title: Quantitative serum free light chain assay in the diagnostic evaluation of AL amyloidosis.
abstract: We compared a new serum immunoassay for quantitation of serum free light chains (FLC) with the conventional tests for clonal immunoglobulin production: bone marrow immunohistochemistry, serum immunofixation electrophoresis, and urine immunofixation electrophoresis. Serum samples from 169 patients with AL amyloidosis and 20 controls were examined. Elevated levels of kappa-FLC and lambda-FLC were found in 94% and 93% of patients with the respective clonal disease. However, false positive elevations of kappa-FLC and lambda-FLC were found in 30% and 44% of patients with clonal disease of the other light chain subtype. We found that the FLC level was a reliable test for the diagnosis of clonal disease when the FLC kappa:lambda ratio was abnormal and was comparable to the conventional tests in patients with AL amyloidosis. After a histologic tissue diagnosis of amyloidosis, determining the type as AL amyloidosis relies on a panel of hematologic tests to determine light chain clonality and the exclusion other forms of amyloidosis.
authors.affiliation: Amyloid Treatment and Research Program at Boston Medical Center, Boston University School of Medicine, Boston, MA, 02118, USA.
authors.forename: Harun
authors.initials: H
authors.lastname: Akar
authors.forename: David C
authors.initials: DC
authors.lastname: Seldin
authors.forename: Barbarajean
authors.initials: B
authors.lastname: Magnani
authors.forename: Carl
authors.initials: C
authors.lastname: O'Hara
authors.forename: John L
authors.initials: JL
authors.lastname: Berk
authors.forename: Christopher
authors.initials: C
authors.lastname: Schoonmaker
authors.forename: Howard
authors.initials: H
authors.lastname: Cabral
authors.forename: Laura M
authors.initials: LM
authors.lastname: Dember
authors.forename: Vaishali
authors.initials: V
authors.lastname: Sanchorawala
authors.forename: Lawreen H
authors.initials: LH
authors.lastname: Connors
authors.forename: Rodney H
authors.initials: RH
authors.lastname: Falk
authors.forename: Martha
authors.initials: M
authors.lastname: Skinner
mesh_terms: D000328:Adult; D000368:Aged; D000686:Amyloidosis / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007145:Immunoglobulin kappa-Chains / Q000097:blood*; D007146:Immunoglobulin lambda-Chains / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry / Q000379:methods; D012680:Sensitivity and Specificity
chemical_list: D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains