Immunoglobulin Light Chain Protein in Serum (Free Light Chains)
This test measures the levels of free light chains (the smaller protein parts of antibodies) in your blood, which can help identify certain immune system conditions or cancers.
["Free light chains may indicate hidden immune disorders or cancers like multiple myeloma."]
Key facts at a glance
- LOINC
- 44793-8
- Short code
- Immunoglobulin LC Pnl Ser-mCnc
- Synonyms
- Immunoglobulin LC Pnl Ser-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like unexplained fatigue, frequent infections, or unexplained weight loss. It’s also used when blood tests for complete blood counts (CBCs) or other markers suggest an underlying immune or blood disorder. Sometimes, it’s part of a broader evaluation for conditions like multiple myeloma, lymphoma, or other hematologic malignancies.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours if your blood is drawn early in the morning. Wear a loose shirt for easy access. Bring any medications or supplements you’re taking, as some may affect results.
How the Test Is Performed
A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief sting, but it usually doesn’t cause significant discomfort. The blood is then sent to a lab for analysis.
What the Results Mean
Results are typically reported as separate levels for kappa and lambda light chains. Elevated levels of one type (or an imbalance between them) can signal conditions like multiple myeloma, lymphoma, or other immune disorders. Your doctor will interpret the results in the context of your symptoms and overall health.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free light chains are normally balanced in the blood, but imbalances or elevated levels can indicate hidden cancers (such as multiple myeloma) or immune system dysfunctions. This test helps doctors diagnose conditions that might not show up on standard blood tests alone. It’s also useful for monitoring treatment progress in certain cancers.
Short name
Free Light Chains
Frequently asked questions
What causes abnormal free light chain levels?
How are free light chain results used in treatment?
Can diet or lifestyle affect free light chain test results?
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 16, 2026. · Read our editorial policy