Oestradiol

Chemical Pathology

Notes

Oestrogens in females are released primarily by the ovaries, being at their peak as follicles mature prior to ovulation. Small amounts are produced by the testes in men, and by the adrenal cortex in both sexes. During pregnancy oestrogens are produced by the placenta.

The main biologically active oestrogen is 17ß-oestradiol; this is the form assayed in this laboratory.

Approximately 98% of oestradiol is bound to transport proteins (mainly sex hormone binding globulin, SHBG) in the blood.

Serum oestradiol levels may be indicated in:

• Investigation of gynaecomastia in men
• Assessing ovarian status, including follicle development, for assisted reproduction protocols (e.g. in vitro fertilization)
• Investigation of precocious/delayed puberty, especially in females
• Checking for tachyphylaxis with oestrogen implants
• Checking for poor absorption with oestrogen skin patches
• Patients on the long term contraceptive method, Depo-Provera. Depo-Provera can lower oestrogen levels, however, bone scanning is the only evidence-based method for assessing risk of osteoporosis in these patients.
• Investigation of oestrogen-producing neoplasms, mainly in males.

Serum oestradiol levels are not useful for:

• Monitoring oral oestrogen replacement (non-oestradiol HRT preparations contain high concentrations of oestrogens which the assay does not detect; oral conjugated equine oestrogens are altered on first pass through the liver to an undetectable form)
• Assessing the menopausal state, as variable amounts of oestrogen are secreted in the perimenopausal period (i.e. one year before the menopause) and fertile cycles may follow even with very low oestradiol levels.

Sample requirements

• If the patient is on high dose biotin therapy (>5 mg/day), collect the sample at least 8 hours after the last dose.

For adults, blood taken into a 5mL gold top gel tube (or rust top for the Acute Unit)

For children, blood taken into a 3.5mL rust top gel tube

For neonates, blood taken into a 0.8mL minicollect lithium heparin tube

Storage/transport

Send at ambient temperature to the laboratory. Do not store.

Required information

Include relevant clinical details, including any medications or use of oestrogen (please specify preparation) or progestin (Depo-Provera) contraceptives or replacement therapies.

Turnaround times

• The turnaround time is 72 hours.
• Samples may be processed urgently to support fertility clinics at CGH. Please contact the laboratory to arrange this.
• If the assay is required for patients being treated at other fertility clinics, please contact the Duty Biochemist in advance to ensure an appropriate turnaround time.

Reference ranges

Oestradiol assayed by the Cobas Elecsys Estradiol III assay

For diagnostic purposes, the oestradiol results should always be assessed in conjunction with the patient's medical history, clinical examination and other findings.

Further information

To learn more about oestradiol, visit the oestrogen page at Lab Tests Online or for more information on IVF, visit NHS Choices

Page last updated: 31/01/2024