Diagnosis of ectopic pregnancy can be made with predicted b-HCG levels of more than:

Ans. B. 1500 m IU/mL. (Ref TeLinde's Operative Gynecology 10th/pg. 804).TeLinde's Operative Gynecology 10th/pg. 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 IU/L 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 IU/L. 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 IU/L 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."