Spurious hypophosphatemia associated with multiple myeloma.
OBJECTIVE
To report on the phenomenon of spurious hypophosphatemia associated with multiple myeloma.


METHODS
A case report is presented, and the pertinent published literature is reviewed. The mechanisms by which multiple myeloma can cause both true and false hypophosphatemia are discussed, as are methods by which the important distinction between these conditions can be made.


RESULTS
At the time of surgical treatment of a hip fracture, an 80-year-old man with a history of multiple myeloma was found to have hypophosphatemia. Despite intravenous administration of large amounts of phosphate, the low phosphate values persisted. Only when a blood sample was submitted to another laboratory that used a different technique for determining phosphate was a normal phosphate level reported.


CONCLUSIONS
In patients with multiple myeloma, the myeloma protein can cause biochemical interference with certain phosphate assays, which could lead to false results. This phenomenon should be considered in such patients in order to avoid inappropriate and potentially dangerous phosphate replacement therapy.
Caras
J A
JA
Division of Endocrinology, Clinics of North Texas, Wichita Falls, Texas 76302, USA.