A spurious markedly increased serum estradiol level due to an IgA lambda

To alert physicians about the potential for erroneous laboratory determinations of hormone levels and emphasize the need to assess the overall clinical situation as well. We present a case report of a woman with a dramatically increased serum estradiol (E(2)) level on radioimmunoassay and review the studies that led to the conclusion that this laboratory finding did not reflect her true estrogen status. In a 41-year-old woman, an unnecessary surgical procedure was performed because of a falsely increased serum E(2) level and a unilateral ovarian mass. The markedly increased serum E(2) measured by radioimmunoassay was found to be attributable to an IgA lambda that bound to the 125 I-labeled tracer of the assay. When repeatedly abnormal hormone levels and the clinical picture seem discrepant, use of a different assay method should be considered.