Humasis

HUBI Cardiac DUO is one step in vitro diagnostic test based on immunochromatography. It must be used with HUBI QUAN pro and designed for quantitative determination of CK-MB, Cardiac Troponin I in human whole blood, plasma or serum.

The Troponin complex is located on the myosin filament of the actomyosin contractile apparatus of muscle. Troponin complex consist of Troponin T, which binds the Troponin complex to the tropomyosin strand, Troponin C, which binds calcium and regulates contraction, Troponin I, which inhibits myosin ATPase activity. There is one cardiac specific isoform of cTnl, with a molecular weight of 26.5kDa, cTnl becomes elevated 4~9 hours following an acute myocardial infarction (AMI) and remains elevated for about 6-10 days. Concentrations can increase 10~1000 times the upper limit of values found in normal healthy subjects. Smaller increases may be found in patients presenting with unstable angina, sepsis, pericarditis, injury due to trauma etc. TnT is a 39kDa protein. There are a number of cardiac isomers of TnT which have 40~45% dissimilarity with skeletal muscle TnT. 6~8% of cardiac TnT (cTnT) is found in the cytoplasm and the remainder is found complexed in tropomyosin, cTnT becomes elevated 4~9 hours following an acute myocardial infarction (AMI) and remains elevated for about 8 days. Levels may increase more than 100 times the upper limit of values found in normal healthy subjects. Smaller increases may be found in patients presenting with unstable angina.

Creatine Kinase MB(CK-MB)is an 82,000 Dalton cytosolic enzyme that is present in high concentrations in the myocardium. In the cells, the "cytosolic" CK enzymes consist of two subunits, which can be either B (brain type) or M (muscle type). There are, therefore, three different isoenzymes: CK-MM, CK-BB and CK-MB. Isoenzyme patterns differ in tissues. CK-BB occurs mainly in tissues, and its levels do rarely have any significance in bloodstream. Skeletal muscle expresses CK-MM (98%) and low levels of CK-MB (1%). The myocardium (heart muscle), in contrast, expresses CK-MM at 70% and CK-MB at 25-30%. CK-BB is expressed in all tissues at low levels and has little clinical relevance. This isoenzyme of creatine kinase is frequently used in the diagnosis of acute myocardial infarction. Typically, CK-MB increase above normal within the first four to eight hours following acute myocardial infarction, reaching maximum concentrations between 12 and 24 hours and returning to normal in approximately three days. CK-MB is not specifically localized in cardiac muscle. Blood concentrations of CK-MB can be elevated as a result of acute or chronic muscle damage, including strenuous exercise and trauma. Nonetheless, measurements of blood CK-MB concentrations are widely relied on for the management of patients having an AMI.