Luteinizing Hormone (LH) test is a kind of blood test that is used to measure the amount of the LH hormone present in the blood. This hormone helps in the reproductive system as it is released by the pituitary gland and cause ovaries to release matured eggs or testes to secrete testosterone. The LH test can help find out the cause of infertility in males and females, to diagnose any kind of pituitary disorder like prolactinoma or any tumor in the pituitary gland. If women show infrequent or absence of menstrual periods or men show lower sex drive or low testosterone level then this test along with other tests can help doctors find out the real reason behind the symptom.
LH test results given in international units per liter (IU/L) vary in a woman as per the stage of her menstrual cycle. For men, the normal range is between 1.24 to 7.8 IU/L while for women it may be 1.68 to 15 IU/L (follicular phase of the cycle) or 0.61 to 16.3 IU/L in Luteal phase while for postmenopausal it is between 14.2 to 52.3 IU/L. When LH level in woman’s blood is higher than normal it may indicate a problem with ovaries and the lower level may indicate a pituitary disorder, malnutrition and others. In men, high level of LH indicates testicles problem while lower than normal level of LH may indicate any problem with the pituitary gland or hypothalamus.