As latex agglutination turbidimetry of serum myoglobin (Mb) levels is simple, rapid and high sensitive method, it can be applied for early diagnosis and reperfusion therapy (PTCA, PTCR) in patients with acute myocardial infarction (AMI). The measurement of serum Mb levels is useful for early diagnosis of AMI, and we conclude that the measurement of serum Mb levels is useful and suitable for rapid judging on success or failure of reperfusion therapy use of the disappearance rate of it.