At what level of Beta-hCG is it that normal pregnancy can be earliest detected by TVS (transvaginal USG) :

If the serum beta hcg value is more than 1500IU/L,and an intrauterine pregnancy is not visualized on TVS,it is likely to be an ectopic.This is the level at which an intrauterine gestational sac should be seen and in called the discriminatory zone.With TVS,it is considered to be 1500IU/L. Refer page no 161 of Text book ,sheila balakrishnan,2 nd edition.