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Serum or Plasma Free Light Chain Kappa (Immunoassay)

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of free kappa light chains in your blood, which are small protein fragments produced by your immune system. These fragments can be elevated in certain blood disorders.

Quick summary

["Free kappa light chains help diagnose and monitor conditions like multiple myeloma or other plasma cell disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
11920-6
Short code
GA from FL.Hadlock84
Synonyms
GA from FL.Hadlock84
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-fl-hadlock
CPT
82553
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 a Free Light Chain Test Used For?

Free light chains are part of antibodies produced by plasma cells. When these cells become abnormal (as in multiple myeloma or other plasma cell dyscrasias), they may release excessive free light chains into the blood. Measuring these fragments helps doctors assess disease activity, monitor treatment progress, or diagnose conditions like monoclonal gammopathy of undetermined significance (MGUS).

How Is This Test Performed?

A blood sample is drawn from your arm, and the serum or plasma is tested using an immunoassay method to detect and quantify free kappa light chains. The test does not require fasting or special preparation beyond standard blood draw procedures.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like unexplained fatigue, bone pain, frequent infections, or if tests for other conditions (such as kidney function or complete blood count) show abnormalities. It’s also used in follow-up for patients with known plasma cell disorders.

What Do Results Mean?

Results are reported as a ratio of free kappa to free lambda light chains (kappa/lambda ratio). An elevated ratio may indicate an underlying plasma cell disorder. Your doctor will interpret results in the context of your medical history and other test results.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Free Kappa Light Chain

Frequently asked questions

This test is critical for diagnosing and managing conditions like multiple myeloma, where abnormal plasma cells produce excessive free light chains. It helps track disease progression and response to treatment by monitoring light chain levels over time.
What are free light chains? Free light chains are protein fragments released by plasma cells, which are white blood cells involved in making antibodies. In healthy people, these fragments are balanced between kappa and lambda types. If one type is abnormally high, it may signal a plasma cell disorder.
How long does it take to get results? Results are typically available within 24 to 48 hours, depending on lab processing times and your healthcare provider’s workflow.
Can I eat or drink before this test? You can eat and drink normally before this test, as it does not require fasting. However, follow any specific instructions your doctor or lab provides.
Is there any risk or discomfort with this test? The blood draw may cause mild discomfort or bruising at the site, but there are no major risks. If you have a hard time with blood draws, let your doctor know.
Can this test be done at home? No, this test requires a blood sample collected in a clinical setting by a healthcare professional. Home-based tests for light chains are not currently available.
  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 17, 2026. · Read our editorial policy