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Serum/plasma free light chains (kappa and lambda) with quantitative trends over time

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

This test measures the levels of free kappa and lambda light chains in your blood, which are small protein fragments produced by your immune system. These fragments can be elevated in certain conditions affecting your plasma cells.

Quick summary

["Light chains help doctors diagnose and monitor conditions like multiple myeloma or other plasma cell disorders."]

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

Key facts at a glance

LOINC
111904-9
Short code
Fnl apprch dp cannl Blry tr Endscpy
Synonyms
Fnl apprch dp cannl Blry tr Endscpy
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
endoscopy
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 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 may also be used to monitor treatment progress in conditions where plasma cells are abnormal, such as multiple myeloma or lymphoma.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Free light chains are normally present in small amounts. Elevated levels can indicate conditions like multiple myeloma, where too many plasma cells produce these fragments. Your provider will interpret results in the context of your symptoms and other tests.

Common Conditions Monitored

This test helps diagnose or track conditions such as multiple myeloma, amyloidosis, or other plasma cell dyscrasias (abnormalities in plasma cells). It can also be used to assess kidney function indirectly, as light chains can affect kidney health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Free Light Chain Test

Frequently asked questions

How often will I need this test?
The frequency depends on your condition. If you have a known plasma cell disorder, your provider may order this test regularly to check for changes in your light chain levels, which can help guide treatment decisions.
Can I eat or drink before the test?
You can eat and drink normally unless your provider gives specific instructions. Avoiding food or fluids for a set period is not required for this test.
What are the normal ranges for this test?
There are no fixed numeric ranges provided here. Your provider will compare your results to your baseline and clinical picture to determine if levels are within expected limits or if further action is needed.
  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