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 sensation. Afterward, there may be some throbbing or a slight bruise. These soone go 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 result for an 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.
IU/L stands for international unit per liter.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor 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).
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
Reviewed By: Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.