CLIA Reagents of Inflammation (NT-pro-BNP)

【Expected usage】

This product is used to quantitatively detect the content of N-terminal pro-brain natriuretic peptide (NT-proBNP) in human serum in vitro.

Heart failure is an important clinical syndrome that compromises left ventricular systolic or diastolic function, or both. Heart failure occurs when the heart cannot pump blood at the rate required by the body's metabolism. Common causes are coronary heart disease, hypertension, valvular heart disease and cardiomyopathy. Effective therapeutic interventions (eg, angiotensin-converting enzyme inhibitors, beta-blockers) can reduce morbidity and mortality, so early diagnosis is important. The New York Heart Association (NYHA) classifies heart failure into 4 grades (I-IV) based on the severity of clinical signs and symptoms.

BNP is a structurally identical family of natriuretic peptides, the natriuretic peptide system includes atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), C-type natriuretic peptide (CNP) and urodilatin. ANP and BNP are secreted products of the atrium and ventricle, most of the BNP is mainly secreted by the left ventricle, it is secreted from the precursor protein (proBNP), and proBNP is cleaved into active BNP and inactive NT-proBNP. The secretion of BNP can produce natriuretic, diuretic, vasodilatory and smooth muscle relaxation effects. Plasma ANP and BNP can be elevated in a variety of pathological conditions, especially in conditions of increased wall tension, increased circulating volume (eg, heart failure, renal failure, increased aldosterone, etc.) or decreased clearance of natriuretic peptides ( such as renal failure).

ANP is a small particle that is stored in the atrium and is a product of atrial stretch secretion, whereas BNP secretion is metabolically controlled and usually requires prolonged stimulation. Plasma BNP concentrations are elevated in patients with heart failure, and the degree of BNP elevation corresponds to the New York Heart Association (NYHA) classification. In addition, related studies have shown that many patients with myocardial injury have a certain increase in plasma BNP concentrations. Normal thresholds for plasma BNP concentrations have been established, although it is well known that plasma BNP concentrations are affected by age, sex, renal failure, and medication, especially some drugs such as diuretics and beta-blockers.

The N-terminal brain natriuretic peptide precursor is currently measured in clinical and laboratory methods including enzyme-linked immunosorbent assay, colloidal gold method, fluorescence immunoassay, and chemiluminescence method.

【Inspection Principle】

This kit adopts the principle of direct sandwich method, uses magnetic microparticles as the solid phase of immune reaction, and uses chemiluminescence enzyme-linked immunosorbent assay method to cooperate with chemiluminescence measuring instruments to detect the content of NT-proBNP in human serum.

The technical principle is: Fluorescein isothiocyanate (FITC)-labeled mouse monoclonal anti-NT-proBNP antibody paired with alkaline phosphatase (AP)-labeled mouse monoclonal anti-NT-proBNP antibody and samples, calibrators or The NT-proBNP in the control binds to form a "sandwich" complex. Subsequently, the magnetic particles linked with goat anti-fluorescein isothiocyanate (FITC) antibody were added, and the antigen-antibody immune complexes were bound to the magnetic particles through the specific binding of the anti-FITC antibody to FITC.

Under the action of an external magnetic field, the complex formed by the immune reaction is separated from other unbound substances, and after washing the complex, an enzymatic chemiluminescent substrate (adamantane derivative) is added. The substrate is catalytically cleaved under the action of the enzyme to form an unstable excited state intermediate.

When the excited state intermediate returns to the ground state, photons are emitted to form a luminescence reaction, and the luminescence intensity of the reaction can be detected by a chemiluminescence instrument. In the range of measurement wavelength (230-700nm), the luminescence intensity is proportional to the content of NT-proBNP in the sample, and the concentration of NT-proBNP in the sample can be calculated by fitting the modified four-parameter Logistic equation.