Ovulation test strips clinically detect luteinizing hormone in the urine. When the luteinizing hormone in the urine reaches its peak and is detected by an ovulation test, a strong positive result, i.e., a darker color, is seen, which indicates that ovulation will occur in about 24-48 hours. Subsequently, the luteinizing hormone value decreases and the color becomes lighter when tested with ovulation test strips. The main clinical reason for this is a decrease in the concentration of luteinizing hormone, which causes the test paper to become lighter. If you are planning to get pregnant, it is recommended to have intercourse 24 hours after the color of the test paper has darkened, which clinically improves the chances of getting pregnant.