Diagnostic Use
Assessment of ovarian function, including the response in infertile women to treatment with clomiphene, gonadotrophins, or gonadotrophin releasing hormone.
Investigation of precocious puberty in female children.
To confirm menopausal status in women (in conjunction with LH and FSH ).
Investigation of gynaecomastia in males.
In men, oestradiol levels <60 pmol/L are associated with increased fracture risk (ref: J Clin Endo Metab 2010; 95(1):3-10)
Interference with Oestradiol Method by Chemotherapy Drug Fulvestrant (Faslodex).
Fulvestrant is an oestrogen receptor blocking drug used in treatment of breast cancer with close structural similarity to oestradiol . This drug has been found to cause marked interference in the immunoassay used at LabPlus (Roche Cobas).
Similar interference has also been identified in other oestradiol immunoassays used in Auckland. The degree of interference varies by oestradiol concentration, so no factor or baseline can be applied.
Fulvestrant is not currently funded by Pharmac. It is available under Section 29 but is currently seldom used in New Zealand. In the unlikely event that a patient may be taking this drug please be aware of this interference.
If you wish to discuss further please contact a Chemical Pathologist via the contact information below.
Interference with many Immunoassays by Biotin.
Most immunoassays (e.g. TSH, fT4, ferritin) used at LabPlus incorporate biotin into the formulation of the assay. The potential for significant interference in these assays has been identified in patients taking large doses of biotin (at least 10-50mg/day). The interference can either cause false elevation or false reduction depending on the assay.
Very small doses commonly used in multivitamins do not have any significant effect. Because of the short half-life of biotin in plasma (about 1-2 hrs) separation from dosing by at least 8hr is also recommended .
If you wish to discuss further please contact a Chemical Pathologist via the contact information below.
Test Method
Principle: Competitive type immunoassay with chemiluminescence detection
Reagents: Roche Estradiol III
Analyser: Cobas e801
Limitations / Interference
Interference with many Immunoassays by Biotin.
Most immunoassays (e.g. TSH, fT4, ferritin) used at LabPlus incorporate biotin into the formulation of the assay. The potential for significant interference in these assays has been identified in patients taking large doses of biotin (at least 10-50mg/day). The interference can either cause false elevation or false reduction depending on the assay.
Very small doses commonly used in multivitamins do not have any significant effect. Because of the short half-life of biotin in plasma (about 1-2 hrs) separation from dosing by at least 8hr is also recommended .
If you wish to discuss further please contact a Chemical Pathologist via the contact information below.
Uncertainty of Measurement
7% below level of 350 pmol/L
5% above level of 750 pmol/L