I always believed in these ones. They always seemed to be the best and nailed it 8 days early on my first pregnancy. However, this time after purchasing 3 boxes of 3 tests.... and testing every to every other day till 4 days after my period, all were negative. My BBT was still high so I knew something was going on... but I was losing hope thinking I missed catching it again. Decided to buy other brands. 4.... YES. 4 boxes of other brands all no doubt about it positive 4 days late. Dollar store, clear blue, ept and a generic Walmart brand... all tested positive. So I took another first response. And it was Negative! I no longer trust that brand. So beware ladies! Trust your gut if you think you're preggo and try another brand!