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Serum or Plasma Free Light Chain Kappa (Immunoassay)

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

This test measures the amount of free kappa light chains in your blood, which are small protein fragments produced by plasma cells. These fragments can be elevated in conditions affecting plasma cells, such as multiple myeloma or other monoclonal gammopathies.

Quick summary

["Elevated levels may signal an underlying blood disorder needing further medical evaluation."]

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

Key facts at a glance

LOINC
3222-7
Short code
Fact X+AAC Ag PPP IA-aCnc
Synonyms
Fact X+AAC Ag PPP IA-aCnc
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

What Is Free Kappa Light Chain Testing Used For?

Free kappa light chains are part of the immunoglobulin (antibody) production process. When plasma cells become abnormal (e.g., in multiple myeloma or other cancers), they may produce excessive free light chains instead of complete antibodies. This test helps doctors monitor these conditions by detecting abnormal levels in your blood.

Why Might Your Doctor Order This Test?

Your doctor may order this test if you have symptoms like unexplained fatigue, bone pain, frequent infections, or if they suspect a plasma cell disorder. It’s also used to monitor treatment progress in patients already diagnosed with conditions like multiple myeloma.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The sample is sent to a lab where it’s analyzed using an immunoassay method to measure free kappa light chains. No special preparation is needed, but fasting may be advised depending on your doctor’s instructions.

What Do Results Mean?

Results are compared to a reference range specific to your lab. Elevated levels may indicate an overproduction of free light chains, which can signal conditions like multiple myeloma or other plasma cell disorders. Low levels alone are usually not clinically significant unless part of a broader evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Elevated Free Kappa Light Chains

Short name

Free Kappa Light Chain

Frequently asked questions

What could cause elevated levels of free kappa light chains?
Elevated free kappa light chains are most commonly associated with multiple myeloma, a cancer of plasma cells. They can also appear in other plasma cell dyscrasias (e.g., monoclonal gammopathy of undetermined significance), lymphoproliferative disorders, or certain infections. Rarely, they may be elevated in healthy individuals due to normal fluctuations, but further testing is needed to investigate.
How often should I get this test?
Your doctor will determine the frequency based on your medical history, symptoms, and diagnosis. If you have a known plasma cell disorder, this test may be part of regular monitoring to track disease progression or response to treatment. Follow your doctor’s guidance for timing and frequency.
Can lifestyle changes affect this test result?
While diet or exercise may influence overall health, they typically do not directly affect free light chain measurements. However, certain medications (e.g., chemotherapy, steroids) or conditions (e.g., kidney disease) can impact lab results. Always discuss any medications or health changes with your doctor before testing.
  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