Moondance, its is very possible that you can be pregnant and be negative on your HPT. My best friend was 12 weeks pregnant before she confirmed at the doctors that she was pregnant - she had PCOS, and all her HPT were negative - she did about 6 or 7 over a 8 week period. It wasn't until she got a blood test at the doctors that she found out that she was pregnant.

This is because you're kidneys actually break down some of the hcg (which is the hormone that is released when your are pregnant). Depending on the individual, depends on how much and how quickly your body breaks down the hcg. I would never be happy with a negative HPT if my period was late - you should really go get a blood test - there's no need for a quanitivative (how much hcg) unless your having a miscarriage. A qualitative (pos or neg) is sufficient.