Severe Hyperphosphatemia in a Patient with Mild Acute Kidney Injury

Table 3

Causes of pseudohyperphosphatemia.

Causes	Mechanisms
Liposomal amphotericin (or any drug requiring liposomal bilayer formulation)	Hydrolysis of phosphate from the liposomal bilayer at the low pH used in the assay to measure phosphorus leads to falsely high readings for serum phosphorus
Paraproteinemia (multiple myeloma, Waldenstrom macroglobulinemia, monoclonal gammopathy of undetermined significance)	Precipitation of paraproteins and associated turbidity may interfere with light absorbance by ultraviolet spectrophotometry, thus readings for phosphorus concentration. Excess binding of phosphate to certain paraproteins and specific physiochemical characteristics of paraproteins have also been suggested
Hyperlipidemia	Presumed associated turbidity
Heparin and alteplase-contaminated blood sampling	Heparin and alteplase solutions may contain phosphoric acid as a buffer solution
Hemolysis, rhabdomyolysis, tissue necrosis/infarction	Cellular extrusion of intracellular phosphorus with cell death. This is essentially true hyperphosphatemia