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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 or the bone marrow.

Quick summary

["Elevated levels may signal underlying diseases like multiple myeloma or other plasma cell disorders."]

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

Key facts at a glance

LOINC
44568-4
Short code
FLUBV Ab Ser Ql CF
Synonyms
FLUBV Ab Ser Ql CF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
comp-fix
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 Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like unexplained fatigue, frequent infections, or bone pain. It’s also used to monitor conditions like multiple myeloma, lymphoma, or other blood disorders that affect plasma cells.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results are typically compared to a standard range for healthy adults. High levels may indicate plasma cell disorders, while low levels could be normal or related to certain medications or conditions affecting protein production.

Common Conditions Monitored

This test helps diagnose or track conditions like multiple myeloma, Waldenström macroglobulinemia, or other monoclonal gammopathies, where abnormal amounts of light chains are produced.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated free kappa light chains can signal abnormal plasma cell activity, often linked to cancers like multiple myeloma or monoclonal gammopathies. Low levels may occur in conditions affecting protein synthesis or in patients on certain medications.

Short name

Free Kappa Light Chain

Frequently asked questions

What causes free kappa light chains to be elevated?
Elevated levels are most commonly associated with plasma cell disorders, such as multiple myeloma or other monoclonal gammopathies. Rarely, they can be elevated in infections, autoimmune diseases, or certain medications.
How often should I get this test?
Your healthcare provider will determine the frequency based on your medical history, symptoms, and treatment plan. Regular monitoring may be needed if you have a diagnosed plasma cell disorder.
Can diet or lifestyle affect this test result?
Diet or lifestyle changes typically do not affect free light chain levels. However, if you’re on medications that impact protein metabolism, discuss them with your provider 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