Free Light Chains Test
A free light chains test measures the level of free light chains in your blood. These are proteins made by plasma cells. The test helps diagnose or monitor plasma cell disorders like multiple myeloma and amyloidosis.
What this test measures
The test measures the amount of two types of free light chains (kappa and lambda) in your blood and calculates their ratio.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
A higher than normal level of free light chains may be a sign of a plasma cell disorder such as multiple myeloma, amyloidosis, MGUS, or Waldenstrom macroglobulinemia. It can also be due to a kidney condition.
Frequently asked questions
What are free light chains?
Free light chains are extra light chain proteins made by plasma cells that are not bound to heavy chains. They are released into the bloodstream.
What does the free light chains test measure?
It measures the levels of kappa and lambda free light chains in your blood and provides a ratio of the two.
Why is this test done?
It is used to help diagnose or monitor treatment of plasma cell disorders such as multiple myeloma and amyloidosis.
What do abnormal results mean?
Abnormal results may indicate a plasma cell disorder like multiple myeloma, amyloidosis, MGUS, or Waldenstrom macroglobulinemia. High levels can also be due to kidney disease.
How are results interpreted?
Your provider will consider your symptoms, medical history, and other blood test results to understand what your free light chain levels mean.
Related lab tests
Sources
- MedlinePlus: Free Light Chains — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.