From the Guidelines
Luteinizing hormone (LH) levels should be interpreted in the context of the clinical presentation, with abnormal findings defined as LH >11 IU/l, LH <7 IU/ml, or an LH/FSH ratio >2, according to the study published in the Journal of Neurology, Neurosurgery and Psychiatry 1. When evaluating LH levels, it is essential to consider the patient's symptoms, menstrual cycle phase, and other hormone levels, such as FSH, estradiol, and progesterone.
- Normal LH levels vary by age, sex, and menstrual cycle phase, with adult females typically having 2-15 IU/L (higher during ovulation) and adult males 2-9 IU/L.
- Elevated LH can indicate primary gonadal failure (menopause, primary ovarian insufficiency, or testicular failure), polycystic ovary syndrome (PCOS), or precocious puberty, as suggested by the study 1.
- Low LH may suggest hypothalamic-pituitary dysfunction, such as hypogonadotropic hypogonadism, hyperprolactinemia, or functional hypothalamic amenorrhea.
- For fertility assessment, LH should be measured alongside FSH, estradiol, and progesterone, with the LH/FSH ratio being particularly important (ratios >2:1 suggest PCOS) 1.
- Timing is crucial for accurate interpretation - in women, LH is best measured during the early follicular phase (days 2-5 of the menstrual cycle) for baseline levels or during mid-cycle to confirm ovulation.
- The study also highlights the importance of considering other hormones, such as prolactin, testosterone, and androstenedione, in the evaluation of reproductive endocrine disorders 1.
- It is also important to note that PCOS is a common cause of irregular periods in women and should not be confused with isolated polycystic ovaries, as discussed in the study 1.
From the FDA Drug Label
In humans, subcutaneous administration of single daily doses of leuprolide acetate results in an initial increase in circulating levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH), leading to a transient increase in levels of the gonadal steroids However, continuous daily administration of leuprolide acetate results in decreased levels of LH and FSH.
The interpretation of LH levels in the context of leuprolide acetate administration involves considering the initial increase in LH levels due to the drug's agonist effect, followed by a decrease in LH levels with continuous administration, indicating suppression of gonadotropin secretion.
- Initial LH increase: Expected as a result of the initial stimulation by leuprolide acetate.
- Decreased LH levels: Indicative of the suppression of gonadotropin secretion with continuous leuprolide acetate administration, which is the desired therapeutic effect in conditions like prostatic cancer. 2
From the Research
Interpreting LH
To interpret LH (luteinizing hormone) levels, it's essential to consider the context of the test results.
- LH is a hormone that plays a crucial role in ovulation and fertility, and its levels can be affected by various factors, including age, sex, and medical conditions 3.
- In women, LH levels typically surge before ovulation, triggering the release of an egg from the ovary 4.
- In men, LH stimulates the production of testosterone, which is essential for sperm production and fertility 5, 6.
- When interpreting LH test results, it's essential to consider the reference interval or range provided by the laboratory, as well as the individual's medical history and physiological condition 7.
- For example, a low LH level may indicate hypogonadotropic hypogonadism, a condition characterized by low sex hormone production, while a high LH level may indicate polycystic ovary syndrome (PCOS) or other conditions 4, 5.
- Additionally, LH levels can be influenced by various medications, including clomiphene citrate, which is used to treat infertility and hypogonadism 6.
- To accurately interpret LH test results, healthcare providers must consider the individual's overall clinical picture, including their medical history, physical examination, and other laboratory test results 7.