Development of a "Myeloma Risk Score" using a population-based registry on paraproteinemia and myeloma.

Diagnostic systems for monoclonal gammopathies use bone marrow and X-ray examinations to exclude multiple myeloma (MM). Data from a population-based registry of unselected patients with paraproteinemia indicate that these tests are often done only when MM is suspected. We used 441 randomly selected patients to develop a simple four point "Myeloma Risk Score" based on two readily available laboratory tests. One point was given for paraprotein concentration > or = 10 g/l, one point for IgG and IgA, and two points for IgD and light chains only. A score of 0 or 1 indicated a low risk for MM, with scores of 2 and 3 signifying high risks. Sensitivity, specificity, positive and negative predictive value (PV) for the Myeloma Risk Score in the training sample were 92%, 88%, 79%, and 96% respectively. Extrapolating these results to a larger cohort showed that 90% of patients with a monoclonal gammopathy could be classified correctly as having MM or a non-myeloma condition. The Myeloma Risk Score can identify patients with a paraproteinemia at risk for MM, and who are therefore candidates for bone marrow and X-ray examination.