Kappa Free Light Chains

The kappa (κ) and lambda (λ) free light chains are produced by plasma cells, and their abnormal production is a hallmark of several hematological diseases.

In multiple myeloma, malignant plasma cells often produce excessive amounts of one type of free light chain, either kappa or lambda, leading to an abnormal kappa/lambda ratio. The measurement of FLCs can detect monoclonal production of light chains, which is crucial for diagnosing both typical and atypical forms of multiple myeloma.

A subtype of myeloma, light chain multiple myeloma, predominantly secretes light chains rather than intact immunoglobulins. FLC assays are essential for diagnosing this form, as traditional serum protein electrophoresis might not detect the monoclonal proteins effectively.

Some cases of multiple myeloma, known as nonsecretory myeloma, do not produce detectable levels of monoclonal proteins in serum or urine by standard methods. FLC measurement can often reveal the presence of monoclonal free light chains, thus aiding in diagnosis.

FLC levels are monitored during treatment to assess the effectiveness of therapy. A significant reduction in abnormal FLCs suggests a good response to treatment, whereas rising levels may indicate disease progression or relapse.