Myoglobin in serum
Reference values of myoglobin concentration in serum: men - 22-66 mcg / l, women - 21-49 mcg / l.
Myoglobin is a gem-containing chromoprotein;is a light chain of myosin with a molecular weight of 17.6 kDa. It is a protein transporting oxygen in skeletal muscles and myocardium. Myoglobin weakly binds to blood proteins;with damage to the myocardium and skeletal muscles easily and quickly enters the blood and then quickly excreted in the urine. The increase in blood concentration is transient, occurs only 2-3 hours after the onset of pain with MI and persists for 2-3 days. An increase in myoglobin concentration in the blood during the first 2 hours is revealed in 50%, by 3:00 in 92%, and by 5:00 in 100% of patients with MI.The concentration of myoglobin in MI can be increased 4-10 times or more. The degree of its increase depends on the magnitude of myocardial damage. Normalization of myoglobin concentration in MI occurs on 2-3 days. With the development of complications( heart failure), the myoglobin concentration remains elevated for more than 3 days. Repeated increases in myoglobin concentration in the blood on the background of already begun normalization may indicate an expansion of the MI zone or the formation of new necrotic foci. With myocardial ischemia occurring during angina attacks, without the development of focal necrotic changes, an increase in the concentration of myoglobin in the blood is also possible, but it is insignificant. In myocardial infarction, myoglobinemia is detected along with myoglobinemia( an increase in the content of myoglobin in the urine), which is not observed in angina attacks. Determination of myoglobin concentration in the blood is most important for early diagnosis of myocardial infarction.
The determination of myoglobin in the blood is important in patients with prolonged compression syndrome, with extensive muscle trauma, which is often complicated by ARF due to the massive deposition of myoglobin in the renal glomeruli.
Myoglobin concentration in the blood increases with severe electroshock, thermal burns, secondary toxic myoglobinuria( Huff's disease), skeletal muscle damage, arterial occlusion with muscle ischemia.