How to use ovulation (LH) tests

Ovulation tests (often called OPKs) look for the LH surge – the hormone spike that tells your ovary “release the egg!”. A positive usually means ovulation is coming within about 36 hours, which makes them handy for planning.

Step by step

1. Work out when to start. Cleveland Clinic suggests around day 10 of a typical cycle; with longer cycles, start a few days later.
2. Test at roughly the same time each day and read your test’s leaflet for its preferred time.
3. Try not to drink loads right before testing – very diluted pee can make the line fainter.
4. Read the result in the time window the leaflet gives. A test line as dark as (or darker than) the control line usually counts as positive.
5. Keep testing daily until you get a positive, then log it in the app.

When tests get confusing

• Faint lines on most days are normal – there’s always a little LH around.
• Some people with PCOS can have high LH levels much of the time, giving lots of positives.
• A positive shows the surge, not proof that an egg was released. A temperature rise afterwards helps confirm it.
• Some medications and recent pregnancy can affect results – check the leaflet.