[Diagnosis and Laboratory Follow-Up of Patients with Multiple Myeloma: Guidelines from the Portuguese Multiple Myeloma Group].

Multiple myeloma is a neoplasm of plasma cells that in most cases is associated with the secretion of monoclonal immunoglobulins and can involve multiple organs. Its timely diagnosis is essential to limit or avoid irreversible damage and dysfunction of target organs. Appropriate initial stratification of patients allows for optimization in the selection and sequence of therapy, as well as proper follow-up during treatment and monitoring, impacting survival. These laboratory guidelines from the Portuguese Multiple Myeloma Group provide recommendations for the diagnosis and laboratory follow-up of patients with multiple myeloma. The follow-up and diagnosis of patients with other clinically significant monoclonal gammopathies were not included in this text. This article was based on international guidelines, scientific publications, and the experience of a panel of specialists in clinical and laboratory fields dedicated to the study and treatment of multiple myeloma.