Free Light Chain Immunoglobulin (Serum)
This test measures the free light chains (kappa and lambda) produced by your immune system’s B cells. These fragments can help detect certain conditions affecting the blood or immune system.
["This test helps identify abnormal light chain production that may signal multiple myeloma or other blood disorders."]
Key facts at a glance
- LOINC
- 95800-9
- Short code
- Immunoglobulin LC free Pnl Ur
- Synonyms
- Immunoglobulin LC free Pnl Ur
- 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 Is Done
Your doctor may order this test if you have symptoms like unexplained fatigue, frequent infections, or kidney problems. It’s also used to monitor conditions like multiple myeloma, where abnormal plasma cells produce too many light chains.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or vein to draw blood. If you’re nervous, let your healthcare provider know—they can help make it more comfortable.
What the Results Mean
High levels of free light chains may indicate conditions like multiple myeloma, lymphoma, or kidney disease. Low levels are less common but could suggest immune system issues. Your doctor will compare your results to your medical history and other tests.
Common Conditions Monitored
This test is often used to diagnose or track multiple myeloma, a cancer of plasma cells, or to check for other blood disorders like Waldenström macroglobulinemia or certain lymphomas.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free light chains are normally balanced in the body. When they’re produced in excess (often due to plasma cell disorders), they can clog kidneys or cause other complications. Elevated levels can signal cancer or immune system dysfunction, prompting further testing or treatment adjustments.
Short name
Free Light Chain Test
Frequently asked questions
What causes abnormal free light chain levels?
How are free light chains different from total immunoglobulins?
Can diet or medications 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