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Anti-CASPR2 Antibodies (Serum/Plasma)

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

This test measures the presence of antibodies against the CASPR2 protein, which may be linked to certain autoimmune neurological conditions.

Quick summary

["This test helps diagnose or monitor conditions like limbic encephalitis or other autoimmune-related neurological symptoms."]

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

Key facts at a glance

LOINC
90820-2
Short code
CNTNAP2CSF
Synonyms
CASPR2 Ab CSF Ql CBA IFA
Category
chemistry
Sample
csf
Container
Sterile, screw-cap, polypropylene CSF collection tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cba-ifa
CPT
86255
SNOMED
115341000221100
Specimen volume
1-2 mL of cerebrospinal fluid
Stability
Stable for 24 hours at room temperature; 7 days at 2-8°C; 1 month at -20°C. Avoid repeated freeze-thaw cycles.
Hemolysis max
200
TAT
24–168 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms such as memory loss, confusion, seizures, or unexplained neurological issues that don’t have a clear cause. It could also be part of a broader evaluation for autoimmune disorders affecting the brain or nerves.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. If you’re taking blood thinners, let your doctor know before the test.

What the Test Results Mean

Positive results (detecting antibodies) suggest a possible autoimmune response targeting CASPR2, which may be associated with specific neurological conditions. Results alone don’t diagnose a condition but can guide further testing or treatment.

Common Conditions Linked to Positive Results

Anti-CASPR2 antibodies are often found in cases of limbic encephalitis, a rare condition causing memory and mood changes, or in other autoimmune neurological disorders like paraneoplastic syndromes (when cancer triggers autoimmune responses).

Reference range

NegativeN/A

Specimen: csf

No special preparation required. Lumbar puncture is performed under sterile conditions by a qualified healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Anti-CASPR2 IgG

Frequently asked questions

What does a positive result mean for me?
A positive result means your blood contains antibodies against CASPR2, which may indicate an autoimmune response affecting your nervous system. This doesn’t mean you have a specific condition yet, but it may prompt further testing or evaluation by a neurologist or specialist.
Will I need more tests if this result is positive?
Yes, additional tests may be needed to diagnose the underlying condition. These could include imaging studies, other antibody tests, or evaluations for conditions like cancer that might trigger autoimmune responses.
Can lifestyle changes help if I have positive antibodies?
While lifestyle changes like managing stress, maintaining a balanced diet, and avoiding smoking can support overall health, they may not directly address the autoimmune response. Work closely with your healthcare team to tailor treatment to your specific needs.
  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