摘要 : Background: Multiple myeloma (MM) accounts for approximately 10% of hematological malignancies. The monoclonal immunoglobulin G kappa (IgG-kappa) daratumumab can bind to CD38 on MM cells and be detected in serum immunofixation (IF... 展开 Background: Multiple myeloma (MM) accounts for approximately 10% of hematological malignancies. The monoclonal immunoglobulin G kappa (IgG-kappa) daratumumab can bind to CD38 on MM cells and be detected in serum immunofixation (IF), causing pitfalls in M-protein quantification. Objectives: To determine the efficacy of mitigating the interference of IgG MM treated with daratumumab. Methods: Levels of Ig, free light chains (FLC) kappa (kappa) and lambda (lambda), serum protein electrophoresis (SPE)/IF, and Hydrashift 2/4 assays were assessed following manufacturers instructions in three patients. Results: Patient 1 was a 70-year-old male diagnosed with IgG-lambda MM. The IF distinguished two monoclonal bands (IgG-kappa and IgG-lambda). With the Hydrashift assay, the daratumumab-anti-da-ratumumab immune complex shifted the IgG-kappa to the alpha zone, suggesting that the monoclonal IgG-kappa band corresponded to daratumumab. Patient 2 was a 63-year-old male with IgG-kappa MM who was receiving daratumumab once every other week. SPE/IF assay revealed a faint monoclonal IgG-kappa band in the y zone. A stronger monoclonal band was observed after administration. The IgG-kappa band disappeared on the Hydrashift assay, while the daratumumab-anti-daratumumab complex appeared as a broad smear in the alpha-region. Patient 3, a 63-year-old male diagnosed with IgG-lambda MM, was receiving daratumumab once every other month. The IF assay showed two distinct bands (IgG-kappa and IgG-lambda) post-daratumumab administration. The shift to the alpha zone of the IgG-kappa bands on the Hydrashift assay confirmed that the addition-al band observed post-infusion was due to the daratumumab. Conclusions: The Hydrashift assay can help distinguish dara-tumumab from endogenous M-spike. 收起