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Orexin A in Cerebrospinal Fluid (CSF)

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of orexin A, a neuropeptide involved in regulating sleep-wake cycles, in your cerebrospinal fluid. It may be used to evaluate conditions affecting brain signaling related to sleep disorders.

Quick summary

["Orexin A in CSF helps assess sleep regulation pathways in the brain."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
91670-0
Short code
Orexin-A CSF-mCnc
Synonyms
Orexin-A CSF-mCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like insomnia, excessive daytime sleepiness, or other sleep disturbances that suggest a neurological issue affecting orexin signaling. It could also be part of a broader evaluation for conditions such as narcolepsy or other sleep disorders linked to brain chemistry imbalances.

What to Expect Before the Test

No special preparation is typically needed. You may be asked to fast for a short period before the procedure, but this depends on your specific care plan. Your provider will explain any instructions to follow.

How the Test Is Performed

A healthcare professional will perform a lumbar puncture (spinal tap) to collect a sample of cerebrospinal fluid. This involves inserting a needle into your lower back to draw fluid from the spinal canal. The procedure is usually done in a hospital or clinic setting.

What the Results Mean

Results are interpreted by your healthcare provider based on your symptoms, medical history, and other test findings. Abnormal levels may indicate underlying sleep disorders or neurological conditions affecting orexin function.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CSF Orexin A

Frequently asked questions

What causes orexin A levels in CSF to be tested?
Testing may be recommended if you have symptoms like sudden sleep attacks, extreme fatigue, or irregular sleep patterns that doctors suspect could be linked to orexin dysfunction. It’s also sometimes used in research or specialized evaluations for unexplained sleep disturbances.
What are the possible risks or side effects of this test?
The most common risk is mild pain or discomfort at the injection site. Rarely, there may be temporary headaches, bruising, or infection. Your provider will discuss risks with you before the procedure.
How long does it take to get results from this test?
Results are typically available within a few days to a week, depending on lab processing times. Your healthcare provider will contact you once they have the findings and discuss next steps.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy