The way ovulation predictor kits work is that they have a substance in them that will detect when the LH surge is occurring and cause the activation of a chemical reaction on the side of positivity. For some kits that is a smiley face, and on others it is a + sign.
In general, true ovulation occurs approximately twenty-four hours after the LH surge.
The way to predict when you approximately ovulate is to subtract fourteen from the generalized length of your menstrual cycle. Meaning that if your periods occur every twenty-eight days then you probably ovulate around day fourteen. If they occur every forty-two days then you probably don’t ovulate until around day twenty-eight.
Start testing with the ovulation predictor kit approximately four days prior to suspected ovulation.
Use the test sticks on the second urination of the day. The first urination may be too concentrated and produce inaccurate results.
Have intercourse approximately every other day during the fertile period, however, do not have intercourse on the day the kit turns positive wait until the next day for better timing.
If you are unsure as to whether or not the kit detects the surge then you can continue to test however, be aware that it may be positive for several days after ovulation due to the fact that the LH is still elevated. The most accurate positive is the first one.
HCG shots can cause a positive LH to be detected on the kits so if you have taken a HCG shot then do not continue to use OPKs.