Content Map Terms

Luteinizing Hormone

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 woman's egg supply. (This is called the ovarian reserve.)
    • 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 gone 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 9 and in boys younger than age 10.
  • 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 cimetidine, clomiphene, and levodopa. 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.

Tell your doctor if you have had a test that used a radioactive substance (tracer) in the last 7 days. Recent tests (such as a thyroid scan or bone scan) using this kind of tracer can affect your LH test results.

Let your doctor know the first day of your last menstrual period. If your bleeding pattern is light or starts with spotting, the first day is the day of heaviest bleeding.

Talk to your doctor about any concerns you have regarding the need for the test or its risks. You can also ask how it will be done and what the results will mean. To help you understand the importance of this test, fill out the medical test information form .

How It Is Done

Blood test

The health professional drawing blood will:

  • Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
  • Clean the needle site with alcohol.
  • Put the needle into the vein. More than one needle stick may be needed.
  • Attach a tube to the needle to fill it with blood.
  • Remove the band from your arm when enough blood is collected.
  • Put a gauze pad or cotton ball over the needle site as the needle is removed.
  • Put pressure on the site and then put on a bandage.

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.

  • Place the collection container into the stream of urine. Collect about 60 mL (4 Tbsp) of urine.
  • Do not touch the rim of the container to your genital area. And do not get toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.
  • Finish urinating into the toilet.

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

How It Feels

Blood test

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may 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 a problem from having a blood sample taken from a vein.

  • You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. You can use a warm compress several times a day to treat this.

Urine test

Collecting a urine sample does not cause problems.

Results

A luteinizing hormone test measures the amount of luteinizing hormone (LH) in a sample of blood or urine.

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. The urine test to see if a woman is ovulating just finds out if a woman has LH in her body (positive result) or doesn't have LH in her body (negative result).

Normal

These numbers are just a guide. The range for "normal" varies from lab to lab. Your lab may have a different range. Your lab report should show what range your lab uses for "normal." Also, your doctor will evaluate your results based on your health and other factors. So a number that is outside the normal range here may still be normal for you. Ask your doctor for normal values of your test.

Luteinizing hormone in blood footnote 1

Menstruating women

Follicular phase:

1.68–15 international units per litre (IU/L)

Midcycle peak:

21.9–56.6 IU/L

Luteal phase:

0.61–16.3 IU/L

Women past menopause:

14.2–52.3 IU/L

Men:

1.24–7.8 IU/L

Luteinizing hormone in urine

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 functioning. 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:

What Affects the Test

Results of the test may be affected by:

  • The use of certain hormones, such as those containing estrogen or progesterone. This includes birth control pills.
  • The use of medicines, such as clomiphene, spironolactone, naloxone, and some given for seizures (anticonvulsants).
  • Diagnostic imaging procedures, such as a thyroid scan or bone scan, that use a radioactive substance (tracer) and were performed within 7 days prior to LH testing.
  • Obesity.
  • Hyperthyroidism.
  • Liver disease.

What To Think About

  • If you take a medicine that contains testosterone, estrogen, or progesterone (such as birth control pills), talk to your doctor. He or she may want you to stop taking it for several days before your test.
  • You can buy home ovulation kits at a drugstore to help find the most fertile days of a woman's menstrual cycle. The kits test for LH in urine with a dipstick or test strip. You can also buy home ovulation tests that measure the amount of LH in urine and show the results on a small computer monitor.
  • Other tests for ovulation include measuring basal body temperature, testing the progesterone level after ovulation in the menstrual cycle, and noting changes in cervical mucus. To learn more, see the topic Fertility Awareness.

References

Citations

  1. Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.

Other Works Consulted

  • Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.

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
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Femi Olatunbosun MB, FRCSC - Obstetrics and Gynecology
Rebecca Sue Uranga