The correlation between AMH assays differs depending on actual AMH levels

STUDY QUESTION: What is the correlation of serum anti-Müllerian hormone (AMH) levels between two frequently used laboratory assays? SUMMARY ANSWER: A considerable difference was found in serum AMH levels measured with the two different assays, particularly for low AMH values. WHAT IS KNOWN ALREADY: AMH is regarded as being a robust, highly sensitive and specific biomarker for ovarian response and has become widely used as the basis for fertility treatment decisions. However, several available assays with different reference values, in addition to inter-laboratory variations and issues of sample stability, make interpretation of the AMH values and their clinical implications complicated. STUDY DESIGN, SIZE, DURATION: An observational study was performed including 269 serum samples from infertile women, originating from a RCT conducted in 2013-2016 (www.clinicaltrials.gov NCT02013973). PARTICIPANTS/MATERIALS, SETTING, METHOD: Serum AMH levels analysed with the Modified Beckman Coulter Gen II ELISA assay (Premix method) were compared to AMH levels analysed with the Beckman Coulter Gen II ELISA original assay (Gen II original). All samples were handled identically and analysed with the two assays in a parallel setting. MAIN RESULTS AND THE ROLE OF CHANCE: The slope of the regression line showed a mean of 18% higher values with the Premix method compared to the Gen II original assay, and more than 40% higher values for AMH levels in the lower range. LIMITATIONS, REASONS FOR CAUTION: The Gen II original assay is no longer in clinical use as it has been replaced by the Premix method, which, in turn, recently has been further developed into an automated method. WIDER IMPLICATIONS OF THE FINDINGS: The finding of differences in AMH levels between assays is clinically important and may imply an incorrect classification in the assessment of ovarian reserve. The robustness of serum AMH as a marker for ovarian reserve and as a tool for fertility counselling has to be investigated further. There is an urgent need for international standards on interpretation of AMH values for different assays. STUDY FUNDING/COMPETING INTERESTS: Financial support was received through Sahlgrenska University Hospital (ALFGBG-70940) and the Hjalmar Svensson Research Foundation. None of the authors declares any conflict of interest.