“…To overcome some possibilities of error, researchers accredited heavy/light chain (HLC) assay (Hevylite -Binding Site, Birmingham, UK), pairing heavy and light myeloma chains with undiseased ones to undoubtedly define clonal residue (e.g. in patients with IgG-k MM, measuring IgGλ, IgA-k and IgAλ), but the small number of works on the Hevylite method has not yet allowed definition of its potential in terms of prognosis Ludwig, Durie, et al, 2012;Ludwig, Slavka, et al, 2012;Ludwig, Milosavljevic, et al, 2013;Ludwig, Viterbo, et al, 2013;Tovar et al, 2012). Furthermore, in infection or rheumatological disease, determination of the FLC should not be performed, because of its expression of regained jurisdiction of the immune system, which occurs in the healed disease; also in patients with renal impairment, in which FLC ratio is altered due to slower renal clearance of λ-light chain for its dimeric structure, and double production rate of κ-light chain, their use is limited (Hutchison et al, 2008).…”