Hi there
thought i'd give my opinion, I think although theres loads of different tests, the early detection , digital ones, expensive, cheap etc etc, they are pretty much all the same accuracy wise.
I bought the cheapest test that I could find in the farmacy, a simple strip of card that u dip in a cup of pee, no boxes, screens or anything, and!!... I tested the day before I was due for my af, as I had a feeling I was pregnant.
I think in the end its simply due to your hcg levels, every womans different, so are the levels of hcg etc, some women never get a positive result with urine tests, if your levels are low even these so called early response tests wouldn't be able to pick up the hcg!!.
I've read alot of your posts, but I don't understand why you are wasting so much time and money on hpt tests, just get a blood test done!! (unless you've done one already) then u'll know for sure if u are or aren't pregnant, its stupid getting all stressed by not knowing what could be nothing, or could be something very important that if you are, you've got to start thinking bout changing your lifestyle, vits, visit to the docs etc etc.
Anyway thats my opinion, I hope that you are pregnant!! :d , at least all this stressing will be worth it :d , sending out loads and loads of baby dust your way!!!
Xxxx