Luteinizing Hormone Test-Why am I having this test?

Luteinizing hormone (LH) is a hormone that is made by the pituitary gland in the brain. LH plays an important role in the ability to have children (fertility). In women, LH carries chemical signals to the ovaries to release eggs each month for possible fertilization (ovulation).

In men, LH signals the testicles to produce the male sex hormone (testosterone). You may have an LH test to help diagnose the cause of:

• Inability to have children (infertility).
• Irregular or loss of menstrual periods in women.
• Pituitary gland problems.
• Low testosterone in men.
• Early or late sexual development (puberty) in children.

What is being tested?

This test measures the amount of LH in the blood.

The level of LH in the body can change at different times. It varies as you grow and age. It also changes over the course of a woman’s menstrual cycle.

What kind of sample is taken?

A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel.

How do I prepare for this test?

• If you are having this test to check for ovulation problems, you may need to schedule the test in the middle of your menstrual cycle. Know the date that your most recent period started. Your health care provider may ask you this.
• Follow instructions from your health care provider about changing or stopping your regular medicines. This is especially important if you are taking:
  • Birth control pills.
  • Hormone replacements or supplements.
  • Anti-seizure drugs.
  • A heart medicine called digoxin.

Tell a health care provider about:

• All medicines you are taking. This includes birth control pills, supplements, vitamins, herbs, eye drops, creams, and over-the-counter medicines.
• Any medical conditions you have, especially any tumors or hypothyroidism.
• Whether you are pregnant or may be pregnant.

How are the results reported?

Your results will be reported as a value that indicates how much LH is in your blood. This will be given as international units of LH per liter of blood (IU/L).

Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common normal reference ranges are:

• Adult female:
  • If you have not gone through menopause, your reference ranges vary based on where you are in your menstrual cycle:
    • Follicular phase: 1.68–15 IU/L.
    • Ovulatory peak: 21.9–56.6 IU/L.
    • Luteal phase: 0.61–16.3 IU/L.
  • If you have gone through menopause (are postmenopausal), your reference range is 14.2–52.3 IU/L.
• Adult male: 1.24–7.8 IU/L.
• Children younger than 10 years:
  • Male: 0.04–3.6 IU/L.
  • Female: 0.03–3.9 IU/L.

What do the results mean?

A result that is within your reference range is considered normal, meaning that you have a normal amount of LH in your blood.

A result that is higher than your reference range means that there is too much LH in your blood.

• In adult women, this may mean that your ovaries are not ovulating normally. This may be caused by many things, including:
  • Menopause.
  • An ovarian tumor.
  • Polycystic ovarian syndrome (PCOS).
  • Disease of the thyroid or adrenal gland.
  • Damage to the ovaries, such as from radiation therapy or chemotherapy.
  • Problems with the pituitary gland.
• In adult men, this may mean that the testicles are not making enough testosterone. This may cause symptoms such as low sex drive, fatigue, or sexual dysfunction. Low testosterone production may be caused by many things, including:
  • Tumors.
  • Damage to the testicles, such as from injury, radiation therapy, or chemotherapy.
  • Certain viral infections.
  • A disorder of the hypothalamus, which is a part of the brain that is involved in the release of hormones.
  • Problems with the pituitary gland.
• In children younger than 10, this may mean that puberty is starting early (precocious puberty).

A result that is lower than your reference range means that there is too little LH in your blood. In men or women, this may be caused by:

• A pituitary gland disorder.
• Lack of nutrients in the diet (malnutrition).
• High stress levels.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• Luteinizing hormone (LH) is a hormone made by the pituitary gland in the brain. It plays an important role in the ability to have children (fertility).
• A test result that is within your reference range is considered normal, meaning that you have a normal amount of LH in your blood.
• Results that are higher or lower than the reference range can be used to help your health care provider diagnose a variety of conditions. Talk with your health care provider about what your results mean.