Serum free light chains test
Quick answer: This test measures free kappa and lambda light chains, parts of antibodies made by plasma cells, in your blood. Doctors order it to help diagnose and monitor myeloma and related plasma cell disorders.
- SampleBlood
- TakesAbout 5 minutes
- Before the testNo special preparation is usually needed.
How the test is done
- 1You sit and the inside of your elbow is cleaned
- 2A needle draws blood into a tube
- 3The lab measures kappa and lambda light chains
- 4The kappa to lambda ratio is calculated
What your results can mean
Reading your report
The kappa-to-lambda ratio is read with other tests and kidney function, so discuss it with your doctor.
If the result is outside the usual range
An abnormal kappa to lambda ratio can point to myeloma, amyloidosis or related plasma cell conditions. Both light chains can rise with kidney disease or inflammation while the ratio stays normal.
Who usually has this test
People with suspected or known myeloma or related conditions, and people with unexplained kidney problems or protein in urine.
Risks and aftercare
Mild bruising is possible but uncommon.
Names and options
Also called: FLC, kappa lambda ratio, free light chain
Options
- Kappa and lambda
- Lambda only
Listed by the hospital as
- FREE LIGHT CHAINS, SERUM
- FREE LIGHT CHAIN, LAMBDA, SERUM
Questions about this test
Why is the kappa to lambda ratio important?
Normally both are made in balance. A clearly abnormal ratio suggests one group of plasma cells is making too much.
Can kidney disease affect free light chains?
Yes. The kidneys clear light chains, so kidney disease raises both. The ratio range is sometimes adjusted for this.
Is this test used to monitor myeloma treatment?
Yes. Changes in the involved light chain can help show how well treatment is working.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
Get directions ↗IVF Pulse fertility care at Tamara Hospital →
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.