Lambda Light Chains - Free, Serum

Antibodies are proteins made by plasma cells to help the body fight infections. Each antibody contains two types of protein parts called heavy chains and light chains. Light chains are of two types: kappa and lambda. During normal antibody production, a small amount of extra light chains enters the bloodstream as free light chains. While low levels are normal, abnormal levels may be associated with plasma cell disorders, immune system conditions, or kidney problems.

The Lambda Light Chains - Free, Serum test specifically measures the level of free lambda light chains in the serum. Elevated levels may occur when abnormal plasma cells produce excessive amounts of lambda light chains, as seen in conditions such as multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), light chain myeloma, Waldenström macroglobulinemia, and AL amyloidosis. These abnormal proteins may accumulate in the body and affect organs such as the kidneys, bones, nerves, or heart.

The test is commonly performed along with kappa light chains and the kappa/lambda free light chain ratio. Evaluating both light chains together helps doctors determine whether abnormal results are caused by a plasma cell disorder, such as multiple myeloma, or are related to other conditions such as infection, inflammation, or kidney dysfunction.

Doctors may recommend the Lambda Light Chains - Free, Serum test for individuals with symptoms such as persistent bone pain, unexplained fractures, fatigue, anemia, recurrent infections, weight loss, numbness, kidney problems, or abnormal protein findings on blood or urine tests. It is also useful for monitoring treatment response and disease progression in individuals already diagnosed with plasma cell disorders.