Serum-free light-chain assay: clinical utility and limitations.
In the last decade, the introduction of the serum-free light-chain (sFLC) assay has been an important advance in the diagnosis and management of plasma cell dyscrasias, particularly monoclonal light-chain diseases. The immunoassay was developed to detect free light chains in serum by using anti-FLC antibodies which specifically recognised epitopes on light chains that were 'hidden' in intact immunoglobulins. Since its introduction in 2001, there have been several publications in the English language literature discussing the clinical utility as well as analytical limitations of the sFLC assay. These studies have highlighted both positive and negative aspects of the assay particularly with regard to its sensitivity and specificity and the technical challenges that can affect its performance. The contribution and significance of the sFLC assay in the management of light-chain myeloma, primary amyloid light-chain (AL) amyloidosis and non-secretory myeloma are well recognised and will be addressed in this review. The aim of this article is to also review the published literature with a view to providing a clear understanding of its utility and limitations in the diagnosis, prognosis and monitoring of plasma dyscrasias including intact immunoglobulin multiple myeloma (MM) and monoclonal gammopathy of unknown significance (MGUS). The increasing interest in using this assay in other haematological conditions will also be briefly discussed.
Department of Immunology, Russells Hall Hospital, The Dudley Group NHS Foundation Trust, Dudley, UK malini.bhole@nhs.net.
Malini V
MV
Bhole
Department of Immunology, Churchill Hospital, Oxford Radcliffe NHS Trust, Oxford, UK.
Ross
R
Sadler
Department of Haematology, Churchill Hospital, Oxford Radcliffe NHS Trust, Oxford, UK Department of Haematology, Royal Berkshire Hospital NHS Foundation Trust, Reading, UK National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, Headington, UK.
Karthik
K
Ramasamy
D000686:Amyloidosis / Q000097:blood*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007147:Immunoglobulin Light Chains / Q000097:blood*; D000075363:Immunoglobulin Light-chain Amyloidosis; D009101:Multiple Myeloma / Q000097:blood; D009391:Nephelometry and Turbidimetry / Q000379:methods; D010265:Paraproteinemias / Q000097:blood* / Q000175:diagnosis; D011379:Prognosis; D012016:Reference Values
D007147:Immunoglobulin Light Chains
Laboratory methods; analytical systems; immunoassay