If these particular estradiol assays are used for this group of post-menopausal women, falsely elevated estradiol results could lead to misinterpretation of the menopausal status of these women. This may result in treatment with fulvestrant being altered.
Laboratory staff are advised to determine if estradiol immunoassays are used in their laboratory, and to continue to use affected estradiol immunoassays for patients not on fulvestrant. In patients on the drug, they should consider alternative methods, such as liquid chromatography-mass spectrometry. There may be a need to carry out a review of previously reported test results. Healthcare personnel managing patients on this drug are advised that when test requests include estradiol, they should state if the patient is on fulvestrant. They should also consider reassessing the menopausal status of patients on fulvestrant by other means where necessary.