Troponin

Troponin is a complex composed of three subunits, troponin C, troponin I, and troponin T. Troponin (cTn) is considered to be the most specific biochemical marker for ACS diagnosis. They appear early and can appear as early as 2h after symptom onset; have a wide diagnostic window cTnT (5-14 days), cTnI (4 ~10 days). In their diagnostic window, the increase in cTn is 5 to 10 times higher than that of CK-MB. Since cTn is low in blood in the absence of myocardial damage, it can also be used for the diagnosis of minormycardialdamage (MMD, micro-myocardial injury), which is difficult to achieve with previous enzymatic indicators. cTn also has the value of prognosis. For patients with coronary artery disease, even if the ECG or other tests (such as exercise test) are negative, as long as cTn is increased, it should be considered as a high risk. Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Normal value: no Above normal: negative: normal. Positive: Common in myocardial ischemic injury, such as myocardial infarction, acute angina, unstable angina, heart surgery and so on. Tips: Patients with severe skeletal muscle injuries will have false positives. Normal value Troponin consists of three subunits: troponin T (TnT), troponin I (TnI) and troponin C (TnC). TnC The molecular weight is 18000, which has a crystal structure and is the Ca2+ binding subunit of troponin. The TnC in skeletal muscle and myocardium is the same. TnI The molecular weight is 23000, which is the actin inhibitory subunit. It has three subtypes: fast skeletal muscle subtype, slow skeletal muscle subtype and myocardial subtype. These three TnI subtypes are derived from three different genes. The myocardial subtype (cTnI) is about 40% different from the two skeletal muscle subtypes. The release form of cTnI after AMI (the free form is combined with other troponin to form a complex, oxidized form or reduced form) Still not completely clear. TnT The molecular weight is 37,000, which may be an asymmetric protein structure, and is a tropomyosin-binding subunit. TnT also has three subtypes: fast skeletal muscle subtype, slow skeletal muscle subtype and myocardial subtype. They are in skeletal muscle or myocardium. The expression is regulated by different genes. The half-life of troponin in circulating blood is about several hours, excreted by the kidney. The half-life of free cTnI in circulating blood is about 67min. AQT90FLEX rapid immunoassay troponin T detection (y) and Roche Elecsys2010 troponin T fourth generation detection (x) relationship (regression analysis): y = 1.033x - 0.006; r = 0.999; n = 390 Normal troponin value: dry film method: TnI negative; Immunological method: TnT0 ~ 0.15μg / L. Clinical significance Abnormal result Raise After myocardial injury, TnI and TnT appear in the blood at the earliest time and last for a long time. Therefore, TnI and TnT are a more specific and sensitive indicator of myocardial injury, and TnI is more sensitive than TnT. Elevated troponin is most common in myocardial ischemic injury, such as myocardial infarction, acute angina, unstable angina, and cardiac surgery. TnT in acute myocardial infarction increased rapidly, significantly and continuously, reaching 30-40 times of normal value; elevated serum troponin T in patients with unstable angina suggests a small range of myocardial necrosis. People who need to be tested Patients with myocardial infarction, patients with acute angina pectoris, patients with unstable angina, and so on. Positive results may be diseases: myocarditis, pediatric viral myocarditis, viral myocarditis, organophosphorus pesticide poisoning, Lyme carditis, stable angina pectoris, variant angina pectoris, young myocardial infarction, unstable angina in the elderly, unstable Angina precautions At the time of inspection: Different manufacturers' kits have different requirements for specimens, and blood should be taken as required. Inappropriate population: Severe hemolysis will affect the results of the assay. Patients with severe skeletal muscle injuries produce false positives. Inspection process The measurement of troponin mainly adopts the immunological method of double antibody sandwich, and the detection methods include chemiluminescence and electrochemiluminescence. Not suitable for the crowd Severe hemolysis will affect the results of the assay. Patients with severe skeletal muscle injuries produce false positives. Adverse reactions and risks There are no obvious complications.