Abstract: In order to explore the specificity of complement C5 in the postmortem diagnosis of myocardial infarction, changes of C5 staining in normal, infarcted and other non－ infarcted myocardia with direct or indirect myocardial injuries (myocarditis, mechanical asphyxia, electrocution, hemorrhagic shock, cardiac contusion and organophosphate poisoning) were studied with immunohistochemistry and image analysis. The results showed that positive C5 staining could be observed in groups of myocardial infarction and myocarditis, but not in groups of mechanical asphyxia, electrocution, hemorrhagic shock, cardiac contusion, and organophosphate poisoning. It is indicated that positive reaction of C5 could only be affected by myocarditis, which means that it was more specific for the diagnosis of myocardial infarction.

Key words: myocardial infarction, complement C5, immunohistochemistry, image analysis system, specificity