Serum/Plasma Free Light Chain Kappa to Lambda Ratio (Free Light Chain Ratio)
This test measures the balance between two types of light chains (kappa and lambda) found in your blood, which can help detect multiple myeloma or other conditions affecting plasma cells.
["This test helps diagnose or monitor conditions linked to abnormal light chain production."]
Key facts at a glance
- LOINC
- 74422-7
- Short code
- MuV IgG Fld Ql IA
- Synonyms
- MuV IgG Fld Ql IA
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- CPT
- 82784
- 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 if you have symptoms like unexplained fatigue, frequent infections, bone pain, or kidney problems. It’s also used to check for multiple myeloma, a cancer of plasma cells, or other conditions like monoclonal gammopathy of undetermined significance (MGUS).
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. If you’re on blood thinners, let your provider know to avoid unnecessary bleeding.
How the Test Works
Blood is drawn and separated into components. The kappa and lambda light chains are measured separately using immunoassay techniques to determine their relative amounts.
Possible Results and Interpretation
An abnormal ratio (either too high or too low) may indicate conditions like multiple myeloma, where one type of light chain is produced in excess. Your provider will review results in the context of your symptoms and other tests.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: This test is critical for diagnosing and monitoring plasma cell disorders. An elevated ratio may signal multiple myeloma or other plasma cell dyscrasias, while a skewed ratio could prompt further investigation into underlying causes, such as chronic infections or autoimmune diseases.
Short name
Free Light Chain Ratio
Frequently asked questions
What causes an abnormal free light chain ratio?
How often is this test repeated?
Can diet or medications affect this test?
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