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Urine Free Light Chain Immunoassay (Quantitative)

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

This test measures the amount of free light chains (light parts of antibodies) found in your urine. Free light chains can be elevated in conditions affecting plasma cells, such as multiple myeloma or other blood-related disorders.

Quick summary

["This test helps diagnose or monitor certain blood disorders by detecting abnormal protein fragments in urine."]

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

Key facts at a glance

LOINC
93452-1
Short code
W-19 Ur Cfm-mCnc
Synonyms
W-19 Ur Cfm-mCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
confirm
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like unexplained fatigue, frequent infections, bone pain, or if they suspect conditions like multiple myeloma, lymphoma, or other plasma cell disorders. It may also be used as part of routine monitoring for patients already diagnosed with these conditions.

What to Expect Before the Test

No special preparation is needed for this urine test. You may collect a random urine sample at any time of day. If you’re taking certain medications that could affect urine color or flow, let your provider know.

What the Test Results Mean

Results are typically reported as a concentration value (e.g., mg/L). High levels of free light chains in urine can indicate plasma cell disorders, while normal levels suggest no significant abnormalities. Your provider will interpret results in the context of your overall health and symptoms.

Common Conditions Monitored

This test is primarily used to diagnose or monitor multiple myeloma, plasma cell leukemia, and other conditions where abnormal plasma cells produce excessive free light chains.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Elevated Free Light Chains in Urine

Short name

Urine Free Light Chain Test

Frequently asked questions

What causes elevated free light chains in urine?
Elevated free light chains in urine are most commonly associated with multiple myeloma, where abnormal plasma cells in the bone marrow produce too many light chains. These chains can then appear in urine. Other conditions, such as lymphoma or certain infections, may also cause temporary increases. If you notice unexplained symptoms like frequent infections, bone pain, or fatigue, discuss these findings with your provider.
How often should I get this test?
The frequency of this test depends on your diagnosis and healthcare provider’s recommendations. If you have a known plasma cell disorder, your provider may order this test regularly to monitor disease progression or response to treatment. Follow-up schedules are tailored to your specific situation.
Can diet or medications affect urine free light chain test results?
While diet generally does not directly affect urine free light chains, certain medications (like some chemotherapy drugs or diuretics) may influence urine production or composition. Always inform your provider about all medications, supplements, or recent changes in diet before testing.
  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