Disclosed are compositions and methods for detecting and quantifying human anti- Mtillerian hormone (AMH) in biological samples. In particular, the invention provides novel methods of measuring different forms of AMH in a biological sample, such as human plasma The anti-AMH antibody compositions disclosed herein enable reproducible measurement and quantitation of AMH, including dimeric forms of the AMH protein and fragments thereof. The antibody compositions disclosed herein find particular utility as diagnostic tools for single epitope sandwich-based AMH assays, which can be used to diagnose a variety of medical conditions.