Diagnostic value of the concentration of M‐component in initial classification of monoclonal gammopathy

Abstract

The diagnostic value of the concentration of a serum M‐component in initial classification of monoclonal gammopathy into malignant monoclonal gammopathy (MMG) and monoclonal gammopathy of undetermined significance (MGUS) was evaluated in 315 consecutive individuals with IgG, IgA or IgM type M‐components. The final diagnosis was MMG in 84 and MGUS in 231 patients. Serum concentration was significantly highest in MMG, but for all 3 kinds of M‐components, overlapping serum concentrations between MMG and MGUS were found. Highest efficiency was reached with a serum concentration of 30.2 g/l for IgG, 26.6 g/l for IgA and 22.7 g/l for IgM. Using these values, an initial correct classification was achieved in 0.90 of IgG M‐components, in 0.91 of IgA M‐components and in 0.79 of IgM M‐components. Normal levels of uninvolved immunoglobulins were found to point strongly to MGUS.

Protein characterization using electrophoresis and immunofixation; a case‐based review of dogs and cats

“…Monoclonal gammopathy of undetermined significance (MGUS) is a diagnostic category often used in human patients and describes the presence of a distinct M‐protein peak without concurrent evidence of a neoplastic population. It typically has a lower concentration of M‐protein, could be associated with chronic antigenic stimulation and is considered a premalignant state requiring life‐long monitoring . The incidence of MGUS in veterinary species is unknown, possibly because veterinary medicine does not use the same screening strategies used for human patients.…”