E2

E₂

Symbol for estradiol.

UBE2K

A gene on chromosome 4p14 that encodes a ubiquitin-conjugating enzyme which interacts with RING finger proteins. It ubiquitinates huntingtin, a protein linked to Huntington's disease, the known functions of which include a role in aggregate formation of polyglutamine proteins and apoptosis suppression in polyglutamine diseases, as well as a role in releasing newly synthesised MHC class-I heavy chains from the endoplasmic reticulum.

Estradiol

Synonym/acronym: E₂.

Common use

To assist in diagnosing female fertility problems that may occur from tumor or ovarian failure.

Specimen

Serum (1 mL) collected in a gold-, red-, or red/gray-top tube. Plasma (1 mL) collected in green-top (heparin) tube is also acceptable.

Normal findings

(Method: Immunoassay)

Age	Conventional Units	SI Units (Conventional Units × 3.67)
6 mo–10 yr
Male and female	Less than 15 pg/mL	Less than 55 pmol/L
11–15 yr
Male	Less than 40 pg/mL	Less than 147 pmol/L
Female	10–300 pg/mL	37–1,100 pmol/L
Adult male	10–50 pg/mL	37–184 pmol/L
Adult female
Early follicular phase	20–150 pg/mL	73–551 pmol/L
Late follicular phase	40–350 pg/mL	147–1,285 pmol/L
Midcycle peak	150–750 pg/mL	551–2,753 pmol/L
Luteal phase	30–450 pg/mL	110–1,652 pmol/L
Postmenopause	Less than 20 pg/mL	Less than 73 pmol/L

Description

Estrogens are steroid hormones named for their role in the female estrous cycle. Estrogens are responsible for the development of secondary female sex characteristics (development of breasts, appearance of pubic hair), maintenance of the menstrual cycle, maintenance of the placenta during pregnancy, and initiation of lactation (via a feedback loop involving prolactin). The three types of estrogen commonly measured are estrone (E1), estradiol (E2), and estriol (E3). Estrogens are produced by the ovaries, liver, adrenal glands, and in fatty tissue (e.g. breast tissue). Ovarian estrogen hormone formation begins with the conversion of cholesterol into androstendione in the theca interna cells, followed by conversion to estradiol in ovarian granulosa cells. Estradiol, the most powerful of the estrogens, is the main estrogen produced in women who are not pregnant during the period between puberty and menopause. Estriol is the primary estrogen secreted during pregnancy and it is provided by the placenta. Secretion of estrogens is influenced by the pituitary gonadotropins, follicle stimulating hormone (FSH) and luteinizing hormone (LH). After menopause the ovaries stop producing estrogens and the secondary sources (liver, adrenal glands, and breast tissue) provide estrogens mostly in the form of estrone..

This procedure is contraindicated for

N/A

Indications

Assist in determining the presence of gonadal dysfunction
Evaluate menstrual abnormalities, fertility problems, estrogen-producing tumors in women, and testicular or adrenal tumors and feminization disorders in men
Monitor menotropins (Pergonal) therapy; menotropins is a preparation of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) used to induce ovulation and increase the chance of pregnancy

Potential diagnosis

Increased in

Adrenal tumors (related to overproduction by tumor cells)
Estrogen-producing tumors
Feminization in children (related to increased production)
Gynecomastia (newborns may demonstrate swelling of breast tissue in response to maternal estrogens; somewhat common and transient in pubescent males)
Hepatic cirrhosis (accumulation occurs due to lack of liver function)
Hyperthyroidism (related to primary increases in estrogen or response to increased levels of sex hormone–binding globulin)

Decreased in

(resulting in lack of estrogen synthesis)

(related to lack of estrogen synthesis)

(genetic abnormality in females in which there is only one X chromosome, resulting in varying degrees of underdeveloped sexual characteristics)

Critical findings

N/A

Interfering factors

Drugs that may increase estradiol levels include cimetidine, clomiphene, dehydroepiandrosterone, diazepam, estrogen/progestin therapy, ketoconazole, mifepristone (some patients with meningiomas and not receiving any other drugs), nafarelin, nilutamide, phenytoin, tamoxifen, and troleandomycin.
Drugs that may decrease estradiol levels include aminoglutethimide, chemotherapy drugs, cimetidine, danazol, fadrozole, formestane, goserelin, leuprolide, megestrol, mepartricin, mifepristone (pregnant women with expulsion of fetus), nafarelin (women being treated for endometriosis), and oral contraceptives.
Estradiol is secreted in a biphasic pattern during normal menstruation. Knowledge of the phase of the menstrual cycle may assist interpretation of estradiol levels.

Nursing Implications and Procedure

Pretest

Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
Patient Teaching: Inform the patient this test can assist in assessing hormone level.
Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
Obtain a history of the patient’s endocrine and reproductive systems, as well as phase of menstrual cycle, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
Record the date of the last menstrual period and determine the possibility of pregnancy in perimenopausal women.
Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and neutraceuticals (see Effects of Natural Products on Laboratory Values). Note the last time and dose of medication taken.
Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
Note that there are no food, fluid, or medication restrictions unless by medical direction.

Intratest

Potential complications: N/A
Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
Promptly transport the specimen to the laboratory for processing and analysis.

Post-Test

Inform the patient that a report of the results will be made available to the requesting health-care provider (HCP), who will discuss the results with the patient.
Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Explain to the patient the importance of following the medication regimen and instructions regarding drug interactions. Answer any questions or address any concerns voiced by the patient or family.
Instruct the patient to be prepared to provide the pharmacist with a list of other medications he or she is already taking in the event that the requesting HCP prescribes a medication.
Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

Related tests include AFP, CEA and cancer antigens, CT pelvis, FSH, LH, MRI pelvis, progesterone, prolactin, and US pelvis.
Refer to the Endocrine and Reproductive systems tables at the end of the book for related tests by body system.