndrome and hyponatremia. Copeptin is also known to mirror different levels of stress. It appears to have an interesting potential as a new prognostic biomarker in patients with ischemic stroke. Biomarkers should not be used without the clinical context. They are meant to complement clinical judgment based upon a synthesis of available clinical and laboratory features in each patients.