What are OPKs?
OPKs (Ovulation Predictor Kits) are also known as ovulation test strips. They are urine-based test strips that you use at home to detect ovulation measuring the hormone LH (luteinizing hormone).
Your tests can look two different ways they can either be test strips which you need to urinate in a cup and carefully dip the stick into the test or they may look more like a pregnancy test and you urinate on the extended tip.
How does an OPK work?
As I said OPKs detect the LH hormone in your urine. When ovulation is near it spikes in order to get the egg in its final stage of maturity. About 1.5 days after the LH surge ovulation occurs. That means to increase your chances of conceiving that cycle you should have baby-making sex as soon as you get the positive OPK and for 2 days after the positive OPK.
How exactly do you use an Ovulation Kit?
Be sure to read all of the instructions of the kit you get. They seem to always vary just a bit.
Generally, a kit comes with 5-10 OPK tests. About 2 days before you think you will be ovulation you should take your first test. If you are unsure use this ovulation calculator or you can use a fertility app we use Clue (apple and android). If you are irregular you should test from the earliest day you may ovulate until you get your positive OPK.
OPKs just like pregnancy tests have two lines one is a control and then there is the test line, But unlike pregnancy tests, the OPK test line needs to be just as dark or darker for it to be positive.