LH (luteinising hormone) blood test
Quick answer: An LH test measures luteinising hormone, a hormone from the pituitary gland that triggers ovulation in women and testosterone production in men. It is ordered for irregular periods, suspected PCOS, infertility, early or late puberty and menopause questions, and for low testosterone in men.
- SampleBlood
- TakesAbout 5 minutes
- Before the testWomen may be asked to give the sample on a particular day of the cycle, often day 2 or 3; follow your doctor's timing.
- In fertility careLH is checked with FSH as part of a fertility work-up, and its surge is what ovulation tests and trigger timing in IVF are based on.
How the test is done
- 1Staff note the day of your cycle if you are a woman
- 2Your arm is cleaned and a needle is placed in a vein
- 3Blood is collected, often in the same tube used for FSH and estradiol
- 4A plaster is applied and you can leave
What your results can mean
Reading your report
LH levels change through the menstrual cycle and with age, so results depend on the day the sample was taken; discuss them with your doctor.
If the result is outside the usual range
A high LH can be seen with PCOS, around ovulation, after menopause or when the ovaries or testes are not working well. A low LH can be seen with problems in the pituitary or hypothalamus, very low body weight, heavy exercise or some hormone medicines.
Who usually has this test
Women with irregular periods, suspected PCOS or difficulty getting pregnant, men with low testosterone or low sperm count, and children with early or delayed puberty.
Risks and aftercare
There is no special aftercare, and you can carry on with your day.
Names and options
Also called: LH, luteinizing hormone, LH hormone test
Listed by the hospital as
- LH (LEUTINISING HORMONE), SERUM
Where this test fits in fertility care
- 1Fertility work-upThis test
- 2Screening before IVF or IUI
- 3During treatment
- 4After embryo transfer
- 5Pregnancy check-ups
- 6If treatment has not worked
The usual order. See every test at each stage →
Questions about this test
When should an LH blood test be done?
For a baseline fertility check, women are usually tested on day 2 or 3 of the period, often with FSH and estradiol. To catch the LH surge, testing is done around the middle of the cycle. Your doctor will tell you which day suits your situation.
What does a high LH to FSH ratio mean?
An LH level higher than FSH is seen in some women with PCOS, but it is not used on its own to diagnose PCOS. Doctors combine it with your periods, scan and other hormone results.
Is an LH blood test the same as a home ovulation test?
Both look at LH, but a home ovulation kit detects the LH surge in urine, while a blood test measures the exact level at that moment. Blood tests are used for fertility work-ups, and urine kits help time sex around ovulation.
Related tests
Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
Get directions ↗IVF Pulse fertility care at Tamara Hospital →
Reception
Waiting area
IVF lab
This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.