Serum or Plasma Free Light Chain Immunoglobulin (Free Kappa and Lambda Light Chains)
This test measures the free light chains (kappa and lambda) produced by plasma cells, which are part of the immune system. These chains can be elevated in conditions affecting the bone marrow or immune system.
["Elevated free light chains may signal underlying health concerns like multiple myeloma or other blood disorders."]
Key facts at a glance
- LOINC
- 4536-9
- Short code
- DO-Hgb MFr Bld
- Synonyms
- DO-Hgb MFr Bld
- Category
- hematology
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 12
- Ref high
- 17.5
- Critical range
- 7 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85018
- SNOMED
- 900000000000003004
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test to investigate symptoms such as fatigue, unexplained weight loss, bone pain, or recurrent infections. It can also help diagnose or monitor conditions like multiple myeloma, lymphoma, or other blood disorders that affect plasma cells.
What to Expect Before the Test
No special preparation is needed. You may have a blood draw, where a small amount of blood is taken from a vein in your arm. If you’re on blood thinners, let your provider know before the test.
What the Test Measures
The test measures two types of free light chains: kappa and lambda. These are small protein fragments released by plasma cells. Abnormal levels may indicate conditions like plasma cell disorders or certain cancers.
Possible Results and Their Meaning
Results are often reported as separate values for kappa and lambda light chains. Elevated levels of one type (usually kappa) or an imbalance between them may signal a problem with plasma cells. Your provider will interpret the results in the context of your symptoms and medical history.
Reference range
Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free light chains are normally present in small amounts in the blood. When plasma cells become abnormal (as in multiple myeloma or other disorders), they produce excessive free light chains. High levels can help diagnose these conditions, guide treatment decisions, or monitor disease progression. Imbalances between kappa and lambda chains may also suggest specific types of blood disorders.
Short name
Free Light Chains
Frequently asked questions
What causes elevated free light chains?
How are free light chains monitored?
Can free light chains be affected by diet or medications?
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