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Serum Free Light Chain Immunoassay (kappa and lambda)

Published: August 9, 2026Updated: August 16, 2026

This blood test measures the levels of free kappa and lambda light chains, which are small protein fragments produced by plasma cells. These fragments can help diagnose conditions like multiple myeloma or other plasma cell disorders.

Quick summary

["Light chains help doctors assess abnormal protein production in your blood."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
10497-6
Short code
Kappa AL Ag Tiss Ql ImStn
Synonyms
Kappa AL Ag Tiss Ql ImStn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immune-stain
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, bone pain, frequent infections, or kidney problems. It’s also used to monitor conditions like multiple myeloma, lymphoma, or other blood disorders where abnormal plasma cells produce excess light chains.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm for a blood draw, similar to other routine blood tests. The process takes a few minutes, and you can resume normal activities afterward.

How the Results Are Interpreted

Results compare the levels of kappa and lambda light chains to each other and to expected ranges. High levels of one type (often kappa) may indicate a plasma cell disorder, while imbalances can signal other conditions like monoclonal gammopathy.

Common Conditions Monitored

This test is critical for diagnosing and managing multiple myeloma, Waldenström macroglobulinemia, and other plasma cell dyscrasias. It also helps track treatment effectiveness and detect disease progression.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free Light Chain Test

Frequently asked questions

What does a high or low level of free light chains mean?
High levels of kappa light chains are most commonly linked to multiple myeloma or other plasma cell disorders. Low or normal levels alone don’t indicate a problem unless paired with other symptoms or test results.
Does this test require fasting?
No fasting is required for this blood test. Your blood will be drawn at a time convenient for you, and results are typically ready within a few days.
Can I take my usual medications before the test?
Yes, you can take your usual medications as scheduled. This test only involves a blood draw and doesn’t interfere with your medications.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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