Estradiol

DESCRIPTION:
Estradiol 17 beta is the most important natural estrogen of the ovaries and placenta, it is responsible for the development of secondary sexual characteristics of a woman, normal menstruation and for the preparation of the uterus for the implantation of a fertilized egg. Estrogen concentrations are very low in children and after menopause. Estradiol is the most biologically active estrogen and originates from the ovaries, testicles and placenta. Estradiol (E2) is the main hormone in women secreted by the ovarian follicle and is a sign of its growth and maturation. Like FSH, estradiol (E2) can be measured on day 3 of the menstrual cycle. During pregnancy, estradiol is secreted by the placenta. Estradiol enters the bloodstream where 1-3% is free, 40% is bound to SHBG (sex-hormone binding globulin) and the rest is bound to albumins. The main role of estradiol is its action in the menstrual cycle.

DETERMINATION:
Determination method: ECLIA. Sample: serum or plasma (EDTA, heparin). The stability of the sample is 2 days at 2-8°C, 6 months at -20°C.

CLINICAL SIGNIFICANCE:
Measuring the level of estradiol in circulation is important for determining ovarian function and monitoring follicle development. Serum estradiol (E2) values ​​are used to assess gonadal dysfunction as well as prepubertal feminization, primary amenorrhea, ovulation and to assess estrogen secreted from tumors in men. In patients with secondary amenorrhea, 2 categories can be separated based on the level of E2. Patients with amenorrhea accompanied by hirsutism, obesity and polycystic ovaries usually have a normal E2 concentration in the follicular phase. Patients with pathological changes (abnormalities) of the hypothalamus or pituitary gland have a low level of E2. A low estradiol level below 55 pmol/L usually indicates ovarian failure. An elevated value of estradiol in children under 12 years of age can be a signal of premature puberty. In normal, non-pregnant women, estradiol is secreted mainly by the theca and granulosa cells of the developed follicle and corpus luteum. A very low level of estradiol is found in abnormally shaped ovaries and menopause.

An elevated E2 value is associated with tumors. 1) Physiological changes in the concentration of estradiol in the serum In the follicular phase, FSH stimulates the development of follicles in the ovary and, together with LH, promotes (stimulates) the secretion of estrogen. The concentration of estrogen is initially low and slowly increases, reaching maximum values ​​shortly before ovulation. At the same time, there is a slight decrease in FSH concentration. When the concentration of estrogen reaches its maximum value, there is a short-term but sudden increase in the concentration of LH. Along with the increase in LH concentration, there is also a smaller increase in FSH concentration, after which ovulation occurs. In the luteal phase, there is an increased excretion of progesterone, the increase of which is accompanied by an increase in estrogen from the corpus luteum. If pregnancy does not occur, the yellow body (corpus luteum) decays in 10 to 12 days. The concentration of progesterone and estrogen decreases and menstruation occurs. If the egg is fertilized, the egg implants in the endometrium, the concentration of estrogen and progesterone continues to increase, and FSH decreases. At the same time, there is an increase in hCG. Laboratory results must always be interpreted in relation to the phase of the menstrual cycle. 2) Pathological changes in the concentration of estradiol in the serum A)

Increased values of serum estradiol concentration in: Alcoholism / Biliary liver cirrhosis, unspecified / Benign ovarian neoplasms / Other pituitary gland disorders / Endometriosis, unspecified / Heart failure; cardiac arrest / Insulin-dependent diabetes mellitus (IDDM) / Klinefelter’s syndrome karyotype 47, XXY / Laennec’s or alcoholic cirrhosis / Other testicular disorders / Premature puberty / Thyrotoxicosis (hyperthyroidism) / Malignant neoplasms of the ovaries (Ovarian cancer) / Malignant neoplasms of the body of the uterus (Endometrium) B) Reduced values of estradiol concentration in serum in: Anorexia nervosa / Hypopituitarism / Polycystic ovarian diseases / Pre-eclamptic toxemia; preeclampsia

RESULT:
The reference interval depends on gender, age and the method of determination. The reference interval is displayed with each validated result.