Serum or Plasma Free Light Chain Immunoassay (kappa and lambda)
This test measures the free kappa and lambda light chains in your blood, which are small protein fragments produced by white blood cells. It helps diagnose conditions like multiple myeloma, lymphoma, or other blood disorders.
["Light chains can indicate abnormal immune system activity or cancer."]
Key facts at a glance
- LOINC
- 18044-8
- Short code
- LV EF US.2D+SP-EL
- Synonyms
- LV EF US.2D+SP-EL
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-d-calculated-by-single-plane-ellipse-method
- 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, weight loss, frequent infections, or swollen lymph nodes. It’s also used to monitor conditions like multiple myeloma, where abnormal plasma cells produce too many light chains.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into a vein (usually in your arm) to draw blood. If you’re on blood thinners, let your provider know before the test.
What the Results Mean
High levels of free light chains can signal multiple myeloma or other blood cancers. Low or normal levels don’t necessarily mean you’re healthy, but they may help rule out certain disorders. Results are interpreted by your doctor in the context of your symptoms and medical history.
Common Conditions This Test Helps Diagnose
This test is often used to diagnose or monitor multiple myeloma, lymphoma, or other plasma cell dyscrasias (abnormalities in blood cells). It can also help detect conditions like monoclonal gammopathy of undetermined significance (MGUS), a precursor to myeloma.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Light chains are fragments of heavy chains produced by plasma cells. When these cells become cancerous (e.g., in multiple myeloma), they release excessive free light chains into the blood. Elevated levels can indicate cancer progression, while monitoring helps track treatment effectiveness.
Short name
Free Light Chain Test
Frequently asked questions
What does an abnormal result mean?
Can diet or medications affect this test?
How often is this test repeated?
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