Women's Health
Luteinising hormone
Luteinising hormone (LH) is a gonadotrophin released by the anterior pituitary gland that triggers ovulation in women and stimulates testosterone production in men. At or near the patient it is measured mainly to detect the mid-cycle LH surge for ovulation timing and to support assessment of menstrual irregularity and gonadal function.
Why it is measured
Identifying the LH surge helps time conception, while the LH pattern supports the work-up of menstrual disorders, suspected menopause and disorders of puberty. It is most informative when interpreted alongside FSH, oestradiol and the clinical picture rather than in isolation.
| Typical range | Indicative adult values, which vary by method and assay: women follicular phase about 2 to 12 IU/L, mid-cycle ovulatory surge about 14 to 100 IU/L, luteal phase about 1 to 13 IU/L, and postmenopausal about 11 to 40 IU/L; adult men about 1.5 to 9 IU/L. Quantitative urine fertility monitors report LH in mIU/mL (numerically equivalent to IU/L) and typically flag a surge several units above each user's own baseline. Always apply the reference values quoted by the issuing laboratory or device. |
|---|---|
| Sample | Serum or plasma for clinic cartridge analysers; capillary or venous whole blood on some fluorescence-immunoassay systems; first-morning or timed urine for quantitative fertility monitors. |
| Turnaround | Typically about 3 to 15 minutes for point-of-care fluorescence cartridges and digital urine readers. |
Point of care devices that report it
- Wondfo Finecare LH Rapid Quantitative Test (Finecare FIA Meter Plus)
- Fluorecare LH (Luteinizing Hormone) fluorescence immunoassay
- Mira Fertility Monitor (quantitative urinary LH)
- Inito Fertility Monitor (quantitative urinary LH, E3G, FSH and PdG)
- Clearblue Digital and Connected Ovulation Test (qualitative urinary LH surge)
Questions, answered
Does a point-of-care LH result replace a laboratory LH assay?
Point-of-care LH gives rapid, near-patient values that are useful for screening or for timing ovulation, but calibration and methods differ between devices and accredited laboratories, so numeric results are not always interchangeable. Borderline or diagnostically important cases are usually confirmed by a laboratory assay and interpreted together with FSH and oestradiol. This is general information and not a substitute for clinical assessment.
Why is LH usually measured together with FSH and oestradiol?
These hormones operate as a feedback loop, so the relationship between LH, FSH and oestradiol is generally more informative than LH alone. The pattern helps distinguish ovulatory timing, menopausal change and pituitary from ovarian causes, which is why panels often report them together.
Is a urinary LH result the same as a blood LH result?
Urine monitors estimate LH excreted in urine to flag the ovulation surge, whereas serum assays measure LH circulating in blood. Both can detect the surge, but the units and absolute values are not directly comparable, and sample timing and hydration can affect urinary readings.