Skip to content

Serum or plasma free light chains (total)

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

This test measures the total amount of free light chains (small protein fragments) in your blood, which can help diagnose conditions affecting plasma cells (cells that produce antibodies).

Quick summary

["Free light chains help identify disorders like multiple myeloma or other plasma cell dyscrasias."]

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

Key facts at a glance

LOINC
10115-4
Short code
ST wave ED L-V4
Synonyms
ST wave ED L-V4
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ekg
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

What Is Free Light Chain Testing Used For?

Free light chains are produced by plasma cells, which are part of the immune system. When these cells become abnormal (e.g., in multiple myeloma or other plasma cell disorders), they may release excess free light chains into the blood. Measuring these helps doctors track disease activity, monitor treatment, or diagnose conditions like monoclonal gammopathy of undetermined significance (MGUS).

How Is This Test Performed?

A blood sample is drawn, and the serum or plasma is analyzed using an immunoassay method to detect and quantify free light chains. This test is typically done as part of a broader evaluation for suspected plasma cell disorders.

When Might You Need This Test?

Your doctor may order this test if you have symptoms like unexplained fatigue, bone pain, or high calcium levels, or if they suspect conditions like multiple myeloma, amyloidosis, or MGUS. It’s also used during follow-up to monitor treatment progress.

What Are Common Results and Their Meanings?

Results are compared to reference ranges for healthy individuals. Elevated levels may indicate plasma cell disorders, while normal or low levels suggest no significant abnormality. Your doctor will interpret results in the context of your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Free Light Chains

Frequently asked questions

Why do doctors check for free light chains in blood tests?
Doctors check for free light chains to detect and monitor conditions like multiple myeloma, where abnormal plasma cells produce too many light chains. These chains can build up in the blood or kidneys, causing symptoms or complications.
How often should I get this test if I have a plasma cell disorder?
The frequency depends on your diagnosis and treatment plan. Your doctor may recommend regular testing (e.g., every few months) to track disease progression or response to treatment.
Can diet or supplements affect free light chain levels?
Diet or supplements typically do not directly affect free light chain levels, but they can influence overall health. Always discuss any changes with your doctor before starting new supplements.
  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