Estimation of haemoglobin concentrations using spectrophotometric tests

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.