An estrogen test measures the level of the most important estrogen hormones (estradiol, estriol, and estrone) in a blood, saliva or urine sample.
Estradiol is the most commonly measured type of estrogen for nonpregnant women. The amount of estradiol in a woman's blood varies throughout her menstrual cycle. So timing of the test is important in premenopausal women. After menopause, estradiol production drops to a low but constant level.
Estriol levels are usually measured during pregnancy. It is produced in large amounts by the placenta, the tissue that links the fetus to the mother. Estriol can be detected as early as the 9th week of pregnancy, and its levels increase until delivery.
All three of these are often measured by Holistic doctors, and a compounding pharmacy can prepare a customized blend of the three to help restore any imbalance.