Sex Hormones Tests

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Sex hormones tests

Definition

Sex hormones tests include tests that measure levels of estrogen (estradiol and estriol), progesterone, and testosterone (total and free).

Purpose

In non-pregnant women, a test of estradiol (E2) levels is ordered to evaluate delayed sexual maturity, precocious puberty , menstrual problems, and infertility , and ovarian failure. It is also used to test for tumors in both males and females that secrete estrogen. The test is also used to measure estrogen secretion in males who present with gynecomastia and feminization in male children.

Estriol (E3), another estrogen, is only ordered for pregnant women (typically at 15–18 weeks gestation). The test is used as part of the triple marker screen (in association with alpha fetoprotein and chorionic gonadotropin) for Down syndrome .

A progesterone test is ordered to evaluate women for anovulation, and to investigate precocious puberty. Progesterone may be measured in those persons with ovarian or adrenal cancer that secrete progesterone.

The testosterone test (free testosterone and/or total testosterone) is used to evaluate delayed sexual development, male sexual precocity, testicular failure, virilism in females, infertility, and tumors that secrete testosterone.

Precautions

Both the estrogen and testosterone test are most often measured by radioimmunosasay and results can be affected by radioactive scans. When RIA is used the estradiol or estriol tests should not be performed on a patient who has received radioactive dye within 48 hours prior to the test. For RIA testosterone tests, the period between the scan and the test should be at least seven days. Oral contraceptives may interfere with progesterone and estradiol results. Tetracycline, some phenothiazines, diazepam, clomiphene, and some vitamins may interfere with estradiol results.

Estradiol and progesterone results vary with the phase of the menstrual cycle, and this must be taken into account when interpreting the results of these tests.

Sex hormone tests are performed on blood collected by venipuncture. The nurse or phlebotomist performing the procedure should observe universal precautions for the prevention of transmission of bloodborne pathogens.

Description

The sex hormones control the development of primary and secondary sexual characteristics and regulate the sex-related functions of the body, such as the menstrual cycle, and the production of eggs or sperm. Because of their normally low concentration in plasma the sex hormones are typically measured by radioimmunoassay (RIA), chemiluminescence immunoassay, or fluorescent immunoassay.

Estradiol

While there have been more than 30 of these hormones identified, only estradiol (E2) is necessary to evaluate ovarian function. Estradiol is the most potent of the estrogens, but it accounts for only one-third of the total estrogen in premenopausal females. In the nonpregnant female the ovaries are responsible for almost all estradiol production. In pregnancy , some estradiol is also produced by the placenta. Estradiol is produced from cholesterol, androstenedione, and testosterone. In males, estradiol is mainly produced from testosterone by the testes, but a small amount is also made by the adrenal cortex.

In menopause , the ovaries stop producing estradiol and estrone (E1) becomes the principal estrogen. A small amount of estradiol is formed from adrenal conversion of androstenedione, but this accounts for only about 15% of total estrogens. Plasma estradiol will be low in menopause, and FSH and LH will usually be increased. The measurement of estrone is seldom needed, but may be used to investigate vaginal bleeding after menopause or when estrone secreting ectopic hormone production is suspected.

Prior to menopause, estradiol is most often measured to evaluate amenorrhea and ovarian failure. In primary ovarian failure the ovaries may either fail to develop (as in Turner syndrome) or fail to produce estrogens as a result of autoimmune, metabolic, or endocrine disease. The plasma estradiol will be low, but the plasma levels of both LH and FSH are elevated. If secondary sexual characteristics are undeveloped, and the person is of short stature, chromosomal studies may reveal Turner syndrome as the cause. Primary amenorrhea results in failure to have a menses by age 16. In addition to ovarian failure, primary amenorrhea may be caused by endometriosis, polycystic ovary syndrome, anatomic defects in the vagina or uterus, and other disorders. In secondary ovarian failure, amenorrhea may be caused by pituitary failure or prolactinoma. In the former, both plasma and urinary LH and FSH will be low. In prolactinoma, LH and FSH are low because their release is suppressed by excessive secretion of prolactin which inhibits corticotropin releasing hormone.

An increased plasma level of estrogen indicates ovarian hyperfunction which may occur as a result of an ovarian tumor such as a granulosa-thecal cell tumor or signals the presence of an ectopic estradiol-producing tumor.

Estradiol is also measured to evaluate the response of patients to progesterone challenge and to determine responsiveness to clomiphene. In a person with amenorrhea, estradiol greater than 40 pg/mL following progestin administration excludes estrogen deficiency as a cause of amenorrhea. Clomiphene blocks the hypothalamic response to estrogen and is a treatment for patients with anovulation who have adequate estrogen and normal pituitary function. Use of the drug requires demonstration that the ovaries can produce estradiol.

Estriol (E3)

Estriol (E3) is the principal estrogen produced during pregnancy. Estriol is produced by the placenta from dehydroepiandosterone sulfate derived from the fetal liver and adrenals. Estriol levels are low by approximately 25% (less than 75 MOM) in Down syndrome and other trisomies. Tests on maternal plasma for alpha-fetoprotein, chorionic gonadotropin, and unconjugated estriol are perfomed at 15–18 weeks gestation. Measurement of unconjugated estriol (uE3) is a better reflection of fetal-derived estriol than is total estriol, and is measured by RIA. Estriol levels are also low for the gestational age in spontaneous abortions and in threatened pregnancy, but are no longer needed for the diagnosis of these conditions.

Progesterone

Progesterone in the nonpregnant female is produced mainly by the ovaries with a small fraction also made by the adrenals. Progesterone levels in plasma are very low prior to ovulation. At ovulation, the level begins to rise due to secretion by the corpus luteum. The progesterone level peaks in the middle of the luteal phase (about one week prior to the next menses). Progesterone causes thickening of the endometrium in order to prepare the ovum for implantation should it be fertilized. In the absence of fertilization, negative feedback of progesterone on the hypothalamus results in suppression of luteinizing hormone and the corpus luteum involutes causing the wall of the uterus to breakdown. If fertilization occurs, the corpus luteum and placenta produce large amounts of progesterone. The most common use of plasma progesterone measurement is to evaluate ovulation. Progesterone is often measured on days 21 and 22 of the menstrual cycle. At this point the progesterone should represent the midluteal peak and levels above 5 ng/L are considered evidence of ovulation. Lower levels indicate a disruption of the normal luteal phase of progesterone production.

Testosterone

In males testosterone is produced by the testes under the control of luteinizing hormone. It is responsible for development of the testes, secondary sexual characteristics, and spermatogenesis. Testosterone is subject to diurnal variation in response to LH and highest plasma levels occur at 6–9 a.m. Approximately 60% of plasma testosterone is bound to sex hormone binding globulin (SHBG) and almost 40% is bound to albumin. Only about 2% of the hormone is in the free form and is physiologically active. Measurement of free hormone levels is more sensitive than total hormone because small changes in SHBG concentration can increase free hormone levels. A reduction in binding of testosterone to SHBG can be caused by drugs or other steroid hormones, and will increase free hormone levels. In males, plasma testosterone is low in hypogonadism and is measured in male children with delayed or absent sexual maturation. Primary testicular failure may result from Klinefelter syndrome, testicular infection , injury, and other causes. In these cases the plasma testosterone is low, but the LH and FSH are increased. In secondary testicular failure, plasma testosterone, FSH, and LH are decreased. Testosterone levels are also useful for the differential diagnosis of gynecomastia. In addition to low testosterone, gynecomastia can be caused by drugs that interfere with testosterone action, or ectopic tumors that secrete estrogen or chorionic gonadotropin.

Testosterone levels may be measured in both males and females to identify tumors that secrete the hormone. Testosterone is produced by some testicular and ovarian tumors as well as some others. Overproduction of testosterone caused by testicular, adrenal, or pituitary tumors in the young male may result in precocious puberty. Overproduction in females caused by an ovarian tumor or adrenal adenoma causes virilization and hursitism (excessive hair growth). In cases of ambiguous sex or virilization in female children, testosterone and adrenal androgens such as androstenedione may be measured. Most cases of congenital adrenal hyperplasia are caused by 21-hydroxylase deficiency which is associated with excessive androgen production. The enzyme deficiency blocks cortisol synthesis and causes intermediate steroids to accumulate that are converted to testosterone and other androgens. Androgens are most often measured by RIA or gas chromatography-mass spectroscopy (GC-MS).

Preparation

Progesterone and testosterone tests require a blood sample; it is not necessary for the patient to restrict food or fluids before the test. However, testosterone specimens should be drawn in the morning, because testosterone levels are highest in the early morning hours. For progesterone tests, the date of the patient's last menstrual cycle or week of gestation should be noted on the test request slip.

The estrogen test can be performed on blood and/or urine. It is not necessary for the patient to restrict food or fluids for either test. If a 24-hour urine test has been requested, the patient should be instructed to discard the first morning specimen, then save all urine voided during the next 24 hours. The blood sample should be placed on ice immediately after it is drawn. It is also important to note the patient's sex, age, and menstrual cycle phase on the test request slip.

Aftercare

Discomfort or bruising may occur at the puncture site. Applying pressure to the puncture site until the bleeding stops helps to reduce bruising; warm packs relieve discomfort. Some people feel dizzy or faint after blood has been drawn and should be treated accordingly.

Complications

Other than potential bruising at the puncture site, and/or dizziness, there are no complications associated with these tests.

KEY TERMS

Amenorrhea —Cessation of the menstrual cycle.

Gynecomastia —Excessive development of the male mammary glands, even to the functional state.

Hirsutism —Abnormal hairiness, especially in women.

Hypogonadism —Underactivity of the testes.

Orchiectomy —Removal of one or both testes.

Spermatogenesis —The production of sperm.

Virilism —The presence of male characteristics in women.

Results

Normal values for sex hormone tests are highly dependent upon age and sex and in females the time of the collection relative to the menstrual cycle. Ranges vary from laboratory to laboratory depending upon the method used. Representative values for some patient groups are shown below.

Estradiol: For adult women, estradiol levels range from 20–150 pg/mL during the follicular phase, 100–500 pg/mL during the mid-cycle phase, and 50–150 pg/mL during the luteal phase. Menopausal women have estradiol levels of less than 18 pg/mL. The normal range for adult males is approximately 18–75 pg/mL.

Increased levels of estrogen are found in the following conditions:

ovarian tumor
adrenocortical tumor
some testicular tumors
pregnancy

Decreased levels of estrogen are found in the following conditions:

ovarian dysfunction
interuterine death in pregnancy
anorexia nervosa
primary and secondary hypogonadism
turner syndrome
infantilism
menopausal and post-menopausal symptoms
pituitary insufficiency
psychogenic stress

Progesterone levels for women during the follicular phase normally range from 0.1–1.5 ng/mL and 2–24 ng/mL during the luteal phase. The normal range for the mid-luteal peak is 4.5–25.5 ng/mL. For post meanopausal women, results fall below 1.0 ng/mL. Results for pregnant women are as follows:

first trimester: 9–50 ng/mL
second trimester: 18–150 ng/mL
third trimester: 60–260 ng/mL

For men, the normal progesterone value is 0.1–0.3 ng/mL. For children, normal values run from 7–51 ng/mL.

Increased levels of progesterone are seen:

during ovulation and pregnancy
with certain types of ovarian cysts
with a tumor of the ovary known as a choriocarcinoma

Decreased levels of progesterone are seen:

in toxemia of pregnancy
with a threatened abortion
during placental failure
after fetal death
with amenorrhea
due to gonadal dysfunction

Normal ranges for testosterone are generally 300–1,200 ng/dL for men, and 30–95 ng/dL for women. Boys between the ages of six and nine have normal values in the range of 3–30 ng/dL, while for girls of the same age the range is 2–20 ng/dL.

In men, increased levels are found in:

sexual precocity
adrenal hyperplasia
testicular tumor
hyperthyroidism
testicular feminization

In men, decreased levels are found in:

Klinefelter syndrome
primary and secondary hypogonadism
Down syndrome
orchiectomy
impotence
gynecomastia

In women, increased levels of testosterone are most commonly associated with ovarian and adrenal tumors and hirsutism.

Health care team roles

Physicians order sex hormone tests and interpret the results often with the assistance of endocrinologists. A nurse or phlebotomist collect the blood samples. Testing is performed by clinical laboratory scientists/medical technologists.