i had a faint bfp at 8dpo on Asda brand then tested negative with first responce, iv used them each time i fell pregnant (three times) and not once did they show posative for me 
then i used a CB digi and convinced myslef i wasnt as it said "not pregnant" but really i knew i was. i took another asda test and was DARK then got a neg blood test 
a week later my hcg numbers were at 3008 on beta blood test hehe. that was a lovely surprise as i ahd no idea with all the neg pos neg pos 
Good luck hun all the best xx
then i used a CB digi and convinced myslef i wasnt as it said "not pregnant" but really i knew i was. i took another asda test and was DARK then got a neg blood test a week later my hcg numbers were at 3008 on beta blood test hehe. that was a lovely surprise as i ahd no idea with all the neg pos neg pos Good luck hun all the best xx