Also, tumors in the reproductive system might give false readings when a woman seeks pregnancy tests. (giantmommy.com)
While ovulation kits can be highly accurate, there are some factors that can cause false readings. (checkpregnancy.com)
But these tests aren't always 100 percent accurate, and there have been several instances when a breath test provided false readings and the accused driver actually wasn't impaired at all. (nrlawyers.com)