Ovulation test strips are used to monitor ovulation, and can be used to roughly estimate follicular development and ovulation based on the dynamic changes in the ovulation test strips. If you have a regular 30-day menstrual cycle and start monitoring on the 10th day of your period, you can see that the ovulation test paper is negative, i.e., one red bar, to weakly positive, i.e., one dark and one light red bar, and then to strongly positive, i.e., two red bars. There are two red bars, that is, a strong positive, it is about to ovulate, there are two red bars after about 36 hours will ovulate, that is, from a strong positive to a weak positive when ovulation is going to occur, ovulation test paper is negative after ovulation will end. Ovulation test paper to monitor ovulation has a certain reference value, the standard of detection of ovulation is to do ultrasound, through the ultrasound can understand the follicle development, maturation and discharge.