There was an interesting discussion I remember seeing on a pregnancy forum a while back about something called "the hook effect." Basically it's the idea that HCG can get high enough for a home pregnancy test to be negative?!?!?! Depending on the test this can happen when HCG is anywhere from 400,000 to 1,000,000 - which is not typical in standard pregnancies but can happen with multiples or with molar pregnancies. But once HCG starts to get up into it's peak even in a standard pregnancy, pregnancy tests can have trouble detecting HCG. The theory is that the HCG is so concentrated that test antibodies are unable to hook to the HCG to bind it. (Google it for the much more scientific explanation.) Crazy, right? How do you prove the hook effect? Dilute the sample and retest - if the test gets darker upon dilution, then you have proven the hook effect. I thought this was all fascinating when I read about it, but 1) wasn't pregnant to try it out and 2) and even if I was, there usually aren't just extra pregnancy tests around my house.
Then, I was cleaning out the bathroom this weekend and found a 3 pack of pregnancy tests (that I had obviously forgotten about or they would have been used a long time ago) and they were about to expire. So I thought I'd do my own little science experiment. The only thing that would make this more interesting would be if I knew my actual HCG levels right now. I don't. The last time they were reported to me they were over 36,000. They should be well above that now.
Pretty fascinating, huh? My undiluted urine is producing a barely positive result. Add some water and the test line gets darker. Add even more water and the test line gets even darker.
Like I said, nothing of true substance in this post, other than proving that I'm a nerd, but I think it's cool. :)
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.