Ovulation Test Strips help you predict the time of ovulation and peak fertility. It is during the fertile time that pregnancy is most likely to occur. All you have to do is pee on a stick or strip (or pee in a cup and dip the stick or strip into the cup) and wait a few minutes for the indicator to appear. If the test line shows up darker than the control line, you're about to ovulate. (There are always low levels of LH in your body, so if the test line shows up but appears lighter or fainter than the control line, you're not ovulating yet.)