Demonstration of Cardiac Muscle Antibody (CMA) by utilizing the indirect fluorescence enables serologic assessment or possible detection of cardiac disease. The presence of a (histologically defined) circulating antibody to one or more of the cardiac muscle antigens can aid in patient diagnosis and prognosis of such diseases as: rheumatic fever, myocardial infarction and a variety of post cardiotomy states.

The presence of CMA has been reported in 25-43% of cases of active rheumatic fever; however, the level of antibody does decrease during remission of the active disease. Patients with many attacks of rheumatic fever are more likely to demonstrate CMA than those with relatively few attacks. Myocardial infarction patients have been shown to demonstrate CMA (28-31%). The level of this antibody in acute myocardial infarction cases and the rather rare occurrence of the antibody in coronary insufficient cases without infarction can be useful information in a differential diagnosis between the two diseases. Postcardiotomy patients have demonstrated CMA.