摘要 : BackgroundPseudohyperphosphatemia is a rare laboratory finding in MM, especially in patients with smoldering myeloma (SMM) progressing to symptomatic multiple myeloma (MM). Laboratorians and clinicians should be aware of this phen... 展开 BackgroundPseudohyperphosphatemia is a rare laboratory finding in MM, especially in patients with smoldering myeloma (SMM) progressing to symptomatic multiple myeloma (MM). Laboratorians and clinicians should be aware of this phenomenon and take necessary actions to avoid misdiagnosis. MethodsSpecimens from a monoclonal IgG kappa SMM patient with extremely high serum phosphorus concentrations measured by the Roche phosphomolybdate assay were re-evaluated using serial dilutions and the ORTHO VITROS assay free from monoclonal gammaglobulin interference. Serum free kappa/lambda chain ratio was also assessed. ResultsBoth serial dilutions and the ORTHO VITROS assay normalized serum phosphorus concentrations, suggesting the extremely high serum phosphorus concentrations measured by the Roche assay is due to interference from monoclonal gammaglobulin. Additionally, the patient's serum free kappa/lambda ratio was >100. Based on serum free kappa/lambda ratio, disease progression from SMM to MM was diagnosed. ConclusionsPrompt and appropriate laboratory investigations ensure correct diagnosis of pseudohyperphosphatemia and help clinicians properly manage patients. To our knowledge, this patient is the first reported case of pseudohyperphosphatemia in patients with progression from SMM to MM. 收起