Patient education: Luteinizing hormone test (The Basics)

What is a luteinizing hormone test? — 

This is a test to measure the amount of luteinizing hormone, or "LH," in the blood or urine. LH is a hormone made by the pituitary gland. The pituitary gland is a small organ located just below the brain (figure 1).

LH is involved in:

●Puberty – In teens, levels of LH and other hormones normally rise as the body gets ready to go through puberty.

●Fertility – In males, LH makes the testicles produce testosterone, which is needed to make sperm. In females, LH is important for ovulation, which is when the ovary releases an egg each month.

Having too much or too little LH can be a sign of a health problem.

Why might I get an LH test? — 

The doctor might order a blood LH test:

●To learn more about early or late puberty – For example, if a child has signs of early puberty or if a teen has not gone through puberty at the expected time, an LH test and other tests can give more information.

●To help figure out the cause of missed or irregular periods

●To check for causes of male infertility – This is when a person has trouble getting a partner pregnant. The LH level and other tests can help the doctor figure out why a person has too few sperm.

●If you will be going through in vitro fertilization, or "IVF" – This is a procedure used to treat infertility. It involves using sperm to fertilize an egg in a lab, then putting the egg into the uterus to grow into a pregnancy. Doctors do an LH test and other tests before IVF.

●If you have other symptoms that suggest problems with hormones

There are also home tests that females can use to check for LH in their urine. Your doctor might recommend using this type of test to help predict when you will ovulate. This can help if you are trying to get pregnant. If you are using a home kit, follow the instructions carefully.

How do I prepare for an LH test? — 

For the blood test, you will most likely need to have a "blood draw." Your doctor or nurse will tell you where to go for this.

It might help to wear a short-sleeve shirt to your blood draw appointment. This makes it easier for the person drawing your blood to get to your arm.

What happens during a blood draw? — 

A needle is used to take a small amount of blood from your arm (figure 2). Collecting the blood only takes a few minutes. The blood is then tested in a lab.

Tell the person who takes your blood:

●If you take "blood thinner" medicines or have a bleeding problem – They will make sure your bleeding is under control before you leave.

●If you have a latex allergy – Some of the supplies used for blood draws might contain latex.

●If you have a preferred arm to use

Most of the time, getting blood taken does not cause problems. You might have a little soreness or bruising where the needle went in.

What do my results mean? — 

Your doctor or nurse will tell you when to expect your results and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.

If the test shows your LH levels are too high or too low, your doctor or nurse will talk to you about what to do next. They might need to do more tests to figure out what the cause is.

If you do have a health problem, your doctor will work with you to come up with a plan for treatment.

More on this topic

Patient education: Early puberty (The Basics)
Patient education: Late puberty (The Basics)
Patient education: Absent or irregular periods (The Basics)
Patient education: Infertility in couples (The Basics)
Patient education: Male infertility (The Basics)

Patient education: Absent or irregular periods (Beyond the Basics)
Patient education: Evaluation of infertility in couples (Beyond the Basics)
Patient education: In vitro fertilization (IVF) (Beyond the Basics)