Luteinizing hormone (LH) test: Uses, ranges, and results

A luteinizing hormone test measures how much luteinizing hormone a person has in their blood. This is a hormone with key roles in both male and female reproductive systems.

Luteinizing hormone (LH) is involved in many bodily processes, including pregnancy, puberty, and ovulation. LH levels increase or decrease at various points during these cycles.

This article explores the uses of LH tests. It discusses high, low, and normal LH levels, as well as what they mean and how they relate to pregnancy.

What is an LH test?

Gloved hand holding LH blood test sample
An LH test involves taking a blood sample.

An LH test is a type of blood test that measures a person’s LH levels.

LH is made in the pituitary gland of the brain. LH is a sex hormone that affects how a person’s reproductive organs work. In females, LH affects the ovaries. In males, it affects the testes.

Reproductive health problems can affect a person’s LH levels.

LH is involved in the following bodily processes:

Puberty: LH levels affect the onset of puberty. High LH levels may cause early puberty and low LH levels may delay puberty.

Menstruation: LH works with another sex hormone called follicle-stimulating hormone (FSH) to control menstrual cycles.

Ovulation: An increase in LH, called an LH surge, triggers the release of an egg from an ovary.

Progesterone release: An increase in LH triggers ovulation. The cell structure that is left after ovulation releases progesterone. Progesterone is needed to maintain a pregnancy.

Testosterone production: LH binds to Leydig cells in the testes and triggers testosterone production. Testosterone levels affect sex drive.

Sperm production: Testosterone, which LH levels affect, is needed for sperm production.

What is an LH test used for?

We explore the various uses of LH tests below:

Fertility problems

Doctors use LH tests to help diagnose fertility problems in both males and females. If a couple is having difficulty become pregnant, there may be a problem with:

sperm count

the egg supply from the ovaries

A person’s LH levels can tell the doctor whether a person is having problems with their sperm count or egg supply. Either issue could make it more difficult for a person to become pregnant.


People can measure their LH levels to find out how fertile they are on different days. LH levels surge just before ovulation, signaling the most fertile period of a female’s menstrual cycle.

To identify the fertile period, people can check their LH levels at home. They can do this using ovulation urine tests. These home tests can detect the surge in LH that happens 1–1.5 days before ovulation.

Ovulation test kits normally contain several urine tests. The best time to use them is around the middle of the menstrual cycle, which is usually when a female ovulates. This may help her determine when she is about to ovulate.

Having sex around the time of ovulation is a good idea if a couple wants to become pregnant.

Menstrual changes

When a woman goes through menopause, her LH levels rise. For this reason, LH tests can help a doctor diagnose a person’s menstrual changes or problems.

Early or late puberty

LH levels can help a doctor determine why a child or teenager may have started puberty early or late. High LH levels may cause early puberty. Low LH levels may cause late puberty.

Pituitary gland problems

LH is made in the pituitary gland. Measuring LH levels can help determine whether there is a problem with the pituitary gland.

Low testosterone

Man inspecting beard in mirror
Low testosterone can cause reduced beard growth.

LH tests can help a doctor diagnose low testosterone in a male. Symptoms of low testosterone include:

low sex drive

problems getting or maintaining an erection

reduced beard growth

extreme tiredness


loss of muscle mass

being overweight


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