Estradiol (E2)

Alternative Names
  • 17- Beta Estradiol
  • Enhanced Estradiol
  • Extracted Estradiol
  • E2

Test Code: 4010

CPT: 82670
Tests Included E2
Use Most circulating estradiol is bound to protein. It is estimated that only 1-3% of estradiol is free (unbound). In non-pregnant women, estradiol is secreted by the ovary and the corpus luteum. Levels of estradiol are used to monitor ovulatory status. Because estradiol levels reflect follicular maturation, the measurement of estradiol as cited in the scienti c literature has been used as a valuable tool in the assessment of sexual development, etiology of amenorrhea, causes of infertility and menopause.1,2

The adrenals and testes (in men) are also believed to secrete minute amounts of estradiol.3 Estradiol plays an important role in secondary hypogonadism as it has negative feedback on gonadotropin release. In this form of secondary hypogonadism testosterone will continue to decrease while estradiol increases. As this continues (becomes chronic) the ratio of free testosterone to estradiol can reach a critical point where estrogen suppression of gonadotropins predominates and may become irreversible; i.e., lead to permanently inhibited testosterone.4
Clinical Utility Estradiol levels are lowest at menses and into the early follicular phase and rise in the late follicular phase to a peak just prior to the hLH (human Luteinizing Hormone) surge, initiating ovulation. As the hLH peaks, the levels of estradiol decrease before rising again in the luteal phase. Endometrial growth is stimulated by estradiol and progesterone (secreted by the corpus luteum) in preparation for implantation of a fertilized egg. If conception does not occur, the secretion of estradiol and progesterone by the corpus luteum decreases, initiating menses.5

Abnormally high levels in males are indicative of feminizing syndromes such as gynecomastia.6
Intended Patient Population 18+ and Older Adult Males & Females
Patient Preparation None Specified
Sample Serum, Plasma
Tube Red, Green, Tiger
Volume 4mL Whole Blood (1mL Serum)
Min Sample Volume 0.5 mLs
Reference Ranges M ≥ 18 yrs old; 0-47 pg/mL
F  Mid-Follicular ≥ 18 yrs old; 27-122 pg/mL
F  Mid-Luteal ≥ 18 yrs old; 49-291 pg/mL
F  Peri-Ovulatory ≥ 18 yrs old; 95-433 pg/mL
F  Post-Menopausal ≥ 18 yrs old; 0-40 pg/mL
Analytical Measurement Range 20 -4800 pg/mL
Units pg/mL
Test Methodology Chemiluminescent Immunoassay
Test Turnaround Time 7 Days
Limitations Estradiol values from pregnant females may be affected by high levels of estriol such as are present in the second
and third trimesters of pregnancy.7 Control materials or survey samples containing high levels of estriol may be
similarly affected.
Shipping Requirements Refrigerated
Specimen Stability 7 Days RT
5 Days RF
Reject Criteria Gross Lipemia
Laboratory Developed Test (LDT) Yes
CMS Guidance None
  1. Carr, B R , Disorders of the ovary and female reproductive tract. In Williams Textbook of Endocrinology, 8th edition. Edited by Wilson, J D and Foster, D W Philadelphia, PA: W B Saunders Co., 733-798, 1992.
  2. Hall, J E Polycystic ovarian disease as a neuroendocrine disorder of the female reproductive axis. In Endocrinology and Metabolism Clinics of North America, Neuroendocrinology II. Edited by Veldhuis, J D Philadelphia, PA: W B Saunders Co., 75-92.
  3. C A and Ashwood, Tietz Textbook of Clinical Chemistry, 2nd Edition. 1994. Edited by Burtis, E R Philadelphia, PA: W B Saunders Co., 1857-1863.
  4. The role of estradiol in the maintenance of secondary hypogonadism in males in erectile dysfunction. Cohen PG, Med Hypotheses, 1998 Apr;50(4):331-3.
  5. Yen, S S C , The Human Menstrual Cycle- Neuroendocrine regulation. In Reproductive Endocrinology. Edited by Yen, S S C and Jaffe, R B Philadelphia, PA: W B Saunders Co., 273-308, 1991.
  6. Reyes-Fuentes, A. and Veldhuis, J D 1993. Neuroendocrine physiology of the normal male gonadal axis. In Endocrinology and Metabolism Clinics of North America. Edited by Velduis, J D Philadelphia, PA: W.B. Saunders Co., 22:93-124.
  7. Williams, Textbook of Endocrinology, 8th edition. Edited by Wilson, J D and Foster, D W Philadelphia, PA: W B Saunders Co., 978 - 995, 1992.

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