Enlightenment about the new Architect-i2000 estradiol (Abbott Laboratories) immunoassay during in vitro fertilization

EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third- versus second-generation estradiol and progesterone immunoassays

PURPOSE

To assess estradiol (E₂) and progesterone levels during ovarian stimulation determined by third-generation (Gen III) and second-generation (Gen II) Elecsys^® immunoassays.

METHODS

E₂ and progesterone concentrations were measured using Elecsys^® Gen III and Gen II immunoassays, and progesterone concentrations on the day of ovulation triggering were determined by LC-MS/MS. This was a retrospective, non-interventional study conducted at European tertiary referral infertility clinics in women aged 18-45 years, with a body mass index 18-35 kg/m², regular menses, and both ovaries.

RESULTS

Serum samples were obtained from 230 women classified by oocyte retrieval as poor (33.0%; 0-3 oocytes), normal (40.9%; 4-15 oocytes), or high (26.1%; > 15 oocytes) responders. E₂ and progesterone levels increased during ovarian stimulation, with greatest increases observed in high responders. Elecsys^® Gen III and Gen II assay results were highly correlated for E₂ (Pearson's r = 0.99) and progesterone (r = 0.89); Gen III results were lower than Gen II for both E₂ and progesterone. On the day of triggering, Gen III E₂ and progesterone levels showed a difference of - 15.0% and - 27.9%, respectively. Progesterone levels (on day of triggering) measured by LC-MS/MS correlated better with Gen III (0.98) than Gen II (0.90). Mean relative differences for Gen III and Gen II assays versus LC-MS/MS were 14.6% and 62.8%, respectively.

CONCLUSION

E₂ and progesterone levels determined with Elecsys^® Gen II and III assays were highly correlated; results were lower for Gen III versus Gen II. Differences observed for progesterone on the day of triggering may be clinically relevant.

Optimization of oestradiol assays to improve utility in an in vitro fertilization setting

Background The measurement of oestradiol is an integral component for the management of ovarian stimulation for in vitro fertilization. Automated immunoassays offer fast assay times and high throughput, with less sensitivity and specificity. The aim of this study is to optimize the oestradiol assay in patients undergoing ovarian stimulation for in vitro fertilization via comparison of oestradiol values obtained using two immunoassays compared with mass spectrometry. Methods Patients undergoing ovarian stimulation were prospectively recruited. Serum samples were analysed with ADVIA Centaur® CP Immunoassay, Abbott Architect i1000® immunoassay and AB Sciex 5500 liquid chromatography-tandem mass spectrometry (LC-MS/MS) systems. Per cent bias was determined for each system to report the average tendency of the values to be larger or smaller than the LC-MS/MS value. Linear regression of total follicular volume and oestradiol was computed. Results The ADVIA Centaur® CP assay had a positive bias of 20% compared with LC-MS/MS, while the Architect i1000® had a non-significant, negative bias of 0.3%. With regression fit, a clear, positive relationship was seen between follicular volume and oestradiol. The Architect i1000® assay had a greater correlation (R²= 0.46) compared with Centaur® CP (R²= 0.36), when oestradiol values were >1000 pg/mL (3670 pmol/L). Conclusions The Abbott Architect i1000® oestradiol assay exhibits greater agreement with LC-MS/MS and exhibited better correlation to follicular volume when oestradiol values are >1000 pg/mL (3670 pmol/L), prompting a change in the clinic's oestradiol platform. Attention to assay quality assurance via LC-MS/MS can improve the oestradiol accuracy and permit more informed clinical decisions for improved patient outcomes.