How long before blood test will be positive?

[Annie Mac]

I had what might have been implantation bleeding yesterday. Because I was going to the doctor anyway, I told her about it and she ordered a blood hcg test for me. I was going to go and do that today, but will anything actually show up? If there was implantation yesterday (and here I'm assuming that implantation & bleeding happen more or less simultaneously, but I could be wrong), wouldn't it take at least a few days to show up in my blood? She also ordered another test one week following to see if it goes up, as another complicating factor is a miscarriage I had in November, so there could be some hcg still floating around in there (although I had a normal period afterwards, so probably not). 

I've googled like crazy and can't find definitive answers to my questions, which are:

1. how long after implantation does hcg show in the blood?

2. does bleeding & implantation occur at the same time, more or less? The blood is brown, so it's not new, maybe it takes a while to trickle out?

3. how long does hcg stay in the body following a loss (at 8 weeks)

4. do I have a better chance of a successful pregnancy if I actually felt the implantation? Like it's really stuck in there good? (Admittedly, this last question is probably unanswerable and is just me wanting to be reassured).

Thanks in advance.

[Tenk]

Hey Annie, very nice to see you again.  I hope all is going well?!

So after implantation/spotting you can have a small amount of hcg in your system within 24 hours.  It can be a small amount, but anything over 15 is considered positive.  With one of my children my first blood test was 11 and they ordered a 2nd because I *knew* I was pregnant and at 48 hours after that it was 42 maybe?!

This time I implanted on 8dpo and on 10dpo had a + HPT, didn't even do an hcg blood test for quants.  Good luck, I'm hoping for more good things from you!!

[Annie Mac]

Hi Tenk!

Yes, I am fine. I haven't been back to the DDC, just couldn't stand to look at it, so I don't know how you're doing? How ARE you doing? I didn't go get my test done today. I've decided to wait a few days so that there's something to measure. I could really just wait & see if I get my period, but there is other bloodwork to be done as well, that really should get done regardless of pregnancy status.I kinda wish it wasn't all lumped up together, because at this point I feel a bit superstitious and silly getting my hcg levels when I haven't even missed a period yet. I really don't feel pregnant or anything, and doubt I am. Still, my fingers are crossed.

So when you got your "11" result, how many days post-ovulation were you?