Development and Validation of an Automated and Ultrasensitive Immunoturbidimetric Assay for C-Reactive Protein

[摘要] C-Reactive protein (CRP) is a marker of acute phase response to inflammation that increases rapidly within hours of disease onset. CRP measurements have been used for many years in the management of a variety of clinical situations, such as bacterial infections, ischemic necrosis of tissue, and active inflammatory conditions (1). Recent studies of CRP concentrations within the conventional reference interval have suggested new clinical applications. CRP is a prognostic risk factor for coronary heart disease in both patients with angina (stable or not) and in apparently healthy subjects (2), and distinguishes rapidly destructive vs slowly progressive osteoarthritis (3). In neonates, CRP >1–2 mg/L could be associated with serious disease, usually bacterial infection (4). In most of these studies, the authors have proposed a cutoff point for CRP of 2–3 mg/L. Recent reports show median values in healthy controls of 0.58–1.72 mg/L, and 95 percentile ranges of ∼0.1–6.0 mg/L (5)(6). Nevertheless, these results can be influenced by the sensitivity of the methodology used for CRP quantification.Among the many commercially available assays for CRP, the most common use fluid-phase or particle-enhanced turbidimetric or nephelometric procedures (7). Such assays are suitable for the measurement of proteins at concentrations >5–10 mg/L. New methods of measuring CRP have lower limits of detection one-tenth those of earlier methods (8)(9). Some use expensive monoclonal antibodies, and others use higher sample volumes and antibody concentrations in the reaction mixtures, which can increase nonspecific reactions (10).We describe a microparticle reagent that we use in an optimized turbidimetric procedure with immunopurified polyclonal antibodies against CRP. It allows lower antibody coverage on the microparticle reagent and provides highly sensitive and robust particle-enhanced turbidimetric immunoassay for serum CRP. In addition, we present a new procedure of sequential covalent coupling of IgG and bovine serum albumin …

[学科分类] 过敏症与临床免疫学