The Inverness Medical Ovulation Test Kits help you plan your pregnancy. The kit gives you five ovulation predictor sticks to help you predict your most fertile 24 hours of the month. The tests quickly and accurately detect the increase in luteinizing hormone in your urine (LH Surge), which normally occurs 24 to 48 hours before ovulation. You are most likely to become pregnant if you have intercourse within 48 hours after you detect your LH surge.