FSH and LH (Gonadotrophin) Panel
The FSH and LH panel measures the two pituitary gonadotrophins together to assess the hypothalamic-pituitary-gonadal axis. Interpreted with gonadal steroids and cycle timing, the pattern localises reproductive dysfunction: elevated gonadotrophins with low steroids indicate primary gonadal failure, while low or inappropriately normal gonadotrophins indicate a central cause.
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Biomarkers
Blood (serum)
Sample
1–3 business days
Turnaround
No — however, collection timing relative to the menstrual cycle is essential and should be documented; ovarian reserve FSH is conventionally drawn in the early follicular phase (around day 3)
Fasting
What is the FSH + LH test?
The FSH and LH Panel measures the two pituitary gonadotrophins together, providing the central assessment of the hypothalamic-pituitary-gonadal axis. Measured as a pair, they localise the level of a reproductive disturbance and characterise ovarian, testicular, and pituitary function. Within reproductive endocrine assessment, FSH and LH are interpreted together and in relation to gonadal steroids (oestradiol or testosterone), cycle timing, and reproductive stage. The pattern is what matters: elevated gonadotrophins with low gonadal steroids indicate primary gonadal failure, including menopause and primary ovarian insufficiency, whereas low or inappropriately normal gonadotrophins with low steroids indicate a hypothalamic or pituitary (central) cause. The panel is used in subfertility evaluation, menopausal assessment, the workup of amenorrhoea, and the investigation of delayed or precocious puberty, and the LH-to-FSH ratio adds value in conditions such as polycystic ovary syndrome. Because secretion is pulsatile, single values are interpreted with awareness of fluctuation, and cycle timing is essential in menstruating women.
What does the FSH + LH test measure?
Follicle-stimulating hormone is a glycoprotein gonadotrophin secreted by the anterior pituitary under pulsatile hypothalamic GnRH control. In women it drives ovarian follicular development and, with LH, regulates the menstrual cycle; in men it supports Sertoli-cell function and spermatogenesis. Its secretion is modulated by negative feedback from gonadal steroids and inhibin, so FSH rises when gonadal function declines. FSH has a longer half-life than LH, making its levels somewhat more stable across the pulsatile cycle.
FSH is central to evaluating ovarian and testicular function and localising the level of a reproductive disturbance. An elevated FSH with low gonadal steroids indicates primary gonadal failure (including menopause), while a low or inappropriately normal FSH with low steroids points to a hypothalamic-pituitary cause. It is a key marker in subfertility assessment, menopausal evaluation, and the workup of delayed or precocious puberty.
Luteinising hormone is a glycoprotein gonadotrophin secreted by the anterior pituitary under pulsatile GnRH control. In women the mid-cycle LH surge triggers ovulation and supports the corpus luteum; in men LH stimulates testicular Leydig cells to produce testosterone. Because secretion is markedly pulsatile and the half-life short, single LH values fluctuate, and the LH-to-FSH ratio carries additional diagnostic information in some conditions.
LH complements FSH in localising reproductive dysfunction and in detecting the ovulatory surge. The LH-to-FSH ratio is informative in conditions such as polycystic ovary syndrome, where LH is often disproportionately elevated. As with FSH, an elevated LH indicates primary gonadal failure, while a low or inappropriately normal LH with low gonadal steroids suggests a central cause.
Why is the FSH + LH test ordered?
- Evaluation of subfertility in women, assessing ovarian reserve and ovulatory function alongside oestradiol and cycle timing
- Assessment of the menopausal transition or suspected primary ovarian insufficiency, where elevated gonadotrophins with low oestradiol are characteristic
- Workup of amenorrhoea or oligomenorrhoea to localise the disturbance to the ovary or the hypothalamic-pituitary axis
- Investigation of male hypogonadism, distinguishing primary testicular failure from a central cause alongside testosterone
- Evaluation of delayed or precocious puberty, interpreted with age- and stage-appropriate reference ranges
- Assessment of polycystic ovary syndrome, where the LH-to-FSH ratio is often informative
- Investigation of suspected pituitary or hypothalamic disease affecting gonadotrophin secretion
Sample collection and turnaround
Sample type
Blood (serum)
Fasting required
No — however, collection timing relative to the menstrual cycle is essential and should be documented; ovarian reserve FSH is conventionally drawn in the early follicular phase (around day 3)
Collection method
Venipuncture at patient service centre
Turnaround
1–3 business days
Collection notes
Document the cycle day, menopausal status, and any sex-hormone, contraceptive, or fertility therapy. For ovarian reserve assessment, draw FSH (with oestradiol) in the early follicular phase. Advise patients to withhold high-dose biotin supplementation for 48–72 hours prior to collection.
Specimen requirements
Minimum 0.5 mL serum. Separate serum from cells per LabCorp protocol. Specimen stable refrigerated; follow LabCorp transport guidelines.
What can affect FSH + LH results?
FSH and LH vary across the cycle, with a pronounced mid-cycle LH surge, so the cycle day must be documented. Ovarian reserve assessment by FSH is conventionally performed in the early follicular phase (around day 3).
Gonadotrophins, particularly LH, are secreted in pulses with a short half-life, so a single value can vary substantially within a short period; borderline results may need repeating or interpreting with the overall pattern.
Oestrogens, progestogens, and combined contraceptives suppress gonadotrophin secretion through negative feedback, lowering FSH and LH and obscuring the underlying axis. Hormone use must be documented.
GnRH agonists and antagonists and ovulation-induction agents directly alter gonadotrophin levels as part of treatment, so results during such therapy reflect the intervention rather than baseline axis function.
Biotin can interfere with streptavidin-biotin immunoassay platforms, producing falsely altered FSH or LH. Patients should withhold high-dose biotin for 48–72 hours before collection.
Pituitary disease, hypothalamic suppression, and elevated prolactin can lower gonadotrophin secretion, producing a central pattern of low gonadotrophins with low gonadal steroids.
What do FSH + LH results mean?
Elevated
Elevated FSH and LH with low gonadal steroids indicate primary gonadal failure — menopause or primary ovarian insufficiency in women, primary testicular failure in men. A disproportionately elevated LH relative to FSH may be seen in polycystic ovary syndrome. Postmenopausal gonadotrophins are physiologically high.
Normal
Gonadotrophins within the age-, sex-, and cycle-appropriate range, with normal gonadal steroids, suggest an intact hypothalamic-pituitary-gonadal axis. Interpretation always depends on cycle timing in menstruating women and on the concurrent gonadal steroid result.
Reduced
Low or inappropriately normal FSH and LH with low gonadal steroids indicate a hypothalamic or pituitary (central) cause of hypogonadism, such as pituitary disease, hyperprolactinaemia, or functional hypothalamic suppression. Suppression by exogenous sex hormones should be excluded.
Note: FSH and LH must be interpreted together, in relation to gonadal steroids, cycle timing, and reproductive stage — single values are uninterpretable without this context. Pulsatile secretion causes fluctuation, exogenous hormones suppress the axis, and the LH-to-FSH ratio adds information in conditions such as PCOS. The pattern of gonadotrophins and steroids, not any one value, localises the disturbance.
Frequently asked questions
It measures the two pituitary gonadotrophins together to assess the hypothalamic-pituitary-gonadal axis. Interpreted with gonadal steroids and cycle timing, the pattern localises reproductive dysfunction to the gonad or the central axis.
How to access the FSH + LH test
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Published: June 2, 2026
Last reviewed: June 2, 2026
- Practice Committee of the American Society for Reproductive Medicine. Diagnostic evaluation of the infertile female: a committee opinion. Fertil Steril. (2015)
- Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. (2018)
- Practice Committee of the American Society for Reproductive Medicine. Testing and interpreting measures of ovarian reserve: a committee opinion. Fertil Steril. (2020)
- Santoro N, Randolph JF. Reproductive hormones and the menopause transition. Obstet Gynecol Clin North Am. (2011)
This content is for licensed healthcare practitioners only and does not constitute medical advice. Clinical decisions should be based on the full clinical picture and not on any single test result.
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