Anti-CASPR1 Antibody (Serum)
This test measures the presence of antibodies against the CASPR1 protein, which is linked to certain types of autoimmune neurological conditions. These antibodies may help diagnose conditions like paraneoplastic neurological syndromes or certain forms of limbic encephalitis.
["This test may help identify rare neurological disorders caused by immune system attacks on brain and nerve proteins."]
Key facts at a glance
- LOINC
- 106785-9
- Short code
- CASPR1 AB
- Synonyms
- CASPR1 Ab Ser Ql CBA IFA
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) - red-top or gold-top tube preferred; alternatively, red-top plain tube with serum separated after clotting.
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- cba-ifa
- CPT
- 86255
- SNOMED
- 115341000221108
- Specimen volume
- 1-2 mL of serum (minimum 0.5 mL).
- Stability
- Stable at room temperature for up to 8 hours; refrigerated at 2-8°C for up to 7 days; frozen at -20°C or below for up to 6 months for long-term storage. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 200
- Lipemia max
- 100
- Icterus max
- 40
- TAT
- 72–168 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms such as unexplained memory problems, seizures, movement disorders, or other neurological symptoms that don’t have a clear cause. It could also be used in cases where other tests for autoimmune conditions have been negative. This test is sometimes done alongside other antibody tests to help narrow down possible diagnoses.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re nervous about needles, let your healthcare provider know so they can offer comfort measures.
What Happens During the Test
A healthcare professional will take a small amount of blood from a vein in your arm. The blood will be sent to a lab for testing. The results are typically available within a few days, depending on lab processing times.
What the Results Mean
If your test results show a positive presence of anti-CASPR1 antibodies, it may indicate an autoimmune response affecting your nervous system. However, this doesn’t confirm a specific diagnosis on its own. Your healthcare provider will consider your symptoms, medical history, and other test results to determine the next steps.
Reference range
Negative: No specific antibodies to Contactin-associated protein 1 (CASPR1) detected. Positive: Antibodies to Contactin-associated protein 1 (CASPR1) detected. Results should be interpreted in conjunction with clinical findings, nerve conduction studies, and other paraneoplastic/autoimmune antibody panels.N/A
No fasting required. No special patient preparation needed. Patient should be informed that this test detects antibodies associated with autoimmune peripheral nerve disorders and that results are interpreted alongside clinical evaluation and other diagnostic tests.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive anti-CASPR1 antibodies are associated with certain neurological disorders, such as limbic encephalitis or paraneoplastic neurological syndromes, which can occur in both cancer patients and those without cancer. These conditions can cause symptoms like memory loss, seizures, or movement problems. While the antibodies themselves don’t always lead to symptoms, they can guide further testing and treatment planning.
Short name
Anti-CASPR1 IgG
Frequently asked questions
How long does it take to get results from this test?
Can this test be done at home?
Are there any risks or side effects from this blood test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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 15, 2026. · Read our editorial policy