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oai:recercat.cat:2445/2228392026-03-05T19:09:16Zcom_2072_1057col_2072_478858col_2072_478916col_2072_478917

Analytical Interference of Exemestane With Androstenedione Immunoassays Giralt, Marina Ferrer, Roser Díaz Troyano, Noelia Vega, Belén Luque Ramírez, Manuel Martínez, Sílvia Fernández, Bárbara Martínez Serrano, Irene Fabregat, Aleix Urgell, Eulàlia Cardona, Ignasi Casals, Gregori Escobar Morreale, Héctor F. Farmacovigilància Radioimmunoassaig Drug monitoring Radioimmunoassay Background: Exemestane, an aromatase inhibitor commonly used for breast cancer treat- ment, shares structural similarities with sex steroids analyzed in clinical laboratories. We aimed to investigate the influence of exemestane cross-reactivity in the measurement of sex steroids across various immunoassays. Methods: We conducted a multicenter study involving measurements of androstenedione, testosterone, estradiol, progesterone , 17-hydroxyprogesterone in serum samples from women undergoing exemestane therapy (N =15; 25 mg/day). Measurements were per- formed using liquid chromatography-mass spectrometry (LC-MS) , various commercially available chemiluminescence immunoassays, ELISA, and radioimmunoassay. In-vitro cross-reactivity was assessed by adding exemestane and 17-hydroexemestane to serum samples. Results: Patients undergoing exemestane therapy had markedly falsely elevated andro- stenedione results in all immunoassays evaluated (N = 4), which correlated with serum ex- emestane levels. In-vitro experiments confirmed this interference to be caused by cross-re- activity with exemestane. Additionally, one immunoassay yielded falsely elevated estradiol results in 20% of patients. However, in-vitro experiments did not confirm this to be caused by cross-reactivity with exemestane or 17-hydroexemestane. Conclusions: Exemestane cross-reacts with androstenedione immunoassays, causing falsely elevated results in treated patients. This analytical interference may raise unneces- sary concerns, leading to expensive diagnostic workups. 2025-08-29T11:28:50Z 2025-08-29T11:28:50Z 2025-03-21 2025-08-26T10:01:23Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2234-3814 https://hdl.handle.net/2445/222839 40114653 eng Reproducció del document publicat a: https://doi.org/10.3343/alm.2024.0362 Annals of Laboratory Medicine, 2025, vol. 45, num. 4, p. 410-419 https://doi.org/10.3343/alm.2024.0362 cc by-nc-nd (c) Giralt, Marina et al, 2025 http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/openAccess 10 p. application/pdf Annals of Laboratory Medicine Articles publicats en revistes (Institut d'lnvestigació Biomèdica de Bellvitge (IDIBELL))