Preparation
Estradiol (E2) is the primary female sex hormone — the driver of the menstrual cycle, fertility, bone strength and mood. Measuring it in blood gives fertility specialists and gynaecologists a direct read on ovarian function at exactly the moment it matters.
The test is a pillar of fertility workups and treatments: baseline E2 on cycle day 2–3, monitoring follicle development during stimulation cycles, and investigating irregular periods, absent cycles or early menopause concerns. It is also part of hormone assessment in men and children in specific clinical situations — always interpreted by the treating specialist.
Timing is everything with E2: the meaningful value depends on which day of your cycle the sample is drawn, so book the day your doctor specifies. The draw takes minutes at your home; the report reaches your app the same or next day for your specialist to read against your cycle.
For a baseline reading, day 2 or 3 of the cycle is standard. For follicle monitoring, your fertility doctor specifies the exact days — book the day they advise, as timing changes the meaning entirely.