Algorithm for Investigation of IgM Monoclonal Protein.* Laboratory studies include CBC, serum calcium, creatinine, β-2-microglobulin, LDH, liver enzymes, serum protein electrophoresis with immunofixation, serum free light chain assay, quantitative immunoglobulins, 24-hour urine testing for protein, and urine electrophoresis.** Skeletal survey is the preferred first-line imaging choice.◆ Marrow evaluation includes immunohistochemical studies, flow cytometry, conventional cytogenetics, and myeloma FISH.✝ Confirm by MYD88 sequence analysis.