Why This Test Is Useful
Free light chains are fragments of antibodies produced in excess by abnormal plasma cells. This test is particularly sensitive for detecting light-chain-only myeloma (which standard protein electrophoresis can miss) and is useful for monitoring treatment response.Interpreting Results
| Finding | Significance |
|---|---|
| Abnormal kappa:lambda ratio | Suggests clonal plasma cell disorder |
| Elevated involved light chain with abnormal ratio | Supports myeloma or related disorder diagnosis |
| Normal ratio despite elevated total light chains | May reflect kidney disease (reduced clearance) rather than clonal disorder |
Kidney Function Affects ResultsBoth light chains are cleared by the kidneys, so kidney impairment can raise both levels — but the ratio (comparing the two types) usually remains more reliable for detecting a true clonal disorder.
Is this test the same as protein electrophoresis?
No — it's a complementary, often more sensitive test, particularly for detecting light-chain-only disease that standard electrophoresis might miss.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.