Effect of Delayed Processing on High-Sensitivity C-Reactive Protein

The concentration of C-reactive protein (CRP) in blood is considered a marker of inflammation; it is also predictive of cardiovascular disease and possibly cancer (1)(2). Although CRP is frequently measured in large studies, the effects of storage conditions and delays in processing on those measurements are largely unknown. In whole blood samples stored at ambient temperature, CRP has been reported to be stable for 6 h (3) and for 3 days(4), and in samples stored on ice it has been reported as stable for 36 h (5). However, in multicenter studies for which analyses are conducted at a single site, specimens are often shipped overnight. It is possible to ship specimens under refrigerated or frozen conditions, but doing so adds to the cost of the study. We therefore assessed the stability of high-sensitivity CRP (hsCRP) in unprocessed whole blood samples shipped overnight at ambient temperature. This study was part of a larger study of changes in immune and …