[Difficulties in the identification of serum M-component].

The essential criteria for M-component identification , according to precise M-component definition based on literature data, are cited. Problems and difficulties in M-component identification are illustrated on selected cases. It is pointed out that, beside of M-component, IgA/albumin (fig. 3) as well as Ig/anti IgG soluble complexes (fig. 6) may occasionally have the appearence of electrophoretically homogeneous serum protein fraction: if this is suspected the true nature of homogeneous fraction must be further elucidated. In addition, it is stressed that lipoprotein specific staining of electropherogramms, can be very helpfull in the detection of small or abscure serum M-components (fig. 5).