The impact of renal function on the clinical performance of FLC measurement in AL amyloidosis

Abstract

AbstractThe measurement of circulating free light chains (FLC) is of utmost importance in immunoglobulin light chain (AL) amyloidosis, being a fundamental part of the diagnostic workup, prognostic stratification and assessment of response to therapy. Renal failure is a common feature of AL amyloidosis and can considerably affect the concentration of FLC.We assessed the impact of renal failure on the clinical performance of the Freelite assay in 982 consecutive, newly diagnosed patients with AL amyloidosis, 822 with estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 mThe diagnostic sensitivity of the κ/λ FLC ratio was lower for λ amyloidogenic FLC in patients with renal failure (81% vs. 60%, p<0.001) and the FLC concentration had no independent prognostic significance in patients with severe renal dysfunction. However, FLC response to chemotherapy could still discriminate patients with better outcome.Renal failure is a relevant interference factor when using the Freelite assay for the identification of the amyloidogenic light chain and for prognostic assessment in patients with AL amyloidosis and renal failure.