Luteinizing hormone, also often known simply as LH, is a test which is performed along with other tests like Follicle Stimulating Hormones, FSH, progesterone, testosterone and estradiol. These tests are performed to check for infertility in both men and women. Additional testing of LH may also be done to investigate irregularities in the menstruation cycle and to help diagnose disorders of the pituitary gland which may affect the ovaries and the testes.
The LH may be tested in blood or urine. To determine the ovulation cycle, a baseline test is first performed on the urine and then subsequent tests are performed to check for the surge, if any, in the amount of LH.
If a child has a delayed puberty, or an early one, both the LH and the FSH are tested. In some cases, a luteinizing hormone test may also be prescribed to help distinguish the disorders of the endocrine glands from the disorders of the gonadotropin releasing hormones. In such a testing a luteinizing hormone blood test is required. A blood sample is first drawn at a particular time in the day and used as a baseline sample. After this, the patient is injected with gonadotropin releasing hormone and then more blood samples are drawn at different intervals and the levels of luteinizing hormones are then measured.
The interpretation of test results is different in men and women and is dependant on the various factors behind the testing. In women, abnormal LH levels may help in the diagnosis of development failure of the ovaries. The results may also be able to help the doctor distinguish between primary and secondary ovarian failure. The test results may also be indicative of abnormalities in the chromosomes which lead to diseases like Kallmann's syndrome or the Turner's syndrome. Another defect that the ovaries can indicate is the deficiency in the production of steroids in the ovaries.
If the patient has been undergoing intense therapy for cancer and has been receiving radiation or chemotherapy, the tests can help diagnose premature ovarian failure caused by them. The test can also help diagnose premature ovarian failure due to autoimmune diseases. Chronic failure due to other diseases like adrenal disease, ovarian tumors, polycystic ovarian syndrome and thyroid disease could also be diagnosed.
If in a luteinizing hormone blood test, the LH values are seen to be particularly high, it may be an indication of menopause. In men, if the LH levels are high, it may be an indication of primary testicular failure.