could is the operative word there. You could. But it would be pointless. If what you want to ask is, could a pregnancy test be positive 15 days after your LMP, the answer is no. Unless your LMP was not really a period at all, but just breakthrough bleeding, which does happen. Was your period shorter and lighter than usual? If not, testing now would be truly pointless.
The first day of your period is Cycle Day 1. From that point, an egg (or several) will begin to mature. Once fully matured, a burst of estrogen will cause it to be released. This typically occurs midway through your cycle if you have a standard 28 day cycle. The phase before ovulation is called the follicular phase. After ovulation is the luteal phase. The luteal phase is a set time period that is typically 10-14 days long. So you ovulate 10-14 days before you expect your period. Don't test until you are a week, or at least a few days, late.
at 5:39 PM on Dec. 13, 2010