Skip Ribbon Commands
Skip to main content
Sign In

26271 Orexin-A/Hypocretin-1, Spinal Fluid (ORXNA)

Orexin-A/Hypocretin-1, Spinal Fluid (ORXNA)
Test Code: ORXNASO
Synonyms/Keywords

​Hypocretin
Orexin
Hypocretin-1
Orexin-A

Useful For

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.

Specimen Requirements
Specimen TypePreferred Container/TubeAcceptable Container/TubeSpecimen VolumeSpecimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​CSF​Sterile Vial​1.5 mL​0.5 mL
Collection Processing Instructions

Patient Preparation: Patient should not have recently received radioisotopes, either therapeutically or diagnostically, due to potential assay interference.

Collection Instructions:

1. Obtain aliquot from second collection vial (preferred, not required).

2. Hemolyzed specimens will give false-positive results. Specimens should be centrifuged to remove any red cells prior to shipping.

Specimen Stability Information
Specimen TypeTemperatureTime
​CSF​Frozen​120 days
Rejection Criteria
Gross HemolysisReject
Interference

Several factors contribute in the decision to measure orexin in cerebrospinal fluid (CSF). Orexin deficiency in HLA DQB1*0602-negative patients is rare. This test may be considered for the diagnosis of narcolepsy type 1, after HLA positivity is shown, if a clinical multiple sleep latency test is negative and/or unavailable due to potential confounding circumstances. It may also be considered if there is suspicion that cataplexy is of psychogenic origin.

Orexin (hypocretin-1) concentrations between 111 to 200 pg/mL are considered intermediate and have limited diagnostic utility for type 1 narcolepsy, as they may be representative of other neurological disorders.

This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. A recommended time period before collection cannot be made because it will depend on the isotope administered, the dose given, and the clearance rate in the individual patient.

Some patients who have been exposed to animal antigens, either in the environment or as part of treatment or imaging procedures, may have circulating anti-animal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results. 

Performing Laboratory Information
Performing LocationDay(s) Test PerformedAnalytical TimeMethodology/Instrumentation
​Mayo Clinic Laboratories​Third Tuesday of every month​3 days​Radioimmunoassay (RIA)
Reference Lab
Test Information

​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.

Reference Range Information
Performing LocationReference Range
​Mayo Clinic Laboratories

Normal individuals should be >200 pg/mL

Previous literature has defined CSF orexin-A/hypocretin-1 concentrations of < or = 110 pg/mL as being consistent with narcolepsy type 1 - (Mignot E: Arch Neurol 2002:59;1553-1562). Concentrations between 111 to 200 pg/mL are considered intermediate and have limited diagnostic utility for narcolepsy, as they may be representative of other neurological disorders. Concentrations of >200 pg/mL are considered normal. 

Interpretation

​The diagnostic criteria for type 1 narcolepsy in the International Classification of Sleep Disorders (3) include the presence of hypersomnia, cataplexy (episodes of muscle weakness in response to emotional stimuli) and/or measured cerebrospinal fluid (CSF) orexin (hypocretin-1) concentrations less than or equal to 110 pg/mL.

Orexin (hypocretin-1) CSF concentrations have been classified into 3 categories in the literature. They include low (< or =110 pg/mL), which is indicative of type 1 narcolepsy; intermediate (ranges between 111-200 pg/mL); and normal (>200 pg/mL). Previous studies have shown that 106 of 113 patients with clinically defined type 1 narcolepsy exhibited low (<110 pg/mL) orexin concentrations. In another study, all 48 healthy individuals exhibited orexin (hypocretin-1) CSF concentrations above 200 pg/mL.

In the periodic hypersomnia disorder of Kleine-Levin syndrome, the CSF orexin levels may be low during the sleepy periods, with return to normal when individuals are not sleepy. 

Outreach CPTs
CPTModifier
(if needed)
QuantityDescriptionComments
​83519​1
Synonyms/Keywords

​Hypocretin
Orexin
Hypocretin-1
Orexin-A

Ordering Applications
Ordering ApplicationDescription
​COM​Orexin-A/Hypocret-1, Spinal F
​Cerner​Orexin/Hypocret, SF (ORXNA)
​Centricity​Orexin/Hypocret, SF (ORXNA)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen TypePreferred Container/TubeAcceptable Container/TubeSpecimen VolumeSpecimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​CSF​Sterile Vial​1.5 mL​0.5 mL
Collection Processing

Patient Preparation: Patient should not have recently received radioisotopes, either therapeutically or diagnostically, due to potential assay interference.

Collection Instructions:

1. Obtain aliquot from second collection vial (preferred, not required).

2. Hemolyzed specimens will give false-positive results. Specimens should be centrifuged to remove any red cells prior to shipping.

Specimen Stability Information
Specimen TypeTemperatureTime
​CSF​Frozen​120 days
Rejection Criteria
Gross HemolysisReject
Interference

Several factors contribute in the decision to measure orexin in cerebrospinal fluid (CSF). Orexin deficiency in HLA DQB1*0602-negative patients is rare. This test may be considered for the diagnosis of narcolepsy type 1, after HLA positivity is shown, if a clinical multiple sleep latency test is negative and/or unavailable due to potential confounding circumstances. It may also be considered if there is suspicion that cataplexy is of psychogenic origin.

Orexin (hypocretin-1) concentrations between 111 to 200 pg/mL are considered intermediate and have limited diagnostic utility for type 1 narcolepsy, as they may be representative of other neurological disorders.

This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. A recommended time period before collection cannot be made because it will depend on the isotope administered, the dose given, and the clearance rate in the individual patient.

Some patients who have been exposed to animal antigens, either in the environment or as part of treatment or imaging procedures, may have circulating anti-animal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results. 

Useful For

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.

Reference Range Information
Performing LocationReference Range
​Mayo Clinic Laboratories

Normal individuals should be >200 pg/mL

Previous literature has defined CSF orexin-A/hypocretin-1 concentrations of < or = 110 pg/mL as being consistent with narcolepsy type 1 - (Mignot E: Arch Neurol 2002:59;1553-1562). Concentrations between 111 to 200 pg/mL are considered intermediate and have limited diagnostic utility for narcolepsy, as they may be representative of other neurological disorders. Concentrations of >200 pg/mL are considered normal. 

Interpretation

​The diagnostic criteria for type 1 narcolepsy in the International Classification of Sleep Disorders (3) include the presence of hypersomnia, cataplexy (episodes of muscle weakness in response to emotional stimuli) and/or measured cerebrospinal fluid (CSF) orexin (hypocretin-1) concentrations less than or equal to 110 pg/mL.

Orexin (hypocretin-1) CSF concentrations have been classified into 3 categories in the literature. They include low (< or =110 pg/mL), which is indicative of type 1 narcolepsy; intermediate (ranges between 111-200 pg/mL); and normal (>200 pg/mL). Previous studies have shown that 106 of 113 patients with clinically defined type 1 narcolepsy exhibited low (<110 pg/mL) orexin concentrations. In another study, all 48 healthy individuals exhibited orexin (hypocretin-1) CSF concentrations above 200 pg/mL.

In the periodic hypersomnia disorder of Kleine-Levin syndrome, the CSF orexin levels may be low during the sleepy periods, with return to normal when individuals are not sleepy. 

For more information visit:
Performing Laboratory Information
Performing LocationDay(s) Test PerformedAnalytical TimeMethodology/Instrumentation
​Mayo Clinic Laboratories​Third Tuesday of every month​3 days​Radioimmunoassay (RIA)
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPTModifier
(if needed)
QuantityDescriptionComments
​83519​1
For most current information refer to the Marshfield Laboratory online reference manual.