Light chains are proteins made by plasma cells, a type of white blood cell. Plasma cells also make immunoglobulins (antibodies). Immunoglobulins help protect the body against illness and infections. Immunoglobulins are formed when light chains link up with heavy chains, another type of protein. When light chains link up with heavy chains, they are known as bound light chains.
Normally, plasma cells make a small amount of extra light chains that don’t bind with heavy chains. They are instead released into the bloodstream. These unlinked chains are known as free light chains.
There are two types of light chains: lambda and kappa light chains. A free light chains test measures the amount of lambda and kappa free light chains in the blood. If the amount of free light chains is higher or lower than normal, it can mean you have a disorder of the plasma cells. These include multiple myeloma, a cancer of plasma cells, and amyloidosis, a condition that causes a dangerous buildup of proteins in different organs and tissues.
Other names: free kappa/lambda ratio, kappa/lambda quantitative free light, freelite, kappa and lambda free light chains, immunoglobulin free light chains