Serum-free light chains in the evaluation of M-component disease.

Current guidelines recommend screening with serum M-protein and serum-free light chain analysis (S-FLC) when an M-protein-related disorder is suspected. Many patients with multiple myeloma will be overlooked if only serum M-protein is measured. Despite this, the general practitioners in some areas of Denmark cannot order S-FLC. This review aims to disseminate knowledge of the S-FLC analysis, its applicability, and limitations in the diagnostic workup for suspected monoclonal gammopathies.