Quantification of polyclonal free light chains in clinical samples using a single turbidimetric immunoassay.

Background: Elevated polyclonal serum free light chain (FLC) levels have been associated with increased mortality and disease activity in many conditions. Currently, polyclonal FLC quantification requires summation of individual FLCκ and FLCλ assays. Here we present a single assay for combined FLC (cFLC, Combylite) which reduces assay time and eliminates potential imprecision errors incurred by summating FLC assays (ΣFLC).