Health Library

Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein.

Luteinizing Hormone (LH) Test

Test Overview

A luteinizing hormone test measures the amount of luteinizing hormone (LH) in a sample of blood or urine. LH is produced by the pituitary gland.

  • In women, LH helps regulate the menstrual cycle and egg production (ovulation). How much LH is in a woman's body depends on the phase of her menstrual cycle. This hormone goes up fast just before ovulation occurs, about midway through the cycle (day 14 of a 28-day cycle). This is called an LH surge. Luteinizing hormone and follicle-stimulating hormone levels rise and fall together during the monthly cycle.
  • In men, LH stimulates the production of testosterone, which plays a role in sperm production.

Why It Is Done

A luteinizing hormone (LH) test may be done to:

  • Help find out why a couple can't become pregnant (infertility). LH testing is often used to help evaluate a man's sperm count.
  • Help to check for menstrual problems, such as irregular or absent menstrual periods (amenorrhea). This can help see if the woman has started to go through menopause.
  • Find out if a child is going through early puberty (also called precocious puberty). Puberty is early when it starts in girls younger than age 8 and in boys younger than age 9.
  • Find out why sexual features or organs are not developing when they should (delayed puberty).
  • Find out (usually with a urine sample) when a woman is ovulating. Home urine tests for ovulation are available.
  • Check for a woman's response to medicines given to stimulate ovulation.

How To Prepare

Many medicines can change your results. Some examples are clomiphene, testosterone, and metformin. You may be asked to stop taking medicines (including birth control pills) that contain estrogen or progesterone or both for up to 4 weeks before your luteinizing hormone (LH) test. Make sure your doctor has a complete list of all the prescription and over-the-counter medicines you take, including herbs and natural substances.

How It Is Done

Blood test

A health professional uses a needle to take a blood sample, usually from an arm.

For women, more than one blood sample may be needed to get a true reading of the luteinizing hormone (LH) levels. Several blood samples may be taken in one day. Or one sample may be taken each day for several days in a row.

Urine test for ovulation

To find out if you are ovulating, a sample of your first urine of the morning is usually tested. It is important to follow the package directions exactly if you are doing the test yourself at home.

You may also be given a plastic test strip to place in your urine stream. The test strip has a color indicator on it that can detect luteinizing hormone (LH).

Watch

How It Feels

Blood test

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Urine test

It is not painful to collect a urine sample.

Risks

Blood test

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Urine test

Collecting a urine sample does not cause problems.

Results

How much LH a person has depends on his or her age and stage of sexual development. In a woman, it also depends on the phase of her menstrual cycle.

Normal

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

Most home urine tests to predict ovulation just look for the presence of LH, not how much LH is present. Home urine test results are either "positive" (LH is present) or "negative" (LH is not present).

Many conditions can change LH levels. Your doctor will discuss any important results with you in relation to your symptoms and past health.

High values

High luteinizing hormone values in a woman may mean:

  • Ovaries are absent or have been removed.
  • Ovaries are not working as they should. This could be because of menopause, polycystic ovary syndrome (PCOS), or damage from chemotherapy.
  • Early puberty in young girls.

High luteinizing hormone values in a man may mean:

  • Testicles are absent or have been removed.
  • Testicles are not working as they should. This could be because of surgery or damage from mumps, X-ray exposure, chemotherapy, cancer, or injury.
  • Klinefelter syndrome.

Low values

Low luteinizing hormone values in a man or woman may mean:

Credits

Current as of: July 17, 2020

Author: Healthwise Staff
Medical Review:
Sarah Marshall MD - Family Medicine
Martin J. Gabica MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Kathleen Romito MD - Family Medicine
RSURemoved