Assessment of a Serum Assay for Quantification of Abdominal Aortic Calcification

Intimal vascular calcification is an important marker of atherosclerosis, and its severity is an independent risk factor for cardiovascular events. Measurement of coronary or aortic calcification requires CT-based imaging and elaborate data analysis to ensure accuracy. A blood assay which could quantify the severity of vascular calcification would be less expensive, avoid exposure to radiation, and be more accessible than present imaging based methods. Osteoprotegerin (OPG) and osteopontin (OPN) are present in human serum and have been implicated in vascular calcification. In this prospective study we assessed the value of a number of serum assays for OPG and OPN in determining abdominal aortic calcification. Firstly, we investigated the assay characteristics and reproducibility of 5 ELISAs using a subset of patients. Based on the findings of these assessments, we selected 3 assays for full evaluation in the entire cohort.