LH Test

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Formal name: Luteinising hormone

At a Glance

Why Get Tested?

To evaluate the function of your pituitary gland, which regulates the hormones that control your reproductive system

When to Get Tested?

If you are having difficulty getting pregnant or are having irregular menstrual periods or when your doctor suspects that a child has delayed or earlier than expected sexual maturation.

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Luteinising hormone (LH) is produced by the pituitary gland in the brain. Control of LH production is a complex system involving hormones produced by the gonads (ovaries or testes), the pituitary gland, and the hypothalamus, such as gonadotrophin-releasing hormone (GnRH).

Women’s menstrual cycles are divided into 2 phases, the follicular and luteal, by a mid-cycle surge of follicle-stimulating hormone (FSH) and LH. The high level of LH (and FSH) at mid-cycle triggers ovulation (release of the egg from the ovary). LH also stimulates the ovaries to produce other hormones, mainly oestradiol. Oestradiol helps the pituitary gland to control the production of LH. At the time of the menopause, the ovaries stop functioning and LH levels rise.

In men, LH stimulates the Leydig cells in the testes to produce testosterone. LH levels are relatively constant in men after puberty.

In infants and children, LH levels rise shortly after birth and then fall to very low levels (by 6 months in boys and 1-2 years in girls). At about 6-8 years, levels again rise with the beginning of puberty and the development of secondary sexual characteristics such as pubic hair, deepening voice in males and pubic hair and breast development in girls.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is required, but woman’s sample should be collected at specific times during her menstrual cycle usually during the first few days of the cycle.

The Test

Common Questions

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.