Pseudohyperphosphatemia

Objective: To review instances of spurious elevation of inorganic phosphate measurements due to interference with analytical methods. Methods: Selective literature review. Results: Depending on the method used to measure inorganic phosphate, several factors have been reported to produce spurious elevations, including paraproteinemia, hyperlipidemia, hemolysis, and hyperbilirubinemia. Of these, paraproteinemia is probably the commonest. Conclusion: Both clinical biochemists and clinicians should be aware of the phenomenon of pseudohyperphosphatemia. Clinically unexplained persistent hyperphosphatemia should initiate a search for potential causes of pseudohypophosphatemia, especially paraproteinemia.