Also Known As
Interstitial cell stimulating hormone
Luteinizing hormone
Formal Name
Luteinising hormone
This article was last reviewed on
This article waslast modified on 23 March 2023.
At a Glance
Why Get Tested?

If a couple are having difficulty achieving a pregnancy or a woman is having irregular menstrual periods or when a child has delayed and precocious (early) puberty.

When To Get Tested?

In women: Days 1-5 of the menstrual cycle (during menstruation or bleeding)
In men: Samples can be taken at any time
In children: Samples can be taken at any time

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

No test preparation is usually required

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

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) 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 and progesterone. Oestradiol helps the pituitary gland to control the production of LH. At the time of the menopause, the ovaries stop functioning and LH concentrations rise.

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

In infants and children, LH rises shortly after birth and then falls 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.

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 phase.

Accordion Title
Common Questions
  • How is it used?

    LH is often used in conjunction with other tests (FSH, testosterone, oestradiol and progesterone) in the investigation of infertility in both men and women. LH measurements are also useful in the investigation of menstrual irregularities (irregular periods) and to aid in the diagnosis of pituitary gland disorders. In children, FSH and LH are used to diagnose delayed and precocious (early) puberty.

  • When is it requested?

    In women: Days 1-5 of the menstrual cycle (during menstruation or bleeding)
    In men: Samples can be taken at any time
    In children: Samples can be taken at any time. Sometimes sampling for LH and FSH happens after an injection of gonadotrophin releasing hormone (GnRH). This stimulates the pituitary gland to produce LH and FSH.

  • What does the test result mean?

    In women, FSH and LH results can help to tell the difference between primary ovarian failure (failure of the ovaries themselves) and secondary ovarian failure (failure of the ovaries due to disorders of either the pituitary gland or the hypothalamus in the brain). Increased FSH and LH are consistent with primary ovarian failure. Some causes of primary ovarian failure are listed below.

    Developmental defects:

    • Ovarian agenesis (failure to develop ovaries) 
    • Chromosomal abnormality, such as Turner’s syndrome
    • Ovarian steroidogenesis (steroid hormone production) defect, such as 17 alpha hydroxylase deficiency

    Premature ovarian failure due to: 

    Chronic anovulation (failure to ovulate) due to: 

    When a woman enters the menopause and her ovaries stop working, FSH and LH will rise. Note that LH should not be measured specifically to diagnose the menopause. In women above the age of 45 menopause can usually be diagnosed clinically. In younger women, and for investigation of premature ovarian insufficiency, FSH is the appropriate test.

    Low FSH and LH are consistent with secondary ovarian failure due to a pituitary or hypothalamic problem.

    In men, LH controls the production of testosterone from the testes and FSH controls the production of sperm. High LH and FSH may be due to primary testicular failure. This can be due to developmental defects in testicular growth or to testicular injury, as indicated below.

    Developmental defects: 

    • Gonadal agenesis (failure to develop testes) 
    • Chromosomal abnormality, such as Klinefelters syndrome

    Testicular failure:

    • Viral infection (mumps) 
    • Trauma 
    • Radiation therapy 
    • Chemotherapy 
    • Autoimmune disease 
    • Germ cell tumour

    Low levels of LH and FSH are consistent with pituitary or hypothalamic disorders.

    In young children, high levels of FSH and LH and development of secondary sexual characteristics at an unusually young age are an indication of precocious (early) puberty. This is much more common in girls than in boys.

  • Is there anything else I should know?

    LH results can be increased with use of certain drugs, such as cimetidine, clomiphene, digitalis, and levodopa. LH results can decrease with oral contraceptives (the pill), phenothiazines, and other hormone treatments.

  • I'm having a hard time getting pregnant. What tests do I need?

    The basic test for infertility is measurement of progesterone to check that ovulation is occurring. Other tests for infertility include FSH and LH and other blood tests to assess your reproductive hormone levels. A post-coital test may be carried out where the cervical mucous is examined 2-8 hours after intercourse to check if the sperm are surviving in it. A hysterosalpingogram (image of fallopian tubes) may be done to see whether your fallopian tubes are blocked. Your partner may be asked to give a specimen of semen for analysis.

  • Why would a man need a test for female hormones?

    Men also produce FSH and LH in the pituitary gland and these hormones are important for male reproduction. In men, FSH stimulates the testes to produce sperm just as in women FSH stimulates the ovaries to produce eggs. In men, LH stimulates the production of testosterone in the testes and may be measured to investigate the cause of a low testosterone.