HCG test question

[animekoneko17]

I have a question about HCG and implantation. I read somewhere that it takes approximately 1 week (7 days) for implantation to take place. HCG doubles ever 2-3 days. So if you're at 1 mlu/ml @ dpo 7 (implantation) then dpo 9 you will be at 2 mlu/ml, then dpo 11 you will be at 4 mlu/ml, then dpo 13- 8 mlu/ml. Thats assuming bean implanted on dpo 7 of the dpo 6-12 possible and it only takes 2 days to dbl, if it took 3 to dbl at dpo 13 you would be @ 4 mlu/ml.

How can a test that reads 25 mlu/ml be 99% accurate on dpo 14?

I'm at 14 dpo, nauseous, tender breasts, fatigued for the last week and my bbt is staying high (it's never done that not even while pg with dd. I'm not sick and the test keeps coming up . So I'm curious, any insight is welcomed.

 

[lisap2008]

Because with most pregnancies HCG doubles much faster then that. plus most 25mlu tests do pick up on lower levels , I have seen wondfo internet strips pick up a faint positive with a HCG level of 5.

 

[Weebles]

That's exactly why you're not out until AF shows. But to hopefully answer your question your starting hcg level is more of a range. When I try to figure out when I should test I use a starting level of 5. I think the accuracy of tests assumes implantation on 6dpo with a 14 day leutal phase and probably levels doubling every 48 hours. Any difference changes when you can get a BFP.. It's also why doctors usually recommend waiting until AF is truly late.