Leutinising Hormone (LH) Test

The LH test determines the amount of luteinizing hormone in the blood. The pituitary gland situated underneath the brain releases this hormone. LH plays a vital role in sexual development and functioning. It plays a vital role in the functioning of the reproductive system of both men and women.

In women, the pituitary releases Luteinizing Hormone (LH) in the blood during the menstrual cycle. This hormone helps the ovary to release a mature egg. This process is called ovulation.

In men, Luteinizing Hormone helps the testicles make testosterone, a hormone essential for sperm production.

Children have low levels of LH during early childhood. The hormone levels begin to rise 1-2 years before the start of puberty. In adolescent girls, LH signals the ovaries to make estrogen, whereas, in boys, it signals the testes to produce testosterone.

Fluctuations in the level of LH in the blood can lead to a variety of health-related problems. For example, higher than expected or lower than average levels of LH can lead to concerns like infertility, menstrual irregularities, early or late puberty in children and low sex drive in men.

Luteinizing Hormone works closely with another hormone called the Follicular Stimulating Hormone (FSH) to regulate sexual functions.

So, the LH test done is usually along with an FSH test. These tests help determine various things depending on your gender and age.

In women, an LH test can help find the cause of infertility, menstrual irregularities, and time of ovulation.

In men, this test helps to detect the cause of low sperm count, low sex drive, and the cause of infertility.

In children, this test helps to diagnose early or delayed puberty.

Infertility rates are on the rise worldwide. The infertility rate in India is between 3.9 to 16.8% (according to WHO). An LH test helps to determine the cause of infertility in both men and women. The average age of puberty in Indian girls has declined (according to a study in 2014). LH test helps to diagnose precocious (early) puberty in girls.

LH Test is Also Referenced as

Luteinizing Hormone (LH) test is also called the interstitial cell-stimulating hormone test or lutropin test.

What does the LH Test Detect/Measure, and who is this Prescribed for?

The LH test calculates the level of Luteinizing Hormone in the body. The doctor may prescribe this test for diagnosis, observation, or determining the ovulation time in females.

LH test could be prescribed for various reasons depending on the gender, age, and stage of the menstrual phase.

In females, it is usually performed in the case of the following:

• Irregular menstrual cycles
• Difficulty in getting pregnant
• To understand the start of menopause or perimenopause

In men, the LH test is done for the following reasons:

• Low sex drive
• To find the reason for infertility
• Low sperm count

LH test may be performed in children to diagnose:

• Early puberty
• Delayed puberty

Signs such as breast development, growth of pubic hair or beginning of the menstrual cycle before the age of 8 years in girls is termed precocious puberty.

In boys, signs of precocious puberty are the growth of testicles and penis and hair around the pubic area before the age of 9 years.

Similarly, when the above signs do not develop in girls by the age of 13 years and by the age of 14 years in boys, it is termed delayed puberty.

LH levels in adolescent children help diagnose early and late puberty.

This test may also be performed in the case of some brain disorders such as pituitary or hypothalamic disorders.

The reference range for the LH test is defined based on age, gender, stage of sexual development, medications, menstrual status, and pregnancy.

The interpretation of the test also depends on gender and age.

In females, higher than normal levels of LH may indicate:

• Polycystic ovary syndrome (PCOS). PCOS is a common problem among women of childbearing age. It is one of the leading causes of female infertility.
• Absence of ovulation – In women of childbearing age, this may be the reason for infertility, and in women of menopausal age, this indicates the start of menopause or perimenopause.

Lower than normal levels of the hormone may indicate:

• Malnutrition
• Pituitary gland disorder

In Males, high levels of LH imply:

• Damage to the testicles (due to infection, alcohol abuse, chemotherapy, or radiation)
• Klinefelter's syndrome is a genetic disease that can lead to infertility in males.

Low levels of LH in males signify:

• Disorder of the hypothalamus
• Pituitary gland disorder

High levels of LH in children may indicate the beginning of puberty.

If this happens before the age of 9 years in a girl or before the age of 10 years in a boy, it may be due to

• Brain injury
• Central Nervous system disorder

Low levels of LH after the age of 13 years may be because of delayed puberty.

Delayed puberty is caused due to:

• Ovarian or testicular disorder
• Turner's syndrome in girls
• Klinefelter's syndrome in boys
• Infection
• Malnutrition

A blood sample is used to perform an LH test.

Test Preparation

The LH test is a simple blood test. There is no preparation required before performing the test. Before taking the test, one must inform their doctor of any ongoing medications, supplements, vitamins, or birth control pills. Some medicines may be stopped or reduced as they can give a false reading. In females, the test needs to be carried out during a specific time of the menstrual cycle. Therefore, women must give accurate dates of the menstrual cycle to their doctor.

Test Inclusions: What Parameters Are Included?

The LH test determines the level of Luteinizing Hormone in the bloodstream. In women, the amount of hormone in the body differs with age, during pregnancy and throughout the menstrual cycle. If the LH test is done for fertility-related issues, the doctor may ask to take multiple tests to check the hormone levels during the menstrual cycle.

In men, the LH test is done to determine the baseline level of the Luteinizing Hormone. The LH levels do not fluctuate much in adult males.

LH test may be done along with other hormonal tests such as the follicular stimulating hormone test (FSH). These tests are of great value in investigating precocious and delayed puberty, infertility (in both men and women), hypogonadism, polycystic ovarian disease, and some brain disorders.

How Frequently Should You Take This Test?

The repetition of the test depends on the reason for performing the test. If the LH test is done to check for fertility (getting pregnant) in women, the doctor may advise repeating the test a few times a month. This is done to understand the rise and fall of hormone levels during different menstrual phases.

For men and children, it may be performed just once to check the blood levels of LH in the body.

Determine the time of ovulation, Low sperm count, Pituitary and hypothalamic disorder