This test may exhibit interference when the sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.
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E2 levels in children, postmenopausal women, and men are much lower than in women of reproductive age. The increased sensitivity and specificity that are achieved by LC/MS-MS are the more appropriate choice for these clinical situations than the electrochemiluminescence immunoassay (ECLIA) method.1,2 See Estradiol, Sensitive, LC/MS [140244]. LC/MS-MS offers superior analytical sensitivity, specificity and a larger dynamic range than immunoassays.1 The clinical applications benefiting from highly sensitive E2 measurement include the assessment of congenital defects in sex steroid metabolism and disorders of puberty. This sensitive assay also has application in the evaluation of estrogen deficiency in men and menopausal women, fracture risk assessment in these populations, and increasingly, in therapeutic drug monitoring of low-dose female hormone replacement therapy or antiestrogen treatment.
Estradiol levels tend to fluctuate dramatically during the perimenopausal transition. There is significant overlap of the expected range in menopausal women with values observed during normal menstrual cycles. Estradiol results obtained with different assay methods cannot be used interchangeably in serial testing. To monitor a patient’s serial results, it is best to ensure that the same methodology is used each time the test is performed.
As with all test containing monoclonal mouse antibodies, erroneous findings may be obtained from samples taken from patients who have been treated with monoclonal mouse antibodies or who have received them for diagnostic purposes. In rare cases, interference due to extremely high titers of antibodies to streptavidin and ruthenium can occur. The test contains additives, which minimize these effects.
Due to the risk of cross-reactivity, this estradiol assay should not be used when monitoring estradiol levels in patients treated with fulvestrant (Faslodex®). An alternate method that is not subject to interference by this drug such as the Estradiol, Sensitive, LC/MS [140244] should be used to measure estradiol levels in patients treated with fulvestrant.
