Early detection of pregnancy after IVF and embryo transfer with hyperglycosylated HCG versus Elecsys HCG+β assay

Research Question Is measurement of hyperglycosylated human chorionic gonadotropic (hhCG) superior to beta-HCG (HCG+β) for early pregnancy detection after in vitro fertilization (IVF)-embryo transfer (ET)? Design Blood samples for the purpose of this study were collected on Day 4 (+1), 7 (+1) and 11 (+2) after ET from women aged 18–45 years undergoing first/second fresh/frozen IVF-ET cycles. Biochemical pregnancy was assessed on-site by hCG determination on Day 11; clinical pregnancy was assessed by ultrasound on Day 21 (+4/-3). Serum hhCG (immunochemiluminometric assay; Quest Diagnostics) and HCG+β (Elecsys® HCG+β assay, Roche Diagnostics) levels were measured. Performance of hhCG and HCG+β for predicting pregnancy was evaluated and cut-offs selected. Results In total, 155 women were enrolled and received IVF-ET. Area under the curve (AUC) (95% confidence interval) at Day 4 was not significantly different for hhCG (0.88; 0.83–0.94) and HCG+β (0.90; 0.84–0.95), as was predictive performance on Day 7 and 11, with higher AUC estimates versus Day 4. Applying cut-offs derived according to Youden's index at Day 4 (hhCG, 100 pg/ml; HCG+β, 1.30 mIU/ml), both biomarkers demonstrated high negative predictive values for ruling out pregnancy (hhCG, 83.8%; HCG+β, 82.8%) and high positive predictive values for ruling in pregnancy (hhCG, 89.0%; HCG+β, 84.9%) at Day 21. Diagnostic performance improved from Day 4 through 11. Conclusions Predictive performance for early pregnancy post-IVF-ET of Day 5 blastocysts was not significantly different for hhCG and HCG+β; hhCG superiority over HCG+β was not shown.