Purpose: To investigate the stability and repeatability of electrochemiluminescence immunoassay (ECLIA) for beta-hCG detection in embryo spent culture media. To evaluate the correlation between the viability of preimplantation embryo and beta-hCG profile by the new assay.
Methods: In a retrospective study, a total of 357 spent culture media from day1 to day5 were individually collected and quantified by ECLIA. The blank controls and reliability test were performed with normal saline/pure culture media.
Results: 1) There was no detectable amount of beta-hCG in blank controls. A high degree of linearity (R(2) = 0.995) was found in this study; intra-assay and inter-assay coefficient of variation were 4.87 % and 6.25 %. 2) A significantly higher concentration of beta-hCG was found at day5 group than it at day3 group, both in total samples (1.47 ± 0.68mIU/ml vs 0.55 ± 0.32mIU/ml) and in homologous embryo samples (1.43 ± 0.91mIU/ml vs 0.52 ± 0.23mIU/ml). 3) There was a positive correlation between beta-hCG concentration and implantation rate (r = 0.559 at day3 and 0.535 at day5) or blastocyst morphological grading (r = 0.411).
Conclusions: ECLIA may be an optimal choice for detecting beta-hCG in spent culture media to assess embryo viability, indicating secreted beta-hCG as a useful biomarker for embryo selection in IVF-ET procedure.