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Luteinizing Hormone

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). The level of LH in a woman's body varies with the phase of the menstrual cycle. It increases rapidly 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 menstrual 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 the cause for a couple's inability to become pregnant (infertility). LH testing is commonly used to help evaluate:
    • A woman's egg supply (ovarian reserve).
    • A man's sperm count.
  • Help evaluate menstrual problems, such as irregular or absent menstrual periods (amenorrhea). This can help determine if the woman has gone through menopause.
  • Determine 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.
  • Determine why sexual features or organs are not developing when they should (delayed puberty).
  • Determine (usually with a urine sample) when a woman is ovulating. Home urine tests for ovulation are available.
  • Monitor a woman's response to medicines given to stimulate ovulation.

How To Prepare

Many medicines, such as cimetidine, clomiphene, digitalis, and levodopa, can change your results. 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 having a luteinizing hormone (LH) test. Make sure your doctor has a complete list of all the prescription and over-the-counter medicines you are taking, including herbs and natural substances.

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

Let your doctor know the first day of your last menstrual period. If your bleeding pattern is light or begins 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, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

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.
  • Apply a gauze pad or cotton ball over the needle site as the needle is removed.
  • Apply pressure to the site and then a bandage.

For women, more than one blood sample may be needed to get an accurate indication of 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 determine 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 home ovulation testing on a urine sample.

  • Place the collection container into the stream of urine and collect approximately 4 Tbsp (60 mL) 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 color indicator on it that can detect luteinizing hormone (LH).

How It Feels

Blood test

You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. But many people do not feel any pain (or have only minor discomfort) once the needle is positioned in the vein.

Urine test

Collecting a urine sample does not normally cause any discomfort.

Risks

Blood test

  • You may develop a small bruise at the puncture site. You can reduce the risk of bruising by keeping pressure on the site for several minutes after the needle is withdrawn.
  • In rare cases, the vein may become inflamed after the blood sample is taken. This condition is called phlebitis and is usually treated with a warm compress applied several times daily.
  • Continued bleeding can be a problem for people who have bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can also make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood is drawn.

Urine test

There are no risks linked with collecting a urine sample.

Results

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

LH levels depend on a person's age and stage of sexual development, and, in a woman, on the phase of her menstrual cycle. The urine test to determine whether a woman is ovulating detects only the presence (positive result) or absence (negative result) of LH.

Normal

The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab. Ask your doctor for normal values of your luteinizing hormone test.

Luteinizing hormone in blood 1
Menstruating women  

Follicular phase:

1.68–15 international units per liter (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 determine only the presence of LH (called qualitative testing) and not the specific level or quantity. 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 significant abnormal 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 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 functioning 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 luteinizing hormone test may be affected by:

  • The use of certain hormones, including those containing estrogen or progesterone (such as birth control pills).
  • The use of medicines, such as clomiphene, spironolactone, naloxone, phenothiazine, and those 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 are taking a medicine that contains testosterone, estrogen, or progesterone (such as birth control pills), ask your doctor whether you should stop taking it for several days before having a luteinizing hormone (LH) test.
  • You can buy home ovulation kits at a drugstore to help identify the most fertile days of a woman's menstrual cycle. The kits test for LH in urine with a dipstick or test strip. Other home ovulation tests that measure the amount of LH in urine and display the results on a small computerized monitor also are available.
  • 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

By Healthwise Staff
Sarah Marshall, MD - Family Medicine
Femi Olatunbosun, MB, FRCSC - Obstetrics and Gynecology
Last Revised February 22, 2013

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