Severe hyperphosphatemia in a patient with chronic kidney disease and multiple myeloma-to strengthen the case toward renal replacement therapy?

KEY CLINICAL MESSAGEWe report a patient with multiple myeloma and chronic kidney disease who presented with severe hyperphosphatemia in the outpatient clinic without any related symptoms. Initial differential diagnosis: Tumor lysis syndrome or chronic kidney disease. Further work-up revealed pseudohyperphosphatemia. In general, treatment is not necessary if the true phosphate level is within the reference range and the patient is asymptomatic.