Serum Free Kappa Light Chain (Free Lambda Light Chain)
This blood test measures the free kappa and lambda light chains, small protein fragments produced by plasma cells. These fragments can be elevated in conditions affecting the immune system or bone marrow.
["Free light chains help diagnose and monitor certain blood disorders."]
Key facts at a glance
- LOINC
- 48378-4
- Short code
- Kappa LC Free/Lambda Free Ser
- Synonyms
- Kappa LC Free/Lambda Free Ser
- 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 to check for multiple myeloma, a cancer of plasma cells, or other conditions like monoclonal gammopathy of undetermined significance (MGUS). It can also help evaluate symptoms like kidney problems, anemia, or unexplained fatigue that might be linked to abnormal protein production.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. The process takes about 5 minutes. If you have a hard time with needles, let your doctor or nurse know in advance.
What the Results Mean
Results show the levels of free kappa and lambda light chains separately. Elevated levels of one type (usually kappa) may indicate multiple myeloma or other plasma cell disorders. Your doctor will compare these results with your overall health and other tests to interpret them.
Possible Conditions Linked to Abnormal Results
High levels of free light chains can be seen in multiple myeloma, lymphoma, or other plasma cell disorders. They may also appear in conditions like kidney disease or certain infections. Low levels are less common but could be seen in rare genetic disorders.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is critical for diagnosing and monitoring plasma cell disorders. The free light chain test helps detect abnormalities that standard protein electrophoresis might miss, especially in early stages of multiple myeloma. It’s often used alongside other tests like urine protein screening or bone marrow biopsy to guide treatment decisions.
Short name
Free light chain test
Frequently asked questions
What does an elevated free light chain mean?
Can this test detect early multiple myeloma?
Does this test require fasting?
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