Test ID: ORXNA    
Orexin-A/Hypocretin-1, Spinal Fluid

Useful For Suggests clinical disorders or settings where the test may be helpful

Aiding in the diagnosis and differentiation of type 1 narcolepsy from other causes of hypersomnolence


This assay is not intended for use as a screening test.


Orexin-A (hypocretin-1) is a neuropeptide involved in the sleep/wake cycle in humans. An abnormally low concentration of orexin-A (hypocretin-1) in cerebrospinal fluid (CSF) indicates type I narcolepsy.


The diagnostic criteria for type 1 narcolepsy in the third edition of the International Classification of Sleep Disorders (2014) include the presence of hypersomnia, cataplexy (episodes of muscle weakness in response to emotional stimuli) and/or measured CSF orexin (hypocretin-1) concentrations less than or equal to 110 pg/mL .


CSF concentrations have been found to almost always be above 200 pg/mL in healthy individuals and those with non-type 1-narcoleptic sleep disorders such as narcolepsy type 2 and idiopathic hypersomnia.

Method Name A short description of the method used to perform the test

Radioimmunoassay (RIA)

NY State Available Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name Lists a shorter or abbreviated version of the Published Name for a test

Orexin-A/Hypocretin-1, CSF

Aliases Lists additional common names for a test, as an aid in searching