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Serum or Plasma Free Light Chain Immunoassay (Quantitative)

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

This test measures the levels of free light chains, which are small protein fragments produced when antibodies break down. It helps assess conditions affecting the bone marrow or immune system.

Quick summary

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

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

Key facts at a glance

LOINC
47051-8
Short code
T palldm IgG CSF IF-aCnc
Synonyms
T palldm IgG CSF IF-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms like fatigue, weight loss, or unexplained infections, or if they suspect conditions such as multiple myeloma, lymphoma, or other bone marrow diseases. It can also be part of monitoring for these conditions.

What to Expect During the Test

A blood sample is drawn from a vein in your arm. The blood is processed to separate the plasma or serum, where the light chains are measured using a sensitive immunoassay method.

Sample Collection and Processing

The test uses a small amount of your blood, typically collected in a plain red-top tube. Plasma or serum is extracted and analyzed for free kappa and lambda light chains.

How Results Are Interpreted

Results are reported as separate measurements for kappa and lambda light chains. An imbalance or elevated levels may indicate abnormal antibody production, often linked to blood cancers or immune disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

High levels of free light chains, especially when one type (kappa or lambda) is disproportionately elevated, can signal multiple myeloma or other plasma cell disorders. It may also help diagnose or monitor conditions like amyloidosis or chronic lymphocytic leukemia.

Short name

Free Light Chains

Frequently asked questions

What causes abnormal free light chain levels?
Abnormal free light chain levels are most commonly associated with blood cancers like multiple myeloma or lymphoma. They can also occur in conditions affecting the immune system, such as amyloidosis, or in response to certain infections or medications.
How often should this test be repeated?
Your doctor will determine how often to repeat this test based on your symptoms, diagnosis, and treatment plan. If you have a known condition like multiple myeloma, follow-up tests may be scheduled every few months or as needed.
Can lifestyle changes affect free light chain levels?
While lifestyle factors like diet and exercise generally do not directly affect free light chain levels, managing underlying conditions (such as controlling blood pressure or managing infections) can indirectly support overall health, which may influence test results indirectly.
  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