My lmp was on March 25, 2012. I normally have a 30-31 day period I am now on day 33 April 26, 2012 so 2-3 days late. My husband and I started trying to conceive our second child this month. I am normally right on time have a period each month. I have taken two HPT and both negative. My job is stressful and I have just recently in the past three weeks stopped taking Phentermine to lose weight and also had liposuction done 4 weeks ago. So I think that all that may have messed up my period. But I've had all the symptoms. The food cravings, extreme fatigue, sore boobs, excessive vaginal d/c, nausea, vomiting, moodiness, cramping, sensitive to smells, stuffy runny nose & sore throat, and elevated bbt for 16 days now. But still no positive HPT. I am going to get my blood drawn tomorrow. So I guess my question is How early can pregnancy be detected by a blood test? Any suggestions would be much appreciated.

It should be effective at this point.

Some women will have a positive result on a blood test as early as about 8 days or so after ovulation. It will depend on when implantation occurs which can vary slightly. Most will have an accurate result once a period is missed. The exception could be a late ovulation in which several more days would be necessary. This would not be common however.