LH and FSH test: why they're tested together and what the ratio means

LH and FSH are two hormones from the pituitary gland that work together to run the menstrual cycle. Labs usually look at them side by side because one is easier to read when you can see the other.

FSH and LH

FSH and LH on one order.

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Price checked October 2026. Not available in ND, RI, NY, NJ, MD and HI. We earn a commission on sales.

Why the two are tested together

MedlinePlus says an FSH test is often used with a blood test for LH, because these two hormones work together to control sexual development and reproduction. It also says a clinician interprets an LH result alongside FSH, and an FSH result alongside LH.

The pair is used for questions such as:

• fertility problems
• irregular or stopped periods in women of childbearing age
• whether menopause or perimenopause may have begun
• suspected pituitary or hypothalamus disorders
• early or late puberty in children and teens

A hospital lab guide from the UK (Gloucestershire NHS) lists fertility problems, menstrual irregularities in younger women, suspected pituitary disorders, and delayed or precocious puberty as the usual reasons.

Learn about each on its own page: what is FSH and what is LH.

What the LH:FSH ratio is

The ratio is LH divided by FSH. The same NHS lab guide says LH:FSH ratios are often raised (above 2.5) in samples collected on days 1 to 5 of the cycle in women with PCOS, but can be normal. It says PCOS can be diagnosed if two of three criteria hold and other causes have been excluded: infrequent or absent ovulation, clinical or biochemical signs of excess androgens, and polycystic ovaries on ultrasound. The ratio isn’t one of the three.

So a raised ratio isn’t a diagnosis, and a normal one doesn’t rule PCOS out. If PCOS is your question, start with the PCOS tests page.

Menopause questions

The NHS lab guide says LH and FSH are not routinely recommended for diagnosing menopause, and that for women over 45 with typical symptoms the diagnosis is clinical. It also says FSH is of no value in women taking combined oestrogen and progestogen contraception or high dose progestogen. See the perimenopause test page for the full guidance.

Reference ranges

Both tables are from the Oregon Health & Science University (OHSU) laboratory listings, in mIU/mL, copied as published. The phase names differ between the two listings, so each is shown separately.

FSH

Female	Reference range (mIU/mL)
Follicular Phase	4 to 12
Ovulation Phase	5 to 22
Luteal Phase	2 to 8
Postmenopausal	26 to 135

Source: Follicle Stimulating Hormone, Serum, OHSU.

LH

Adult female	Reference range (mIU/mL)
Follicular	2.1 to 10.9
Midcycle	19.2 to 103.0
Luteal	1.2 to 12.9
Postmenopausal	10.9 to 58.6

Source: Luteinizing Hormone, OHSU.

The listings give no further notes. Labs differ, so use the range printed on your own report. More on FSH is on the FSH levels page.

Preparing and timing

MedlinePlus says that if you have periods, you may need to be tested at a specific time in your cycle, because FSH levels change throughout the month. The NHS lab guide asks requesters to give the day of the cycle with the sample. MedlinePlus says to tell your provider everything you take before an LH test. The cycle timing tool and cycle timing guide cover timing.

The seller’s page for the FSH and LH test says the order measures FSH and LH only, and does not include estrogen, progesterone or testosterone. It says fasting isn’t required, gives no cycle-day instruction, and says results appear in an online account within one to three business days. Follow your clinician’s order for the cycle day.

One test or two

If only one hormone answers your question, a single-hormone test costs less. If you want both numbers, the pair on one order is the match.

• FSH onlyFSH only $49 See this test at HealthLabs
• LHLH only $49 See this test at HealthLabs

Sold by HealthLabs. Prices checked October 2026. Not available in ND, RI, NY, NJ, MD and HI. We earn a commission on sales.

What the test can’t tell you

Neither number nor their ratio gives a diagnosis alone. A clinician reads them with your age, symptoms, cycle and other hormones. See one if your periods are irregular or have stopped, if you are trying to conceive without success, or if you might be pregnant.