Role of CRAB Criteria as Modality for Prediction of State of Multiple Myeloma

Abstract

Multiple myeloma is a malignancy of plasma cells originating from the bone marrow; it is a clonal plasma cell disorder that produces excess monoclonal immunoglobulin. The disease most commonly presents with hypercalcemia, renal failure, anemia and bone lesions (CRAB features).

Myeloma is preceded by an indolent phase termed monoclonal gammopathy of undetermined significance (MGUS), which is defined by the presence of a monoclonal protein (<3 g/dL) without any end organ damage or features of myeloma. The cause of MGUS is currently unknown, but this disorder can evolve into symptomatic myeloma. The risk of progression to myeloma is about 1% per year, with risk factors being a high monoclonal protein level, high percentage of plasma cells in the bone marrow, presence of IgA monoclonal protein, and an abnormal free light chain ratio.6 The prevalence of MGUS increases with age, with 3.2% of cases presenting in persons aged over 50 years, and 5.3% of cases in persons aged over 70 years.