Blood tests, also called biomarkers. play an important role in the diagnosis of myocardial infarction and myocarditis, heart failure, and arteriosclerosis. White blood cell count, CPK, cholesterol level, blood sugar level, CRP, etc. Tha test as important biomarkers have been used for a long time. In particular, there are tests called troponin and BNP, which are typical ones that are frequently used these days.
In myocardial infarction, the heart muscle (myocardium) becomes necrotic. When cardiomyocytes break down, an enzyme called myocardial deviation enzyme flows into the blood. There are several types of enzymes, but recently, the high-sensitivity troponin test, which can measure the enzyme troponin with high sensitivity, is very widely used for the rapid diagnosis of myocardial infarction (Fig. 2). Depending on the size of myocardial infarction, it can be high for 2-3 to 5-6 days after onset. According to various reports, both sensitivity and specificity are about 90-95%, and myocardial infarction can be diagnosed with extremely high accuracy.
Abbreviation for brain natriuretic peptide, which is a hormone secreted mainly from the ventricle of the heart. Historically, it was discovered in 1988 by a Japanese research group in the brain of pigs, so it was said that Brain B was taken and it was called a brain natriuretic peptide. It is called BNP. BNP is secreted slightly even under normal conditions, but when the heart is under stress such as heart failure, the secretion is significantly increased and the blood concentration rises. Currently, BNP has become an indispensable part of daily cardiovascular practice as a blood marker for examining the state of heart disease, especially the state of heart failure.
In Japan as well, a report of 1,098 human dock examinees found that the sensitivity to detect early heart failure was 90% and the specificity was 96%, showing high diagnostic ability. Given that the specificity of the electrocardiogram alone is 74%, the ability to accurately diagnose the disease is considered to be very high. There are two types of blood BNP measurement: BNP and NT-proBNP (human brain natriuretic peptide precursor N-terminal fragment). The heart produces the precursor pro-BNP, which is then broken down into BNP and NT-proBNP and released into the blood. NT-proBNP has been reported to be more stable, but there is no significant difference in clinical significance between the two.