The journey from the old to the new AMH assay: how to avoid getting lost in the values.

Anti-Müllerian hormone (AMH) is set to dominate reproductive endocrinology because of its unique relationship with the ovarian reserve. To date half of the published articles have used the Diagnostic Systems Lab (DSL) assay and the other half the Immunotech (IOT) assay. Unfortunately, these assays utilize two different primary antibodies against AMH and different standards, and consequently the crude values reported can differ substantially, with the IOT assay giving values for AMH that are higher than those obtained with the DSL assay. With the recent consolidation of these two companies by Beckman Coulter, and their sole ownership of the patent to measure mammalian AMH, there is finally a single commercially available assay - the AMH Gen II assay, which will fully replace the DSL and IOT assays. The aim of this article is to briefly focus on the different assays for AMH evaluation in order to give readers hopefully helpful suggestions for a correct interpretation of the AMH measurement. A brief overview on the development and performance characteristics of the new assay, how it relates to previous values and previously developed nomograms and where the future lies for AMH is also provided.