Cardiac myosin-binding protein C (cMyBP-C, MYBPC3, cMyC; UniProtKB—Q14896) is a 140 kDa sarcomeric protein that is loosely associated with both myosin and actin. It was identified in the coronary effluent from ischaemic myocardium about 10 years ago and after systematic screening of monoclonal antibodies a sensitive sandwich immunoassay was formulated. Using this assay, cMyC has been measured in a variety of patient groups and directly compared to cardiac troponin T (cTnT) and cardiac troponin I (cTnI) measured in the same blood samples using high-sensitivity assays.