Yes, as others have said 10 DPO is sort of the earliest you can reasonably test. But I am a POAS addict and often start testing at 8 DPO...
I had posted these stats in another thread, but I'll post them here too. They are from babymed.com. I don't know how valid the data is, but I love obsessing on this stuff:
Q: When can I expect my home pregnancy test (HPT) to be positive?
A: With most current pregnancy test kits (sensitivity 25 milli-international units per milliliter) hCG can be detected in the urine as early as 3-4 days after implantation (9-15 days after ovulation), though it sometimes can take longer. Here are the expected positive HPTs:
3 days before a missed period: 51% positive
2 days before a missed period: 62% positive
1 day before a missed period: 68% positive
Day of missed period: 74% positive
2-3 days after missed period: 88% positive
If you are pregnant, about one in two HPTs is expected to be positive 2-3 days before a missed period, and three in four HPTs are expected to be positive on the day you miss your period (JAMA 2001; 286:1759). A negative pregnancy test on the day of a missed period is normal in about one in four pregnancies, and within the next 4-5 days most will have become positive. A negative HPT result 10+ days after the missed period makes a pregnancy unlikely.
Updated: 1/5/2007 9:01:00 PM