LH is a hormone secreted by the pituitary gland. In women it causes the ovaries to release a mature egg. In men, it causes the testes to make testosterone. The test is used in the workup of infertility, to aid in the diagnosis of pituitary disorders, to help diagnose ovarian or testicular dysfunctions, and in the investigation of menstrual irregularities.
Test is performed on a blood sample. No preparation is needed, but the result has to be correlated with the menstrual cycle in women