Luteinizing Hormone

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.

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 whether the woman has gone through menopause.
• Determine whether 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.

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 health professional 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 indicate. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

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 (59 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).

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. However, 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.

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.
• Rarely, 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 with 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 associated with collecting a urine sample.

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

Normal values vary widely among labs and methods used. Ask your doctor for normal values of your luteinizing hormone test.

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 medical history.

High values

High luteinizing hormone values in a woman may indicate:

• 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 indicate:

• 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 indicate:

• Anorexia nervosa.
• Pituitary gland failure.
• Damage to a part of the brain called the hypothalamus.
• Stress.
• Low body weight.

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, digoxin, phenothiazine, and those given for seizures (anticonvulsants).
• Obesity.
• Hyperthyroidism.
• Liver disease.
• 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.

• 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.
• A woman can buy home ovulation kits at a drugstore to help identify the most fertile days of her menstrual cycle. They 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. For more information, see the medical test Fertility Awareness.

Other Works Consulted

• Chernecky CC, Berger BJ, eds. (2004). Laboratory Tests and Diagnostic Procedures, 4th ed. Philadelphia: Saunders.

• Fischbach FT, Dunning MB III, eds. (2004). Manual of Laboratory and Diagnostic Tests, 7th ed. Philadelphia: Lippincott Williams and Wilkins.

• Handbook of Diagnostic Tests (2003). 3rd ed. Philadelphia: Lippincott Williams and Wilkins.

• Pagana KD, Pagana TJ (2002). Mosby’s Manual of Diagnostic and Laboratory Tests, 2nd ed. St. Louis: Mosby.