Conception date due to ultrasound at 11w4days on 1/20/14 was around 11/16/13, had a negative hcg qualitative 11/26/14. can blood qual test be wrong?

Not wrong: If you got pregnant around 11.16.13 +/- a few days then it makes sense that your bhcg would not have been positive quite yet around that time. Why does it matter though? The sonogram gives you a very accurate conception date so worry about the blood test is not likely to be fruitful.

Yes: Lab errors do occur, so definitely within the realm of possibility. Seemingly your HCG should have been positive 10 days following conception. It's possible that conception actually occurred a few days later, but even accounting for that, HCG would seemingly be positive. Bottom line, most important for dating pregnancy is first trimester us, which you've had!

Date: If you had an ultrasound at 1/2014 that shows you are 11 weeks 4 days you are just that around 11 weeks pregnant. When you get pregnant there can be 3 or 4 days before you have a positive hcg. So it is possible that you still could have had a quantitative HCG that was negative on 11/26/13. You have to remember that ultarsound gives dates based on data from general population. It is not exact.