Recent advances in analytic techniques have increased the diagnostic value of creatine kinase MB (CK-MB), enabling earlier and more sensitive results. The CK-MB mass immunoassays, that utilise the monoclonal anti-CK-MB in conjunction with anti-M or anti-B antibodies, are able to measure accurately small changes during the early hours after myocardial infarction (MI). CK-MB has two main limitations in diagnosing MI neither of which however undermines its established clinical value: CK-MB is not perfectly specific to cardiac injury, with increase occurring also during massive musculoskeletal injury; furthermore, the early release pattern of CK-MB limits its value for the late MI diagnosis. For the foreseeable future evidence is compelling for greater access to rapid testing capabilities in emergency situations, using protocols incorporating CK-MB mass evaluation together with other biochemical markers, i.e. myoglobin and troponins.