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Serum or Plasma Free Light Chain Immunoglobulin (λ) Measurement

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

This test measures the amount of free light chain (λ) proteins in your blood, which can help diagnose certain conditions affecting the immune system or kidneys.

Quick summary

["Free λ light chains help identify abnormal immune or kidney function."]

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

Key facts at a glance

LOINC
63349-5
Short code
ENA SS-B Ab Fld Ql ID
Synonyms
ENA SS-B Ab Fld Ql ID
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
immune-diffusion
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 to check for conditions like multiple myeloma, lymphoma, or other blood disorders where abnormal light chains are produced. It can also help monitor kidney function or detect signs of immune system issues over time.

What Does the Result Mean?

Results may be compared to a standard reference range for healthy individuals, though exact values can vary by lab. Elevated levels may suggest conditions like multiple myeloma or kidney disease, while low levels might indicate other immune-related disorders.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum or plasma for testing. This test does not require fasting.

Common Conditions Monitored

This test is often used to monitor multiple myeloma, plasma cell dyscrasias, or kidney function in patients with known immune disorders. It may also help diagnose or track progression of conditions like amyloidosis or certain lymphomas.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free λ Light Chain

Frequently asked questions

What does a high or low result mean?
A high level of free λ light chains may signal an overproduction of these proteins, often linked to conditions like multiple myeloma or kidney problems. Your doctor will interpret results in the context of your medical history and other tests.
Does this test require fasting?
No fasting is required for this test. Blood is drawn at a time that is convenient for you, and the sample is processed immediately for analysis.
How often should I get this test?
Frequency depends on your diagnosis and treatment plan. Your healthcare provider will determine how often this test should be done, often as part of ongoing monitoring for conditions like multiple myeloma or kidney disease.
  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