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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 your immune system. These fragments can be elevated in certain blood disorders.

Quick summary

["Elevated levels may signal conditions 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
44573-4
Short code
FLUBV Ag Nose Ql IF
Synonyms
FLUBV Ag Nose 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 Is Done

Your healthcare provider may order this test if you have symptoms like unexplained fatigue, frequent infections, or unexplained bone pain. It may also be 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 blood draw from a vein in your arm, similar to other blood tests. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results are compared to a general reference range for healthy adults. High levels may indicate plasma cell disorders, while low levels could suggest other immune-related conditions. Your provider will interpret results in the context of your overall health.

Common Conditions Linked to Abnormal Results

Elevated free kappa light chains are often linked to multiple myeloma, a cancer of plasma cells, or other plasma cell dyscrasias. They can also appear in conditions like monoclonal gammopathy of undetermined significance (MGUS).

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

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 plasma cell disorders, such as multiple myeloma or other plasma cell diseases. They can also be found in conditions like MGUS or certain infections.
How often should this test be repeated?
Frequency depends on your diagnosis and treatment plan. If you have a known plasma cell disorder, your provider may recommend regular monitoring. Follow-up schedules are tailored to your specific situation.
Can diet or lifestyle affect this test result?
Diet or lifestyle factors generally do not directly affect free light chain measurements. However, if you’re on medications that impact blood or immune function, inform 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