The LH test contains 1 test with 1 biomarker.
Description: A Luteinizing Hormone, or LH, Test is a test that measures the level of the LH in the blood. It is used to predict ovulation, evaluate infertility and monitor during infertility treatment, or identify a pituitary disorder. It can also help along with several other hormone test to evaluate the cause of irregular menstrual cycles.
Also Known As: Luteinizing Hormone Test, Lutropin Test, Interstitial Cell Stimulating Hormone Test, ICSH Test
Collection Method: Blood Draw
Specimen Type: Serum
Test Preparation: No preparation required
When is an LH test ordered?
LH testing may be ordered in adults when:
- A woman is having trouble conceiving or has irregular or non-existent menstrual cycles.
- When a woman's menstrual cycle has stopped or grown irregular, or it is suspected that she has entered menopause.
- When a man's partner is unable to conceive, when he has low testosterone levels, or when he has poor muscular mass or decreased sex drive.
- Unexplained weight loss, exhaustion and weakness, and decreased appetite are just a few examples of signs and symptoms that may be present when a health professional suspects a pituitary issue.
When a boy or girl does not appear to be entering puberty at the appropriate age, LH may be ordered. Puberty symptoms include:
- Breast enlargement in young women
- Pubic hair development
- Boys' testicles and penis grow.
- In girls, menstruation begins.
What does an LH blood test check for?
Luteinizing hormone is a hormone linked to reproduction and the stimulation of ovarian egg release in women, as well as testosterone production in males. This test determines how much luteinizing hormone is present in the blood.
The pituitary gland, a grape-sized structure near the base of the brain, produces LH. The hypothalamus in the brain, the pituitary gland, and the hormones generated by the ovaries and testicles all work together to control LH production.
Several hormones rise and fall in a certain order in premenopausal women's bodies during each menstrual cycle. LH increases ovulation and the generation of other hormones such as estradiol and progesterone during the menstrual cycle.
Each phase of a woman's menstrual cycle lasts roughly 14 days and is separated into follicular and luteal stages. A mid-cycle surge of follicle-stimulating hormone and LH occurs near the end of the follicular phase. Ovulation is triggered by this surge, which results in the rupture of the egg follicle on the ovary and the release of the egg.
The place where the egg follicle ruptured becomes a "corpus luteum" during the luteal phase. The corpus luteum is stimulated to begin generating progesterone by LH release. While FSH and LH levels decrease, progesterone and estradiol levels rise. If the egg is not fertilized, these hormone levels will drop after a few days. Menstruation begins, and then the cycle repeats itself.
Ovarian function declines and eventually quits as a woman matures and approaches menopause. FSH and LH levels rise as a result of this.
LH stimulates the testicles' Leydig cells to create testosterone in men. After adolescence, men's LH levels remain generally steady. A high level of testosterone sends negative feedback to the pituitary gland and hypothalamus, reducing the amount of LH released.
LH levels in newborns and youngsters peak shortly after delivery and then drop to extremely low levels. Levels begin to rise again at the age of 6-8 years, just before puberty and the development of secondary sexual traits.
Lab tests often ordered with an LH test:
- Sperm Analysis
- Anti-Mullerian Hormone
- Sex Hormone Binding Globulin
Conditions where an LH test is recommended:
- Pituitary Disorders
- Endocrine Disorders
How does my health care provider use an LH test?
There are various applications for the luteinizing hormone test, which is a hormone linked to production and the stimulation of the release of an egg from the ovary in women and testosterone synthesis in males.
LH is frequently used in conjunction with other tests in both women and men:
- In the investigation of infertility,
- To help with the diagnosis of pituitary diseases that impact LH production.
- To aid in the diagnosis of diseases involving the ovaries or testicles
FSH and LH are used to diagnose delayed and precocious puberty in children. Puberty timing irregularities could indicate a more significant disease involving the hypothalamus, pituitary gland, ovaries, testicles, or other systems. LH and FSH levels can help distinguish between benign symptoms and real disease. Once it's been determined that the symptoms are due to an actual condition, more testing can be done to figure out what's causing them.
LH is occasionally evaluated in response to gonadotropin releasing hormone treatment in those with evidence of impaired ovarian or testicular function to distinguish between problems involving the brain or pituitary gland. The hypothalamus produces GnRH, which stimulates the pituitary gland to release LH and FSH. A baseline blood sample is taken for this test, and then the subject is given a GnRH injection. Following that, blood samples are collected at predetermined intervals and the level of LH is monitored. This test can assist distinguish between a pituitary disorder, in which LH does not respond to GnRH, and a hypothalamic disorder, in which LH does respond to GnRH. It's also useful for determining if a child is precocious or delayed in puberty.
What do my LH test results mean?
Primary ovarian failure and secondary ovarian failure can be distinguished using LH and FSH levels.
Primary ovarian failure is characterized by elevated levels of LH and FSH.
Multiple LH tests can be done to detect the surge that precedes ovulation in women who are attempting to conceive. Ovulation has happened when LH levels rise.
Because a woman's ovaries stop working during menopause, her LH levels rise.
Secondary ovarian failure is characterized by low levels of LH and FSH, which indicate a problem with the pituitary or hypothalamus.
LH levels that are too high could suggest primary testicular failure. This can be caused by testicular injury or developmental problems in testicular growth.
Low levels of LH and FSH are detected in secondary testicular failure and reflect a pituitary or hypothalamic issue.
For both men and women
The LH response to GnRH can assist distinguish between secondary and tertiary dysfunction. After determining the baseline level of LH, a dosage of GnRH is administered through injection. The fact that the pituitary responded to the GnRH and that the level of LH increased afterward suggests a hypothalamic problem. A low amount of LH indicates that the pituitary did not respond to GnRH and points to a pituitary illness.
Precocious puberty is defined as high levels of LH and FSH together with the development of secondary sexual characteristics at an unusually young age in young children. This occurs far more frequently in girls than in boys. This abnormal development is usually caused by a problem with the central nervous system, which can have a variety of causes.
Normal FSH and LH levels with a few indications of puberty could indicate a benign form of precocious puberty with no underlying or discernible reason, or it could simply be a normal variation of puberty. LH and FSH levels can be normal or below what is expected for a child of this age range in delayed puberty. In addition to other tests, the LH response to GnRH test may aid in determining the cause of delayed puberty. Delay in puberty can be caused by a variety of factors.
We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.