Plasma Free Light Chain Immunoassay (kappa and lambda)
This test measures the free kappa and lambda light chains in your plasma, which are small protein fragments produced by your immune system. These fragments can help diagnose conditions affecting your immune system, such as multiple myeloma or other plasma cell disorders.
["This test helps identify abnormal immune cell activity that may require further medical evaluation."]
Key facts at a glance
- LOINC
- 75977-9
- Short code
- Fet Chr X + Y aneup Plas.cfDNA Ql
- Synonyms
- Fet Chr X + Y aneup Plas.cfDNA Ql
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- dosage-of-chromosome-specific-cf-dna
- 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 Is This Test Done?
Your healthcare provider may order this test if you have symptoms like unexplained fatigue, frequent infections, bone pain, or changes in kidney function. It may also be used to monitor conditions like multiple myeloma, lymphoma, or other blood disorders that affect light chains.
What Does the Test Involve?
A blood sample is taken from a vein, usually in your arm. The blood is processed to separate plasma, which is then tested for free light chains using a specialized immunoassay method.
What Are the Results Typically Used For?
Results help determine if your immune system is producing abnormal levels of light chains, which can indicate underlying conditions. Elevated levels may suggest conditions like multiple myeloma, where plasma cells produce too many light chains.
What Are Common Conditions Monitored With This Test?
This test is often used to diagnose or monitor conditions such as multiple myeloma, Waldenström macroglobulinemia, and other plasma cell dyscrasias. It may also be part of routine monitoring for patients with known immune system disorders.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormally high levels of free kappa or lambda light chains can signal conditions affecting plasma cells, such as multiple myeloma. These levels can help guide treatment decisions, track disease progression, or assess response to therapy. Low levels may be less clinically significant but should be evaluated in the context of your overall health and symptoms.
Short name
Free Light Chain Test
Frequently asked questions
What does an abnormal result mean?
The frequency of testing depends on your medical condition and treatment plan. If you have a known disorder like multiple myeloma, your doctor may recommend regular monitoring. If this test is part of a routine check, follow your provider’s instructions for timing and frequency.
What should I do if I have symptoms before my 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