The LH blood test measures the amount of luteinizing hormone (LH) in blood. LH is a hormone released by the pituitary gland, located on the underside of the brain.
A blood sample is needed.
Your health care provider will ask you to temporarily stop medicines that may affect the test results. Be sure to tell your provider about all the medicines you take. These include:
If you are a woman of childbearing age, the test may need to be done on a specific day of your menstrual cycle. Tell your provider if you have recently been exposed to radioisotopes, such as during a nuclear medicine test.
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
In women, an increase in LH level at mid-cycle causes release of eggs (ovulation). Your doctor will order this test to see if:
If you are a man, the test may be ordered if you have signs of infertility or lowered sex drive. The test may be ordered if you have signs of a pituitary gland problem.
Normal results for adult women are:
LH levels are normally low during childhood.
Normal result for men over 18 years of age is around 1.8 to 8.6 IU/L.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test result.
In women, a higher than normal level of LH is seen:
In men, a higher than normal level of LH may be due to:
In children, a higher than normal level is seen in early (precocious) puberty.
A lower than normal level of LH may be due to the pituitary gland not making enough hormone (hypopituitarism).
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
Reviewed By: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.