LH response to GnRH blood test
LH response to GnRH is a blood test to help determine if your pituitary gland can correctly respond to gonadotropin releasing hormone (GnRH). LH stands for luteinizing hormone.
How the Test is Performed
A blood sample is taken, and then you are given a shot of GnRH. After a specified time, more blood samples are taken so that LH can be measured.
Blood sample is taken
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
Read Article Now Book Mark ArticleLH
The LH blood test measures the amount of luteinizing hormone (LH) in blood. LH is a hormone released by the pituitary gland, located on the undersid...
Read Article Now Book Mark ArticleHow to Prepare for the Test
No special preparation is necessary.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed
GnRH is a hormone made by the hypothalamus gland. LH is made by the pituitary gland. GnRH causes (stimulates) the pituitary gland to release LH.
This test is used to tell the difference between primary and secondary hypogonadism. Hypogonadism is a condition in which the sex glands make little or no hormones. In men, the sex glands (gonads) are the testes. In women, the sex glands are the ovaries.
Hypogonadism
Hypogonadism occurs when the body's sex glands (gonads) produce little or no hormones. In men, these glands are the testes. In women, these glands ...
Read Article Now Book Mark ArticleDepending on the type of hypogonadism:
- Primary hypogonadism starts in the testicle or ovary
- Secondary hypogonadism starts in the hypothalamus or pituitary gland
This test may also be done to check for the reason why there is a:
- Low testosterone level in men
Testosterone
A testosterone test measures the amount of the male hormone, testosterone, in the blood. Both men and women produce this hormone. The test described...
Read Article Now Book Mark Article - Low estradiol level in women
Estradiol
An estradiol test measures the amount of a hormone called estradiol in the blood. Estradiol is one of the main types of estrogens.
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Normal Results
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
An increased LH response suggests a problem in the ovaries or testes.
A reduced LH response suggests a problem with the hypothalamus gland or pituitary gland.
Abnormal results may also be due to:
- Pituitary gland problems, such as release of too much hormone (hyperprolactinemia)
Hyperprolactinemia
Prolactin is a hormone released by the pituitary gland. The prolactin test measures the amount of prolactin in the blood.
Read Article Now Book Mark Article - Large pituitary tumors
Pituitary tumors
A pituitary tumor is an abnormal growth in the pituitary gland. The pituitary is a small gland at the base of the brain. It regulates the body's ba...
Read Article Now Book Mark Article - Decrease in hormones made by the endocrine glands
Endocrine glands
Endocrine glands release (secrete) hormones into the bloodstream. The endocrine glands include:AdrenalHypothalamusIslets of Langerhans in the pancrea...
Read Article Now Book Mark Article - Too much iron in the body (hemochromatosis)
Hemochromatosis
Hemochromatosis is a condition in which there is too much iron in the body. It is also called iron overload.
Read Article Now Book Mark Article - Eating disorders, such as anorexia
Anorexia
Anorexia is an eating disorder that causes people to weigh less than is considered healthy for their age and height, usually by excessive weight loss...
Read Article Now Book Mark Article - Recent significant weight loss, such as after bariatric surgery
- Delayed or absent puberty (Kallmann syndrome)
- Lack of periods in women (amenorrhea)
Amenorrhea
Absence of a woman's monthly menstrual period is called amenorrhea. Primary amenorrhea is when a girl has not yet started her monthly periods, and sh...
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Risks
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks related to having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Reviewed By
LaQuita Martinez, MD, Department of Obstetrics and Gynecology, Emory Johns Creek Hospital, Alpharetta, GA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Guber HA, Oprea M, Russell YX. Evaluation of endocrine function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 25.
Kaiser U, Ho K. Pituitary physiology and diagnostic evaluation. In: Melmed S, Auchus, RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 8.
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