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Serum or Plasma Free Light Chain Immunoassay (Free Kappa and Lambda Light Chains)

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

This test measures the free light chains (kappa and lambda) produced by plasma cells, which are part of the immune system. It helps detect conditions affecting these cells, such as multiple myeloma or other plasma cell disorders.

Quick summary

["This test helps identify abnormal immune cell activity that may signal underlying diseases."]

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

Key facts at a glance

LOINC
98220-7
Short code
T palldm IgG CSF Ql IB
Synonyms
T palldm IgG CSF Ql IB
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ib
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 healthcare provider may order this test if you have symptoms like unexplained fatigue, frequent infections, bone pain, or kidney problems. It’s also used to monitor conditions like multiple myeloma, lymphoma, or other blood disorders that affect plasma cells.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw, and the sample will be sent to a lab for analysis. If you’re on certain medications, let your provider know—some may affect results.

How the Test Works

Blood is drawn, and the serum or plasma is tested for free kappa and lambda light chains using an immunoassay method. This detects abnormal levels that may indicate plasma cell disorders.

Possible Results and Their Meaning

Results show separate measurements for kappa and lambda light chains. Elevated levels of one type (or an imbalance between them) may signal conditions like multiple myeloma, amyloidosis, or other plasma cell diseases.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: What It Means for Your Health

Short name

Free Light Chains

Frequently asked questions

High levels of free light chains can indicate overproduction by plasma cells, often linked to cancers like multiple myeloma or benign conditions like monoclonal gammopathy of undetermined significance (MGUS). Monitoring these levels helps track disease progression or response to treatment.
This test is not a standalone diagnosis but a key part of evaluating suspected plasma cell disorders. Results may prompt further testing, such as bone marrow biopsy or additional bloodwork.
What if my results are abnormal?
If your results are abnormal, your doctor will discuss next steps, which may include more tests or a follow-up visit. They may also adjust treatment plans if applicable.
Does this test affect my medications?
Generally, no. However, if you’re on medications that suppress the immune system or affect blood cell production, your provider may adjust your treatment based on these findings.
  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