Q: At what time of the day should I test with my OPK (ovulation predictor kit)?

A: In general, it's suggested to test in the early afternoon, usually between 12 and 5 PM, within a couple of hours before or after 3 p.m. or so. Many women can have an LH surge after waking up, but it can take four to six hours for the LH surge to first show up in the urine. You should preferably test around the same time of the day, and because the LH surge is sometimes only detected for less than 24 hours, there are many women who test twice a day, just to make sure they don't miss the very first surge.