Background: Abemaciclib is a CDK4/6 inhibitor used in breast cancer treatment alongside endocrine therapy. Positive interference in the Abbott Alinity (AA) oestradiol assay in premenopausal woman receiving abemaciclib, despite ovarian function suppression, was shown using liquid chromatography-mass spectrometry (LC-MS/MS). 1,2 We investigated a patient with abemaciclib interference using several oestradiol assays.
Chan et al. (Sun,) studied this question.