Falsely Elevated Estradiol Levels Due to Heterophile Antibody Interference: A Case Report and Literature Review.

Background: Immunoassay interference remains an important issue in clinical laboratory medicine, and false increases in estradiol levels due to detection interference are rare, but they cannot be ignored.

Case presentation: We herein report the case of a 41-year-old woman who underwent a series of extensive and superfluous medical examinations because of erroneous laboratory findings according to the Siemens Centaur serum estradiol assay due to heterophile antibody interference. Her estradiol levels were measured several times, which measured between 7534 and 9772 pg/mL. Heterophile antibody interference was identified through method comparisons, polyethylene glycol precipitation, a gradient dilution test, and the use of a heterophile-blocking reagent.

Conclusion: The rapid identification of interference in estradiol testing poses a challenge for laboratory staff; however, it is vital for preventing unnecessary medical treatment and reducing healthcare costs. Analytical interference should be suspected when clinical manifestations do not align with laboratory results. Consequently, clinicians and laboratory personnel need to develop an anti- interference workflow to mitigate such occurrences in the future.