Plasma or Serum Free Light Chains (κ and λ) by Immunoassay
This test measures the free light chains (κ and λ) found in your blood, which are small protein fragments produced by plasma cells. These fragments can be elevated in conditions affecting plasma cell function or multiple myeloma.
["Elevated free light chains may signal underlying blood disorders or immune system issues."]
Key facts at a glance
- LOINC
- 5972-5
- Short code
- tPA Ag 20M PPP IA-mCnc
- Synonyms
- tPA Ag 20M PPP IA-mCnc
- Category
- chemistry
- Sample
- plasma
- Container
- Lavender-top (EDTA) or Green-top (Heparin)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- 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 healthcare provider may order this test to investigate symptoms such as fatigue, unexplained weight loss, bone pain, or kidney problems. It can also help diagnose conditions like multiple myeloma, lymphoma, or other plasma cell disorders. Sometimes, it’s used to monitor treatment progress or check for recurrence of these conditions.
What to Expect Before the Test
No special preparation is needed. You may have a blood draw from a vein in your arm. If you’re on blood thinners, let your provider know before the test.
What the Results Mean
Free light chains are normally present in small amounts. Abnormal levels (either too high or too low) may indicate conditions affecting plasma cells or kidney function. Your provider will interpret results in the context of your symptoms and overall health.
Common Conditions Linked to Abnormal Results
Elevated levels of free light chains are often seen in multiple myeloma, amyloidosis, or other plasma cell dyscrasias. Low levels are less common but may occur in rare genetic disorders or severe immune deficiencies.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Free light chains are a key diagnostic and monitoring tool for plasma cell-related diseases. High levels can signal cancerous plasma cell proliferation, while monitoring trends over time helps track disease progression or response to treatment. Kidney function should also be assessed if abnormal results are found, as free light chains can affect kidney health.
Short name
Free Light Chains
Frequently asked questions
What causes free light chains to be elevated?
How often should I get this test if I have a condition like multiple myeloma?
Can diet or lifestyle changes 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