<prompt> At what level of b-hCG is it that normal pregnancy can be earliest detected by TVS transvaginal USG?500 IUmL1000 IUmL1500 IUmL2000 IUmL  <response>: Ans. is b, i.e. 1000IUMLRef Dutta Obs. 7e, p 642Critical titre of hCG:b-hCG level mIUmlStructure visibleTVSTAS 1000-1200Gestational sacTVS 6000Gestational SacTAS 