Diagnose skeletal or myocardial muscle injury. Serum myoglobin is generally detectable earlier than is CK or CK-MB increase in patients with acute myocardial infarction. Serum myoglobin was found also in 50% of patients with acute coronary insufficiency. It is thought to define a population of small infarcts of myocardium. It correlates with size of infarct. Diagnose rhabdomyolysis. Myoglobin appears with trauma, ischemia, malignant hyperthermia, exertion, dermatomyositis, polymyositis, and muscular dystrophy. 

Serum myoglobin is rapidly cleared by the kidneys. Urine myoglobin levels were not detected after myocardial infarct. Elevated myoglobin levels may be associated with cocaine abuse. Other conditions which cause elevation of serum myoglobin include open heart surgery, exercise, progressive muscular dystrophy, shock, and renal failure. It is increased in azotemic subjects and not effected by dialysis.