RESUMO
OBJECTIVE: To discuss the diagnosis and management of paraprotein interference in the setting of multiple myeloma (MM). METHODS: We discuss the evaluation of hypophosphatemia in a patient with MM and present a review of the relevant literature. RESULTS: Our patient, who had a history of MM, was found to have persistently undetectable serum phosphate which did not respond to aggressive phosphate replacement. His clinical condition was not consistent with severe phosphate depletion and hence paraprotein interference secondary to MM was suspected. Re-analyzation of samples on a different machine showed normal serum inorganic phosphate levels. CONCLUSION: Paraprotein interference from MM causing pseudohypophosphatemia can be overlooked and lead to unnecessary treatment. Recognition of this phenomenon is important to all clinicians, especially in light of potential complications of unnecessary treatment.