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Cerebrospinal Fluid Immunoglobulin Free Light Chains (Ig Free Light Chains)

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

This test measures free light chains—small protein fragments produced by antibodies in your cerebrospinal fluid (CSF). It helps detect abnormal antibody production, often linked to conditions like multiple myeloma or other lymphoproliferative disorders.

Quick summary

["This test helps diagnose or monitor conditions affecting antibody production in the brain’s fluid."]

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

Key facts at a glance

LOINC
13917-0
Short code
C immitis Ab Titr CSF CF
Synonyms
C immitis Ab Titr CSF CF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
comp-fix
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms like headaches, neurological issues, or a suspected blood-related disorder. It’s also used when investigating conditions affecting the immune system or central nervous system.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your back to collect CSF through a lumbar puncture (spinal tap). The procedure takes about 15–30 minutes, and you may feel mild discomfort.

What the Test Results Mean

Abnormal levels of free light chains in CSF can indicate conditions like multiple myeloma, lymphoma, or other immune system disorders. Your doctor will compare results with your symptoms and other tests for a full evaluation.

Common Conditions Monitored

This test is often used to diagnose or track conditions such as plasma cell dyscrasias (e.g., multiple myeloma), primary central nervous system lymphoma, or other immune-mediated diseases affecting CSF.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CSF Free Light Chains

Frequently asked questions

What does a positive or abnormal result mean?
An abnormal result may signal an underlying immune disorder, such as multiple myeloma or lymphoma, requiring further evaluation with additional tests or biopsies.
How often should I get this test?
Frequency depends on your symptoms and diagnosis. Your doctor will determine if repeat testing is needed for monitoring or follow-up.
Does this test involve radiation?
No, this test does not involve radiation. The procedure uses a needle to collect CSF, which is then analyzed in a lab.
  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