Immunoradiometric assay of circulating C-reactive protein: age-related values in the adult general population

Background: Increased values of C-reactive protein (CRP), the classical acu te phase protein, within the range below 5 mg/L, previously considered to b e within the reference interval, are strongly associated with increased ris k of atherothrombotic events, and are clinically significant in osteoarthri tis and neonatal infection. Methods: A robust new polyclonal-monoclonal solid-phase IRMA for CRP was de veloped, with a range of 0.05-10.0 mg/L. Results: Plasma CRP values in general adult populations from Augsburg, Germ any (2291 males and 2203 females; ages, 25-74 years) and Glasgow, Scotland (604 males and 650 females; ages, 25-64 years) were very similar. The media n CRP approximately doubled with age, from similar to 1 mg/L in the younges t decade to similar to 2 mg/L in the oldest, and tended to be higher in fem ales. Conclusion: This extensive data set, the largest such study of CRP, provide s valuable reference information for future clinical and epidemiological in vestigations. (C) 2000 American Association for Clinical Chemistry.