Clinical Significance

Women being treated with fulvestrant will show an increase in estradiol concentrations with this assay. Subsequently, the incorrect level of estradiol may lead to misinterpretations of the hormone status, and the use of fulvestrant may be altered. In addition, the efficiency of anti-estrogen treatment might be underestimated. A medical risk for postmenopausal women under fulvestrant treatment cannot be excluded. Due to the risk of cross-reactivity, this estradiol assay should not be used when monitoring estradiol levels in patients being treated with fulvestrant. Alternative test: Mayo test code, EEST, the methodology by LC-MS/MS. No sample should be collected on patients receiving therapy with high biotin doses (i.e. biotin therapy for Multiple Sclerosis or oncology patients; skin, hair and nail supplements, or multivitamins containing > 5 mg/day) until at least 12 hours after the last biotin administration. If unsure, or if the clinical picture does not fit the results please contact the laboratory. We have methods to check for biotin interference as well as for any other interferences and for the accuracy of the results.

Biotin interference would falsely increase the result of this assay.