New automated AntiMüllerian hormone (AMH) assays are more reliable than the manual assay in patients with reduced antral follicle count (AFC)

Abstract

To improve quality of AMH measurements, fully automated AMH assays have been recently developed. Yet, analytical data available failed to give emphasis on the necessary relationship between AMH and the number of AMH-producing antral follicles as a quality reference. Moreover, the relative performance of new automated and manual AMH assays in subgroups of patients displaying low, intermediate, and high AFC remained undetermined. Therefore, we decided to investigate the reliability and concordance of AMH levels obtained by one manual and two automated AMH assays in different AFC populations. Prospective study. Serum AMH levels were measured in frozen-thawed serum aliquots from 211 women, aged 24 to 43 years, using one manual (AMH Gen II) and two fully automated (Access AMH and Elecsys AMH) assays. AFC was performed on cycle-days 1-5 (same day of bloodwork) under strictly standardized conditions and sorted into 3 groups (tercile values): low AFC (3-12 follicles; n=73), intermediate AFC (13-20 follicles; n=65), and high AFC (21-84 follicles; n=73). The strenght of relationships between AFC and AMH levels was assessed by the Spearman correlation test and Spearman correlation coefficients were compared using the Fisher r-to-z transformation. Concordance among AMH assays was assessed graphically using the Bland-Altman plots and by Passing-Bablok regression. Overall, circulating AMH levels were lower (P< 0.001) with Access AMH (-16%) and Elecsys AMH (-20%) than with AMH Gen II. The limited amount of AMH values situated outside the ± 2 standard deviation interval in Bland-Altman plots (4.7% between AMH Gen II and Access AMH; 4.3% between AMH Gen II and Elecsys AMH; and 2.8% between Access and Elecsys AMH) indicated adequate concordance among assays, a phenomenon that tended to be improved in the low AFC group. Further, AFC was strongly correlated with AMH levels obtained with the 3 assays (r=0.83, P<0.001; r=0.83, P<0.001; and r=0.83, P<0.001, respectively) thereby confirming their comparable reliability. It is noteworthy that, in the low AFC group, AMH levels obtained by Access AMH and Elecsys AMH showed a stronger correlation with AFC (r=0.63; P<0.03 and r=0.65; P<0.005, respectively) than the AMH Gen II assay (r=0.52). This improved performance was not observed in the intermediate and the high AFC groups. As compared to conventional AMH Gen II assay results: 1. Serum AMH concentrations were -16% and -20% lower with Access AMH and Elecsys AMH, respectively, but concordance among techniques was adequate; 2. It was remarkable that both automated AMH assays were significantly more strongly correlated with AFC than the manual assay in patients endowed with few antral follicles. This constitutes a considerable advantage of the new AMH assays because this subset of patients is the main target for accurate ovarian function assessments.