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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 (a part of antibodies) in your blood. It helps diagnose conditions like multiple myeloma, lymphoma, or other blood disorders.

Quick summary

["Free light chains can signal hidden blood cancers or immune system issues."]

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

Key facts at a glance

LOINC
5867-7
Short code
FLUBV Ag Spec Ql IF
Synonyms
FLUBV Ag Spec Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 order this test if you have symptoms like unexplained fatigue, frequent infections, bone pain, or if tests for other blood disorders (like multiple myeloma) have shown abnormal results. It may also be used to monitor treatment progress or check for hidden cancer spread.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood. If you’re on certain medications, let your provider know. Avoid heavy exercise or stress before the draw.

What Happens During the Test

A healthcare professional will insert a small needle into a vein in your arm to collect a blood sample. You may feel a slight pinch, but it’s usually over quickly. The blood is then sent to a lab for analysis using an immunoassay method to detect free kappa light chains.

What the Results Mean

Results are compared to a reference range for healthy adults. Elevated levels may indicate conditions like multiple myeloma, lymphoma, or other monoclonal gammopathies. Very low levels might suggest immune system dysfunction or certain genetic disorders. Your provider will discuss the results with you in detail.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal free light chain levels can signal underlying blood cancers (e.g., multiple myeloma) or immune system disorders. High levels may reflect an overproduction of antibodies, while low levels could hint at immune deficiencies or other metabolic issues. Regular monitoring is key for patients with known blood disorders.

Short name

Free Kappa Light Chain

Frequently asked questions

What causes free kappa light chains to be elevated?
Elevated free kappa light chains are most commonly linked to multiple myeloma, lymphoma, or other plasma cell dyscrasias. They can also appear in conditions like chronic infections, autoimmune diseases, or certain genetic disorders. If you’ve had recent cancer treatment or have symptoms like bone pain or fatigue, this test may be part of your evaluation.
What if my results are abnormal?
If your results are abnormal, your healthcare provider will review them with you and may order additional tests (like bone marrow biopsy or imaging) to investigate further. They’ll also consider your symptoms, medical history, and other test results to determine the next steps, which could include treatment adjustments or closer monitoring.
Can I avoid this test if I don’t have symptoms?
Not always. Some patients get this test as a routine check or during follow-up for conditions like kidney disease, autoimmune disorders, or cancer risk. If your provider recommends it, it’s important to proceed—even if you feel well—to catch potential issues early.
  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