[Laboratory investigation on M-protein and its clinical application. 1. Introduction].

Monoclonal protein is the immunoglobulin and its fragments which are originated from a monoclonal clone of immunoglobulin synthesizing cell. It is an actually tumour marker for B cell lymphoproliferative disorders. It is also observed in non-lymphoproliferative disorders such as solid tumor, infection, and immunodeficiencies. Monoclonal gammopathy of undetermined significance(MGUS) can be defined as a state of pre-malignancies, especially development of myeloma should be carefully followed. The paper outlines a routine-based laboratory approach on monoclonal protein in relevance with its classification, laboratory methods and the related diseases, thus giving general orientations for the paper followed.