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Serum or Plasma Free Light Chain Immunoassay (Quantitative)

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

This test measures the free light chains (kappa and lambda) produced by plasma cells, often used to evaluate conditions like multiple myeloma or other monoclonal gammopathies.

Quick summary

["Assessing abnormal protein production in your blood for potential blood disorders."]

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

Key facts at a glance

LOINC
104151-6
Short code
LV EF US.2D.A4C+biplane
Synonyms
LV EF US.2D.A4C+biplane
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-d-a-c-calculed-by-biplane-method
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

Doctors may order this test if you have symptoms like unexplained fatigue, frequent infections, or unexplained bone pain. It can also be used to monitor treatment progress in certain blood cancers or immune disorders.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, typically drawn from your arm. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

High levels of free light chains may indicate conditions such as multiple myeloma, lymphoma, or other plasma cell disorders. Low or normal levels usually don’t signal an issue unless part of a broader diagnostic evaluation.

Common Conditions Monitored

This test helps diagnose and monitor conditions like multiple myeloma, Waldenström macroglobulinemia, and other monoclonal gammopathies. It may also be used in patients with chronic kidney disease or autoimmune disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free Light Chains (Serum/Plasma)

Frequently asked questions

What causes abnormal free light chain levels?
Abnormal levels can result from diseases affecting plasma cells, such as multiple myeloma, where too many abnormal light chains are produced. Other conditions like kidney disease or certain infections may also affect light chain levels.
How often should this test be repeated?
Your doctor will determine the frequency based on your diagnosis and treatment plan. Regular monitoring may be needed if you have a known condition affecting light chains, such as multiple myeloma.
Can diet or lifestyle affect this test results?
Diet or lifestyle factors typically do not directly influence free light chain levels, but maintaining overall health and following your doctor’s advice for managing any underlying conditions is important.
  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