David ovulation test paper to monitor ovulation is more accurate, but it is best to follow the instructions for correct use, which can improve the accuracy of ovulation test paper. When using ovulation test paper and monitoring ovulation, it is best to use morning urine, where the concentration of luteinizing hormone in urine is higher. If it is not morning urine, the concentration of luteinizing hormone in the urine will be reduced after the urine is diluted, and it will cause false negative ovulation test strips. When using ovulation test strips, you also need to look at the factory date, if the ovulation test strips are out of date, it will also cause false negative. It is best to use ovulation test strips about 14 days before the onset of menstruation. The increase in luteinizing hormone levels in the body during ovulation will cause the ovulation test strips to appear positive. The luteinizing hormone level peaks at the time of ovulation, which will cause a strong positive ovulation test. Within 24 hours after a strong positive test, you can ovulate, and if you plan to get pregnant, you need to arrange intercourse in time.