Provided herein is a library of monoclonal antibodies specific for native proteins and native protein complexes of the oxidative phosphorylation (OXPHOS) system (for example, Complex I, II, III, IV, or V, or any protein subunit of any of such complexes). Hybridomas expressing such antibodies and antibodies that competitively inhibit the binding of any such antibody (e.g., antibodies that bind the same or a sterically overlapping epitope) are also contemplated. Methods of using, and kits including, the disclosed antibodies are also provided. Antibodies, methods and kits described herein address a need in the art by providing immunological reagents and assays useful, at least, for detecting mitochondrial diseases associated with deficiencies or alterations in OXPHOS Complexes I, II, III, IV and / or V.