How soon can a sonogram detect ectopic pregnancy ? i'm 3 days late with positive test. last period april 1.

Another week or two: You'd be 5 weeks counting from your last period. Pretty early to see the pregnancy in either the tube or the uterus. Have you had previous ectopics? See your provider. A good plan is to get pregnancy hormone blood tests drawn every few days then an ultrasound in a week or so. It's good that you are seeking medical care early.