how soon after O can I take blood test?

[Anonymous]

Been TTC for about 7 mos now, and I have lab sheets at the ready for me to get a blood test whenever I want. I am charting temps and clearly O'd about a week ago. OB says I can get the blood test a week after O, but I'm confused - if implantation takes 6-10 days, would a blood test be positive even before implantation? On the other hand, of course I'm eager to get a test asap, but I'm sick of negative tests and would just end up going back later to make sure.... I was proposing to wait 14 days after O (I'm on prometrium which is delaying my cycles, so really the blood tests are so I can know to stop the prometrium if I'm not pregnant), but my OB and my accupuncturist both say that's overkill. What do you think?

[Anonymous]

I think 14dpo is reasonable. My RE always scheduled them at 14 or 15dpo. Waiting until 14dpo is certainly not "overkill."

I personally think one week past ovulation is too early. You will get a negative result if implanation has not occurred yet. Why torment yourself with all that, wondering if the negative really means negative, or if you get a really low number, wondering if it's because you had it done so early? I'd just wait until 14dpo and then you will know the result is accurate one way or the other.

Of course, nothing stops you from testing on your own at home too, but as far as beta testing, I'd wait until 14dpo.

Curious what others think.

[Anonymous]

I think at 12 dpo you should get an accurate result through the blood test - this way you give a chance for an embryo to implant, so the results at that point will be reliable.

[Anonymous]

I got a + on an hpt at 9dpo and confirmed it with blood test at 12dpo.
I would do it at 12dpo I think.

[Anonymous]

The only thing about doing it at 12dpo is that, if it's positive, you are likely to get a fairly low number. A low number would be normal for 12dpo, but low betas can also indicate a chemical pregnancy. For me, since I have had chemical pregnancies before, I would be worried/wondering which it is. Personally I'd rather start using urine tests at home around 10dpo and see if the lines are getting darker each day (using FMU), and then go for a beta several days later.

At 14dpo, you can infer a bit more from the beta - extremely low would be cause for concern, but over 100 would be a good sign. I know it's not the initial number but the doubing that really counts, but I think a lot of people worry themselves more than they should with very early testing. Not saying I'm not guilty of that also, and I know everyone's need for info is different, but just pointing out that the norm, even with REs, is to wait until about 14-15dpo.

[Anonymous]

Why don't you use a HPT before going for the blood test. Wait until you get a positive HPT before you go for a blood test. If you hit 12-14 DPO w/o a positive HPT then get the blood test if you really want to, but know it is probably going to be negative.

[Anonymous]

I got a blood test at 12dpo and got a positive but the number was low so my ob wanted me to retest again anyway. I would wait until 14dpo.