Kappa and Lambda - Freelite, Serum

Serum Free Light Chains Overview

The serum free light chain test, also known as the SFLC blood test or free light chain assay test, measures the levels of unbound immunoglobulin light chain molecules in the blood. These light chains, named kappa and lambda, are components of antibodies (immunoglobulins) produced by plasma cells, a type of white blood cell found in the bone marrow. Normally, light chains link with heavy chains to form complete antibodies. However, when there are more light chains than heavy chains, these extra light chains are released into the bloodstream as "free" light chains.

The free light chain test is crucial for detecting and monitoring conditions related to plasma cell disorders, such as multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), and amyloidosis. It provides valuable insights into the functioning of plasma cells and helps in the diagnosis and management of these conditions.

Kappa and Lambda-Free Light Chains (FLC) are proteins produced by immune cells called plasma cells. They are released into the bloodstream and can be measured using laboratory tests. When plasma cells become cancerous or abnormal, they can produce an excessive amount of either kappa or lambda FLCs, causing an imbalance in the ratio of kappa to lambda FLCs in the bloodstream. This imbalance can be detected using a test called the kappa/lambda FLC ratio.

The kappa/lambda FLC ratio is used in conjunction with other tests to help diagnose and monitor plasma cell disorders including multiple myeloma, Waldenström macroglobulinemia, and amyloidosis. It can also be used to assess the risk of progression from monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma.

Written By: Supriya Kulkarni, Lead-Content & Training

Reviewed By: Dr. Alap Christry M.D. AVP-Lab Operations & Scientific Business Head-Clinical Chemistry