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Luteinizing hormone (LH)

Hormones & Fertility · also called Lutropin, ICSH

What it measures

LH is a pituitary hormone that triggers ovulation and stimulates testosterone production. It is measured to investigate infertility, PCOS, menstrual irregularity, and delayed or early puberty.

Specimen and preparation

Specimen: Serum or lithium-heparin plasma
Tube: Gold top
Preparation: Day 2–5 of the cycle for baseline; urine LH kits detect the ovulation surge.

Reference range

Group	Range
Female, follicular phase	2.4–12.6 IU/L
Female, mid-cycle peak	14–96 IU/L
Postmenopausal	7.7–59 IU/L
Adult male	1.7–8.6 IU/L

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

Menopause and primary ovarian failure
Polycystic ovary syndrome (raised LH:FSH ratio)
Primary testicular failure
Precocious puberty (central)

Causes of low values

Hypothalamic or pituitary disease
Hyperprolactinaemia
Anabolic steroid use
Hormonal contraception

Method

Chemiluminescent immunoassay

Good to know

LH is secreted in pulses, so single values can vary.

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