Alternate Names : Luteinizing Hormone
The LH test is a blood test that measures the amount of luteinizing hormone (LH) produced by the pituitary gland. In men, LH stimulates the production of testosterone by the testes. In women, LH is one of the hormones involved in the monthly release of an egg from the ovaries.
Who is a candidate for the test?
Conditions that may call for LH evaluation in women include:
amenorrhea, or absence of menstruation
infertility, which is the inability to become pregnant
irregular menstrual cycles
vaginal bleeding without ovulation
A man may have an LH test if he has hypogonadism, or underdeveloped testes.
How is the test performed?
A blood sample is taken from a vein on the forearm or hand. First, the skin over the vein is cleaned with an antiseptic. Next, a strong rubber tube, or tourniquet, is wrapped around the upper arm. This enlarges the veins in the lower arm by restricting blood flow through them. A fine needle is gently inserted into a vein, and the tourniquet is removed. Blood flows from the vein through the needle and is collected in a syringe or vial. After the needle is withdrawn, the puncture site is covered with a bandage for a short time to prevent bleeding.