<prompt> Diagnosis of ectopic pregnancy can be made with predicted b-HCG levels of more than:1000mIUmL1500mIUmL2000 m IUmL2500 m IUmL  <response>: Ans. B. 1500 m IUmL. Ref TeLindes Operative Gynecology 10thpg. 804.TeLindes Operative Gynecology 10thpg. 804...Presently, TVS reliably detects intrauterine gestations as early as 1 week after missed menses ss-hCG 1,500 IU L; 5-6 weeks gestation. Barnhart and associates reported that with a ss-hCG cone of 1,500 IUL or higher, an empty uterus on TVS identified an ectopic pregnancy with 100 accuracy.Investigators reported that the detection of an adnexal mass in combination with an empty uterus had a sensitivity of 97, specificity of 99, positive predictive value of 98, and negative predictive value of 98, provided that serum ss- hCG concentrations exceeded 1,000 IUL. The coupling of hCG titers with transvaginal ultrasonographic findings has therefore greatly facilitated the early diagnosis of ectopic gestation.ss-hCG Assays The principal endocrine marker of pregnancy is hCG, which is synthesized by the syncitiotrophoblast. Human chorionic gonadotropin is a glycoprotein consisting of two subunits: alpha and ss.- The alpha subunit has significant homology with other glycoprotein hormones, such as follicle-stimulating hormone, luteinizing hormone, and thyroid-stimulating hormone.- The ss-subunit, on the other hand, is specific to hCG, and antibodies against the ss-subunit form the basis for current immunoassays. Current commercial automated ss-hCG immunoassays use enzyme fluorimetry, enzyme spectrometry, or chemiluminescence methods, as opposed to the traditional radioimmunoassay gold standard - RIA methods commonly used in the past. A immunoassay for ss-hCG can detect levels of hCG as low as 5 IUL of serum with less than a 0.2 incidence of false- negative results. ss-hCG can be detected in maternal serum as early as 7 to 8 days after ovulation, or approximately the day after blastocyst implantation Serum hCG concentrations increase in an exponential fashion in early pregnancy. ss-hCG concentrations tended to double every 2 days. 