Copeptin as a Predictor of Seizure Diagnosis and Seizure Type in Emergency Department Patients

Objective To evaluate the diagnostic utility of serum copeptin (CPT) levels in distinguishing true seizures from Pseudo or functional/dissociative seizures (FDS) in adult patients presenting to the emergency department, and to investigate possible differences in CPT levels among various seizure types. Methods This prospective, observational study was conducted at a tertiary research hospital between September 2023 and September 2024. Adult patients presenting to the emergency department with seizure complaints were screened and, after applying exclusion criteria, 59 patients were included. Patients were classified based on clinical, laboratory, and EEG findings into seizure or FDS groups. Serum CPT and interleukin-6 (IL-6) levels were measured using ELISA. Results Of the 59 patients, 24 were diagnosed with true seizures and 35 with FDS. No significant difference was found in serum CPT levels between the seizure and FDS groups (p = 0.755). However, absence seizures were associated with notably higher CPT concentrations compared to other seizure types. Glucose, base deficit, CRP (C-reactive protein), and IL-6 levels were significantly elevated in the seizure group relative to FDS. Serum CPT values were not predictive of clinical outcomes or the need for intensive care admission. Conclusion Serum CPT levels are not useful for differentiating between true seizures and FDS in adult emergency patients. Nevertheless, elevated CPT may have a role in the identification of absence seizures. Further multicenter studies with larger cohorts and standardized sampling times are warranted to clarify the diagnostic and prognostic value of CPT in seizure disorders.