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Abstract: SA-PO311

Pseudo-Hyperphosphatemia: A Diagnostic Conundrum

Session Information

Category: Bone and Mineral Metabolism

  • 502 Bone and Mineral Metabolism: Clinical

Authors

  • Lathiya, Maulik, Mayo Clinic Health System North West Wisconsin, Eau Claire, Wisconsin, United States
  • Errabelli, Praveen K., Mayo Clinic Health System North West Wisconsin, Eau Claire, Wisconsin, United States
  • Khan, Abdul M., Mayo Clinic Health System North West Wisconsin, Eau Claire, Wisconsin, United States
  • Jimenez Lopez, Jaime R., Mayo Clinic Health System North West Wisconsin, Eau Claire, Wisconsin, United States
  • Singh, Devender, Mayo Clinic Health System North West Wisconsin, Eau Claire, Wisconsin, United States
Introduction

Hyperphosphatemia is commonly seen in patient with chronic kidney disease however there are rare clinical situations where it can be seen in patients with normal renal function when interpretation of serum phosphate levels can be challenging due to potential analytical limitations. We present a case report demonstrating the diagnostic challenge of pseudo hyperphosphatemia to highlight the importance of high suspicion of spuriously elevated phosphate level.

Case Description

This is a 54-year-old female with history of multiple myeloma and diagnosed 1 year ago presented with fever and confusionI. In the ER and she was noted to have severe anemia and thrombocytopenia. In addition she was noted to have phosphorus level of 19.2 mg/dL with plasma creatinine was 0.55 mg/dL. Despite aggressive hydration and diuresis repeated measurement of phosphate levels showed persistent elevation and highest phosphate level being 25.7 mg/dL.
After excluding common causes of hyperphosphatemia and noted resistance to treatment a diagnosis for spuriously pseudo hyperphosphatemia was made. This was attributed to analytic interference of elevated paraprotein level.

Discussion

True Hyperphosphatemia with normal renal function is a rarely reported condition. Clinicians should have a high suspicion for pseudo hyperphosphatemia/ spurious hyperphopahtemia due to analytical limitations to avoid expensive diagnostic work up, treatment and prologned hospital stay.