False negatives can be caused by human error (not peeing on the test long enough) or test failure (using an expired test, test is stored in a bad place, etc.)
Also, for a test to show up positive, it has to detect pregnancy hormones in the urine. Once these hormones are detected, the test will read positive. That's what that second window is testing for. If there are no pregnancy hormones to detect, the test would not show up as a positive.
Well, if you check the result after a long time (much longer than the time indicated on the box), it might be a false positive. That's why the test has to be looked at after the time indicated and then _thrown away_ .
Posts: 127 | Registered: Nov 2001
| IP: Logged |
In my experience, if a home pregnancy test comes up positive twice (I always take it twice, the statistical probability of getting 2 false positives is so small, you would have a better chance at winning the lotto), go to a doctor cause you can retake it, and retake it, but it will keep reading positive. I took several when I was pregnant, cause I kept hoping for one test to be negative. It never happened. Anyhoo, that is my perspective on home pregnancy tests.
Posts: 234 | From: Ottawa, Ont, Canada | Registered: Mar 2002
| IP: Logged |
Copyright 1998, 2013 Heather Corinna/Scarleteen
Scarleteen.com: Providing comprehensive sex education online to teens and young adults worldwide since 1998
Information on this site is provided for educational purposes. It is not meant to and cannot substitute for advice or care provided by an in-person medical professional. The information contained herein is not meant to be used to diagnose or treat a health problem or disease, or for prescribing any medication. You should always consult your own healthcare provider if you have a health problem or medical condition.