Luteinizing Hormone (LH)

What sample is needed for Luteinizing Hormone (LH)?

1. The serum of the patient is required.
2. Avoid hemolysis.
3. A 24-hour urine sample may be collected. Refrigerate the urine during collection.
4. The serum is stable for 8 days at room temperature.
5. The serum is stable for 14 days at 4 °C.
6. The urine sample should not contain preservatives.

What are the Indications for Luteinizing Hormone (LH)?

1. LH, along with FSH, helps determine menopause.
2. LH is helpful in evaluating gonadal failure.
3. LH helps work up infertility cases.
   1. LH’s essay tells about the occurrence of ovulation.
4.  It tells gonadal failure (insufficiency):
   1. Primary when the problem is in the ovary (or the testes).
   2. Secondary when the problem is in the pituitary insufficiency.

What are the precautions for Luteinizing Hormone (LH)?

1. Some drugs that increase the LH value include Clomiphene, anticonvulsant, and spironolactone.
2. A few drugs decrease the LH, estrogen level, Testosterone, Progesterone, oral contraceptives, Digoxin, and Phenothiazine.
3. Patients with HCG-producing tumors and Hypothyroidism may give a false increased level.
4. Avoid lipemic, hemolyzed, or icteric serum.

How will you discuss the pathophysiology of Luteinizing Hormone (LH)?

1. LH and FSH are glycoproteins produced in the anterior pituitary gland.
2. The placenta also produces the LH hormone.
3. LH has a half-life of one hour.
4. LH release is stimulated by the gonadotropin-releasing hormone (GTRH).
5. Because of the feedback mechanism, estrogen and testosterone inhibit the production of LH and FSH.
6. LH production is suppressed during the luteal phase by negative feedback from the progesterone combined with estradiol, but a low level of LH is necessary for prolonged corpus luteum function.
   1. LH and FSH hormones act on the ovary and testes and are called gonadotropins.

7. GTRH (gonadotropins-releasing hormone) is stimulated by a low estrogen level in females and testosterone in males.
   1. The hypothalamus produces GTRH.
8. Both hormones (LH and FSH) acting on the ovary and testes:
   1. In females, FSH stimulates the development of follicles in the ovary.
   2. LH stimulates estrogen production from the follicle.
   3. LH stimulates testosterone from the Leydig cells.
9. Gonadal function tests are used for:
   1. In males: Hypogonadism.
   2. In females:
      1. Menstrual disorders.
      2. Fertility problems.
      3. Hirsutism or virilization.
10. LH stimulates in the female follicular (ovary) production of:
    1. Estrogen.
    2. Ovulation.
    3. Formation of corpus luteum cyst.
11. LH in males stimulates Leydig cells to produce testosterone.
12. LH has a role in the menstrual cycle, giving midcycle surge.
13. LH stimulates the corpus luteum formation, which supports an embryo in case of fertilization.

How will you discuss the Menstrual cycle?

1. The hypothalamus produces GTRH, which acts on the anterior pituitary glands, which produce LH and FSH.
2. There are cyclical hormonal changes in the ovary and the uterus.
3. Changes in the ovary are:
   1. Follicular maturation.
   2. Ovulation.
   3. Formation of corpus luteum.
4. Changes in the uterus are:
   1. Preparation of the endometrium for the implantation of the ovum.
   2. The vagina and cervix are prepared to allow the transfer of sperm.

5. FSH is needed for the maturation of the ovary and testes.
   1. FSH helps in the development of the follicles in the ovary.
   2. FSH stimulates the Sertoli cells in the male.
6. LH and FSH are important for the production of sperm.
   1. LH is necessary for ovulation and corpus luteum formation.
   2. LH is secreted in a variable amount each day, so one value will not indicate the actual body hormone level.
      1. So several samples are taken, these are pooled, or all the samples are tested for LH.
   3. A raised level of LH and FSH indicates primary gonadal failure like a polycystic ovary or menopause.
      1. In gonadal failure due to the pituitary gland, LH and FSH levels are low.

What is the Spot urine test, and what is its significance?

1. Spot urine test to detect LH surge is used to evaluate and treat infertility.
   1. This indicates the period when women are most fertile.
   2. LH surge precedes 24 hours of ovulation and can be recognized easily.
   3. A urine 24-hour sample is a better choice to avoid this variable amount of secretion of LH.
   4. LH assay can give a better idea of ovulation. There will be a surge in the LH level.
      1. The best sample is from 11 am to 3 pm.
2. LH surge gives a peak fertility period, which is due to ovulation.
   1. LH surge is between 12 to 16 days of the cycle.
   2. This surge can be found by taking a daily sample near the midcycle.

What are the normal values of Luteinizing Hormone (LH)?

Source 1

Source 2

• Lab values may vary from different labs and different methodologies.

What are the causes of increased Luteinizing Hormone (LH)?

1. A gonadal failure like:
   1. Menopause.
   2. Ovarian dysgenesis. (Turner syndrome).
   3. Testicular dysgenesis (Klinefelter syndrome).
2. Precocious puberty.
3. Pituitary adenoma.
4. The raised level of both  LH and FSH is seen in:
   1. Gonadal failure.
   2. Polycystic ovary.
   3. During menopause.

What are the causes of decreased values of Luteinizing Hormone (LH)?

1. Pituitary failure. Both LH/ FSH are low.
2. Hypothalamic failure will also lead to low LH and FSH levels.
3. Stress.
4. Anorexia nervosa.
5. Malnutrition.
6. In secondary gonadal failure, the LH and FSH levels are low.

How will we find the abnormality in the Lutenizing hormone (LH)?

Serum Luteinizing hormone (LH):

1. LH is secreted following intermittent stimulation of the pituitary gland by the GnRH.
2. So, a single value is not diagnostic of any disease.
3. It is suggested to take multiple samples.
   1. Collect 4 samples, each at 20-minute intervals.
   2. Pool the serum and then get the average value.
4. FSH and testosterone have stable values in females.

Urine Lutenizing hormone (LH):

1. As compared to serum LH, urine LH estimation is more difficult.
2. Urine LH needs a 24-hour urine sample.
3. There is the possibility that the artifact is due to dilution or concentration of the urine.
4. One advantage is to get an average 24-hour sample, which will avoid the serum pulsatile phenomenon.
5. Another advantage of urine LH is that it helps to get an idea about ovulation.
   1. LH surge precedes about 24 to 36 hours before ovulation.
   2. Collect the urine for LH test, starting 9 to 10 days after the menstruation.
   3. The best time to get the urine sample is between 11 AM and 3 PM because the LH surge in the blood takes place between 5 AM and 9 AM.
      1. The morning sample shows 56% positivity.
      2. The midday sample shows 94% positivity.
      3. The evening sample shows 88% positivity.

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