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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 (small protein fragments) in your blood, which can help diagnose conditions like multiple myeloma or other blood disorders.

Quick summary

["Free light chains help doctors check for hidden blood diseases or monitor treatment progress."]

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

Key facts at a glance

LOINC
96486-6
Short code
NIF IgG Ser Ql IF
Synonyms
NIF IgG Ser 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
CPT
82784
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 Is This Test Done?

Your healthcare provider may order this test if you have symptoms like unexplained fatigue, frequent infections, or kidney problems. It’s also used to monitor conditions like multiple myeloma, lymphoma, or other hematologic disorders.

What Does the Test Measure?

The test detects free light chains (κ or λ), which are parts of antibodies broken down in the body. High levels may indicate a blood cancer or immune system issue.

How Is the Test Performed?

A blood sample is drawn, and the free light chains are measured using an immunoassay method to identify their concentration.

What Are the Results?

Results are compared to reference ranges for healthy individuals, though exact values may vary by lab. Elevated levels may signal a need for further testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Free light chains are normally produced in small amounts. Abnormal elevations can signal conditions like multiple myeloma, Waldenström macroglobulinemia, or other plasma cell disorders. Low levels may rarely indicate immune deficiencies or certain genetic disorders.

Short name

Free Light Chain Test

Frequently asked questions

What causes abnormal free light chain levels?
Abnormal levels are most commonly linked to blood cancers (e.g., multiple myeloma) or other plasma cell disorders. Rarely, they may be elevated in chronic infections, autoimmune diseases, or kidney problems.
How often should I get this test?
Your doctor will determine frequency based on your medical history, symptoms, and treatment plan. Regular monitoring may be needed if you have a known blood disorder.
Does this test require fasting?
No fasting is required, but follow your doctor’s instructions for any medications or lifestyle adjustments before the test.
  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