LAUSR

Narcolepsy is a neurological disorder characterized by excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations, with its pathogenesis linked to hypocretin/orexin deficiency, a key regulator of the sleep-wake cycle. This study compares the diagnostic performance of radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) in measuring cerebrospinal fluid (CSF) hypocretin levels in narcolepsy patients. Twenty-five narcolepsy patients were diagnosed based on clinical symptoms and electrophysiological tests. CSF hypocretin levels were measured using RIA and ELISA, with a hypocretin level of < 110 pg/ml considered diagnostic for narcolepsy type I according to established criteria. RIA showed a significantly lower average hypocretin level (9.77±5.65 pg/ml) compared to ELISA (134.56±57.21 pg/ml). Among the 25 patients, 17 were diagnosed with narcolepsy, all of whom had RIA measurements below 110 pg/ml, achieving 100% sensitivity. In contrast, only 4 patients had hypocretin levels < 110 pg/ml using ELISA, resulting in a sensitivity of 23.53%. RIA demonstrated higher sensitivity for detecting low hypocretin concentrations, while ELISA was more accurate for higher concentrations but less sensitive at lower levels. RIA demonstrated superior sensitivity and accuracy in detecting low cerebrospinal fluid (CSF) hypocretin levels, which makes it highly valuable for the early diagnosis and ongoing monitoring of the disease. Despite these advantages, its complexity and associated costs pose significant limitations to its widespread clinical applicability. In contrast, ELISA, while less sensitive at very low concentrations, offers greater accessibility and is more suitable for large-scale screening programs. Clinicians are advised to select the most appropriate method based on their specific diagnostic requirements. This study not only contributes to the refinement of diagnostic strategies for narcolepsy but also offers valuable insights that could be applied to broader neurological disorders.